[Federal Register Volume 62, Number 51 (Monday, March 17, 1997)]
[Rules and Regulations]
[Pages 12546-12564]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6506]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[FRL-5700-9]
RIN 2060-AE37
Test Methods for the Polymers and Resins I Rule; Appendix A, Test
Methods 310 A, B, C, 312 A, B, C, 313 A, B
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This action promulgates test methods 310 a, b and c, 312 a, b
and c, and 313 a and b for the detection of residual amounts of
hazardous air pollutants (HAPs) in conjunction with the recently issued
National Emission Standards for Hazardous Air Pollutants (NESHAP) for
the Manufacture of Major Elastomers, (commonly referred to as Polymers
and Resins I). The methods were adapted from industrial methods
submitted by the facilities in the polymers and resins industry and
were published for public comment as part of the Polymers and Resins I
proposed rulemaking action. The methods will be
[[Page 12547]]
promulgated, in conjunction with the Polymers and Resins I rule, as EPA
methods 310 a, b and c, 312 a, b and c, and 313 a and b, and will be
codified at 40 CFR Part 63, Appendix A.
Methods 310 a, b, and c are applicable for determining the residual
amount of solvent (hexane being the most commonly used solvent) and
diene monomer in ethylene-propylene terpolymer (EPDM) as produced in
the solution polymerization process. Methods 312 a, b, and c are
applicable for determining the residual amount of styrene in styrene-
butadiene rubber (SBR) as produced in the emulsion polymerization
process. Methods 313 a and b are applicable for determining the
residual amount of toluene, dimer, and styrene in polybutadiene rubber
(PBR) and SBR crumb as produced in the solution polymerization process.
All of the methods analyses are through the use of gas chromatography.
EFFECTIVE DATE: These methods are effective March 17, 1997.
ADDRESS: The background information for the promulgated test methods
may be obtained from: Air Docket Section (LE-131), Attention: Docket
No. A-92-44, U.S. Environmental Protection Agency, 401 M Street SW.,
Washington, DC 20460.
The docket is located at the above address in room M-1500,
Waterside Mall (ground floor), and may be inspected from 8 a.m. to 4
p.m., Monday through Friday; telephone number (202) 382-7548. A
reasonable fee may be charged for copying docket materials.
FOR FURTHER INFORMATION CONTACT: For information concerning the
methods, contact Mr. Solomon Ricks at (919) 541-5242, Emission
Measurement Center, Emission Monitoring and Analysis Division (MD-19),
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina, 27711.
SUPPLEMENTARY INFORMATION: Response to Comments: Concurrent with the
proposal of subpart U, the EPA proposed three test residual HAP test
methods--one each for SBRE, PBR/SBRS, and EPR. In determining the
methods to be included in the proposal, the industry was given the
opportunity to submit test methods for evaluation and approval by the
EPA. The EPA selected the test methods submitted by the Exxon Chemical
Company (Method 310), the Goodyear Tire and Rubber Company (Method
312), and the American Synthetic Rubber Corporation (Method 313) as the
test methods to be used to determine residual HAP concentration.
After proposal of the test methods, several commenters stated that
no single analytical method would produce consistent results for all
polymers. It was suggested by the companies that each company should be
allowed to demonstrate compliance using a company-specific method that
is comparable to the EPA test method. The EPA agreed with the
commenters and concluded that it was appropriate to allow every
interested company to validate their own test method using a modified
version of 40 CFR part 63, Appendix A, Method 301.
A total of eight test methods were submitted by seven different
companies. Throughout the process, the affected industry has been
involved with all activity associated with the EPA's promulgation of
the residual organic HAP test methods. The EPA held meetings with
industry representatives to discuss their comments on the proposed
methods, and to discuss procedures for validating company test methods.
Representatives of each of those three companies which did not submit
test methods were in attendance at one or more of the meetings.
This notice with the promulgated regulatory language is also
available on the Technology Transfer Network (TTN) on the EPA's
electronic bulletin boards. The TTN provides information and technology
exchange in various areas of air pollution control. The service is
free, except for the cost of a telephone call. Dial (919) 541-5742 for
up to a 14,400 bps modem. If more information on TTN is needed, call
the HELP line at (919) 541-5384.
Other materials related to this rulemaking are available for review
in the docket.
Judicial Review: Under section 307(b)(1) of the Act, judicial
review of the final rule is available only by filing a petition for
review in the U. S. Court of Appeals for the District of Columbia
Circuit within 60 days of today's publication of this final rule. Under
section 307(b)(2) of the Act, the requirements that are the subject of
today's notice may not be challenged later in civil or criminal
proceedings brought by the EPA to enforce these requirements.
I. Introduction
The methods being promulgated are to be used in testing for
residual amounts of HAPs to determine compliance with the standards in
the promulgated Polymers and Resins I rule (September 5, 1996, 61 FR
46906). The methods were published for comment along with the Polymers
and Resins I proposal under the authority of section 112(d) of the
Clean Air Act as amended in 1990. Section 112(d) requires the
Administrator to regulate emissions of HAP listed in section 112(b) of
the Clean Air Act. The Polymers and Resins I proposal was published for
public comment on June 12, 1995 (60 FR 30801).
The methods being promulgated will apply to ethylene-propylene
elastomers production, polybutadiene rubber production, and styrene-
butadiene rubber and latex production, using stripping technology as
the method of compliance. As stated in the promulgated Polymers and
Resins I rule, if compliance is to be demonstrated by sampling, samples
of the stripped wet crumb or stripped latex must be taken after the
stripper and analyzed to determine the residual HAP content.
II. Summary of Test Methods
A. Methods 310 a, b, and c
The promulgated methods are adapted from test methods submitted to
the EPA by DSM Copolymer, Uniroyal Chemical, and Exxon. These companies
are involved in the manufacture of EPDM rubber. The basic principle of
DSM Copolymer's methods involve heating a sample in a sealed bottle
with an internal standard and analyzing the vapor by gas
chromatography. Uniroyal Chemical extracts residual hexane contained in
wet pieces of EPDM polymer with methyl isobutyl ketone (MIBK). The
extract is then analyzed by gas chromatography. Exxon's principle
involves dissolving an EPDM crumb rubber sample in toluene to which
heptane has been added as an internal standard. Acetone is then added
to the solution to precipitate the crumb, and the supernatant is then
analyzed for hexane and diene by a gas chromatograph with a flame
ionization detector (FID).
B. Methods 312 a, b, and c
The promulgated methods are adapted from a test methods submitted
to the EPA by Goodyear Tire and Rubber Company, Ameripol Synpol
Corporation, and DSM Copolymer. The basic principle of the Goodyear
method is to coagulate the SBR latex sample with an an ethyl alcohol
solution containing a specific amount of alpha-methyl styrene as the
internal standard, and analyzing the extract to determine styrene
concentration using a gas chromatograph with a FID. Ameripol Synpol
coagulates the latex sample in propanol which contains alpha-methyl
styrene as the internal standard. The extract is then analyzed by a gas
chromatograph to determine the residual styrene from the latex. DSM
Copolymer utilizes a packed column gas chromatograph with a FID to
determine
[[Page 12548]]
the concentration of residual styrene in the latex samples.
C. Methods 313 a and b
The promulgated methods are adapted from test methods submitted to
the EPA by the American Synthetic Rubber Corporation (ASRC) and the
Goodyear Tire and Rubber Company. The basic principle of the ASRC
method involves placing the wet crumb sample in a sealed vial and
running on a headspace sampler which heats the vial to a specified
temperature for a specific time and then injects a known volume of
vapor into a capillary gas chromatograph. The method determines
residual toluene and styrene in the stripper crumb derived from
solution polymerization processes that utilize toluene as the
polymerization solvent. The Goodyear method uses the principle of
dissolving the polymer sample in chloroform and coagulating the cement
with an isopropyl alcohol solution containing a specific amount of
alpha-methyl styrene as the internal standard. The extract of this
coagulation is then injected into a gas chromatograph and separated
into individual components.
III. Significant Comments and Changes to Test Methods
When published with the Polymers and Resins I proposal, the methods
were proposed as methods 310, 312, and 313. The industry submitted
their test methods for EPA review, and it was left to the EPA to decide
which method would be acceptable as the test methods to be used for
compliance purposes. However, after proposal, the companies who
submitted their methods for consideration, and whose methods were not
selected, raised the issue that no single analytical method would
produce consistent results for all polymers. After review and
consideration of this issue, the EPA concluded that it was appropriate
to allow every interested company to validate their own test method
using a modified version of 40 CFR part 63, Appendix A, Method 301. The
results of this effort was to have a total of eight methods submitted
as validated test methods by seven companies. Only three affected
companies decided not to submit methods. Therefore, the final methods
rule include methods 310a, b, and c for EPR, methods 312a, b, and c for
SBRE, and methods 313a and b for PBR/SBRS, as acceptable residual
organic HAP test methods.
IV. Administrative Requirements
A. Docket
The docket is an organized and complete file for all information
submitted or otherwise considered by EPA in the development of this
promulgated rulemaking. The principal purposes of the docket are: (1)
to allow interested parties to identify and locate documents so that
they can effectively participate in the rulemaking process, and (2) to
serve as the record in case of judicial review (except for interagency
review materials) [Clean Air Act Section 307(d)(7)(A)].
B. Office of Management and Budget Review
Under Executive Order 12866 (58 FR 51735 October 4, 1993), the EPA
is required to judge whether a regulation is ``significant'' and
therefore subject to Office of Management and Budget (OMB) review and
the requirements of this Executive Order to prepare a regulatory impact
analysis (RIA). The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may: (1) Have an annual
effect on the economy of $100 million or more or adversely affect in a
material way the economy, a sector of the economy, productivity,
competition, jobs, the environment, public health or safety, or State,
local, or tribal governments or communities; (2) create a serious
inconsistency or otherwise interfere with an action taken or planned by
another agency; (3) materially alter the budgetary impact of
entitlements, grants, user fees, or loan programs, or the rights and
obligation of recipients thereof; or (4) raise novel legal or policy
issues arising out of legal mandates, the President's priorities, or
the principles set forth in the Executive Order.
Pursuant to the terms of the Executive Order, this action has been
determined to be ``not significant.''
C. Regulatory Flexibility Act
The EPA has determined that it is not necessary to prepare a
regulatory flexibility analysis in connection with this final rule. The
EPA has also determined that this rule will not have a significant
adverse impact on a substantial number of small businesses. This
rulemaking does not impose emission measurement requirements beyond
those specified in the current regulations, nor does it change any
emission standard, rather it provides acceptable test methods that the
businesses regulated by Polymers and Resins I may use to comply with
that rule. As such, it will not present a significant economic impact
on a substantial number of small businesses.
D. Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA)
Under 5 U.S.C. 801(a)(1)(A) as added by the Small Business
Regulatory Enforcement Fairness Act of 1996, EPA submitted a report
containing this rule and other required information to the U.S. Senate,
the U.S. House of Representatives and the Comptroller General of the
General Accounting Office prior to publication of the rule in today's
Federal Register. This rule is not a ``major rule'' as defined by 5
U.S.C. 804(2).
E. Paperwork Reduction Act
The rule does not impose or change any information collection
requirements subject to Office of Management and Budget review under
the Paperwork Reduction Act of 1980, 44 U.S.C. 3501 et seq.
F. Unfunded Mandates
Under Section 202 of the Unfunded Mandates Reform Act of 1995
(''Unfunded Mandates Act''), signed into law on March 22, 1995, EPA
must prepare a budgetary impact statement to accompany any proposed or
final rule that includes a Federal mandate that may result in estimated
costs to State, local, or tribal governments in the aggregate; or to
the private sector, of $100 million or more. Under Section 205, EPA
must select the most cost-effective and least burdensome alternative
that achieves the objectives of the rule and is consistent with
statutory requirements. Section 203 requires EPA to establish a plan
for significantly or uniquely impacted by the rule.
EPA has determined that the action proposed today does not include
a Federal mandate that may result in estimated costs of $100 million or
more to either State, local, or tribal governments in the aggregate, or
to the private sector, nor does this action significantly or uniquely
impact small governments, because this action contains no requirements
that apply to such govenments or impose obligations upon them.
Therefore, the requirements of the Unfunded Mandates Act do not apply
to this action.
List of Subjects in 40 CFR Part 63
Environmental protection, Emulsion polymerization, Gas
chromatography, Residual Hydrocarbon, Styrene, Solution polymerization.
[[Page 12549]]
Dated: March 4, 1997.
Carol M. Browner,
Administrator.
For the reasons set out in the preamble, Appendix A of Part 63 of
Title 40 of the CFR is amended as follows:
PART 63--[AMENDED]
1. The authority citation for Part 63 continues to read as follows:
Authority: 42 U.S.C. 7401, et seq.
2. Appendix A of Part 63 is amended by adding methods 310, 312, and
313 to read as follows:
APPENDIX A--TEST METHODS
* * * * *
METHOD 310A--DETERMINATION OF RESIDUAL HEXANE THROUGH GAS
CHROMATOGRAPHY
1.0 Scope and Application
1.1 This method is used to analyze any crumb rubber or water samples
for residual hexane content.
1.2 The sample is heated in a sealed bottle with an internal standard
and the vapor is analyzed by gas chromatography.
2.0 Summary of Method
2.1 This method, utilizing a capillary column gas chromatograph with a
flame ionization detector, determines the concentration of residual
hexane in rubber crumb samples.
3.0 Definitions
3.1 The definitions are included in the text as needed.
4.0 Interferences
4.1 There are no known interferences.
5.0 Safety
5.1 It is the responsibility of the user of this procedure to
establish safety and health practices applicable to their specific
operation.
6.0 Equipment and Supplies
6.1 Gas Chromatograph with a flame ionization detector and data
handling station equipped with a capillary column 30 meters long.
6.2 Chromatograph conditions for Sigma 1:
6.2.1 Helium pressure: 50# inlet A, 14# aux
6.2.2 Carrier flow: 25 cc/min
6.2.3 Range switch: 100x
6.2.4 DB: 1 capillary column
6.3 Chromatograph conditions for Hewlett-Packard GC:
6.3.1 Initial temperature: 40 deg.C
6.3.2 Initial time: 8 min
6.3.3 Rate: 0
6.3.4 Range: 2
6.3.5 DB: 1705 capillary column
6.4 Septum bottles and stoppers
6.5 Gas Syringe--0.5 cc
7.0 Reagents and Standards
7.1 Chloroform, 99.9+%, A.S.C. HPLC grade
8.0 Sample Collection, Preservation, and Storage
8.1 A representative sample should be caught in a clean 8 oz.
container with a secure lid.
8.2 The container should be labeled with sample identification, date
and time.
9.0 Quality Control
9.1 The instrument is calibrated by injecting calibration solution
(Section 10.2 of this method) five times.
9.2 The retention time for components of interest and relative
response of monomer to the internal standard is determined.
9.3 Recovery efficiency must be determined once for each sample type
and whenever modifications are made to the method.
9.3.1 Determine the percent hexane in three separate dried rubber
crumb samples.
9.3.2 Weigh a portion of each crumb sample into separate sample
bottles and add a known amount of hexane (10 microliters) by microliter
syringe and 20 microliters of internal standard. Analyze each by the
described procedure and calculate the percent recovery of the known
added hexane.
9.3.3 Repeat the previous step using twice the hexane level (20
microliters), analyze and calculate the percent recovery of the known
added hexane.
9.3.4 Set up two additional sets of samples using 10 microliters
and 20 microliters of hexane as before, but add an amount of water
equal to the dry crumb used. Analyze and calculate percent recovery to
show the effect of free water on the results obtained.
9.3.5 A value of R between 0.70 and 1.30 is acceptable.
9.3.6 R shall be used to correct all reported results for each
compound by dividing the measured results of each compound by the R for
that compound for the same sample type.
10.0 Calibration and Instrument Settings
10.1 Calibrate the chromatograph using a standard made by injecting 10
l of fresh hexane and 20 l of chloroform into a
sealed septum bottle. This standard will be 0.6 wt.% total hexane based
on 1 gram of dry rubber.
10.2 Analyze the hexane used and calculate the percentage of each
hexane isomer (2-methylpentane, 3-methylpentane, n-hexane, and
methylcyclo-pentane). Enter these percentages into the method
calibration table.
10.3 Heat the standard bottle for 30 minutes in a 105 deg.C oven.
10.4 Inject about 0.25 cc of vapor into the gas chromatograph and
after the analysis is finished, calibrate according to the procedures
described by the instrument manufacturer.
11.0 Procedure
11.1 Using a cold mill set at a wide roller gap (125-150 mm), mill
about 250 grams of crumb two times to homogenize the sample.
11.2 Weigh about 2 grams of wet crumb into a septum bottle and cap
with a septum ring. Add 20 l of chloroform with a syringe and
place in a 105 deg.C oven for 45 minutes.
11.3 Run the moisture content on a separate portion of the sample and
calculate the grams of dry rubber put into the septum bottle.
11.4 Set up the data station on the required method and enter the dry
rubber weight in the sample weight field.
11.5 Inject a 0.25 cc vapor sample into the chromatograph and push the
start button.
11.6 At the end of the analysis, the data station will print a report
listing the concentration of each identified component.
11.7 To analyze water samples, pipet 5 ml of sample into the septum
bottle, cap and add 20 l of chloroform. Place in a 105 deg.C
oven for 30 minutes.
11.8 Enter 5 grams into the sample weight field.
11.9 Inject a 0.25 cc vapor sample into the chromatograph and push the
start button.
11.10 At the end of the analysis, the data station will print a report
listing the concentration of each identified component.
12.0 Data Analysis and Calculation
12.1 For samples that are prepared as in section 11 of this method,
ppm
[[Page 12550]]
n-hexane is read directly from the computer.
12.2 The formulas for calculation of the results are as follows:
ppmhexane=(Ahexane x Rhexane)/(Ais x Ris)
Where:
Ahexane=area of hexane
Rhexane=response of hexane
Ais=area of the internal standard
Ris=response of the internal standard
% hexane in crumb=(ppmhexane/sample amount)100
12.3 Correct the results by the value of R (as determined in sections
9.3.4, 9.3.5, and 9.3.6 of this method).
13.0 Method Performance
13.1 The test has a standard deviation of 0.14 wt% at 0.66 wt% hexane.
Spike recovery of 12 samples at two levels of hexane averaged 102.3%.
Note: Recovery must be determined for each type of sample. The values
given here are meant to be examples of method performance.
14.0 Pollution Prevention
14.1 Waste generation should be minimized where possible. Sample size
should be an amount necessary to adequately run the analysis.
15.0 Waste Management
15.1 All waste shall be handled in accordance with federal and state
environmental regulations.
16.0 References and Publications
16.1 DSM Copolymer Test Method T-3380.
METHOD 310B--DETERMINATION OF RESIDUAL HEXANE THROUGH GAS
CHROMATOGRAPHY
1.0 Scope and Application
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Method sensitivity (5.5g
Analyte CAS No. Matrix sample size)
----------------------------------------------------------------------------------------------------------------
Hexane................................... 110-54-3 Rubber crumb............. .01 wt%.
Ethylidene norbornene (ENB).............. 16219-75-3 Rubber crumb............. .001 wt%.
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1.1 Data Quality Objectives:
In the production of ethylene-propylene terpolymer crumb rubber,
the polymer is recovered from solution by flashing off the solvent with
steam and hot water. The resulting water-crumb slurry is then pumped to
the finishing units. Certain amounts of solvent (hexane being the most
commonly used solvent) and diene monomer remain in the crumb. The
analyst uses the following procedure to determine those amounts.
2.0 Summary of Method
2.1 The crumb rubber sample is dissolved in toluene to which heptane
has been added as an internal standard. Acetone is then added to this
solution to precipitate the crumb, and the supernatant is analyzed for
hexane and diene by a gas chromatograph equipped with a flame
ionization detector (FID).
3.0 Definitions
3.1 Included in text as needed.
4.0 Interferences
4.1 None known.
4.2 Benzene, introduced as a contaminant in the toluene solvent,
elutes between methyl cyclopentane and cyclohexane. However, the
benzene peak is completely resolved.
4.3 2,2-dimethyl pentane, a minor component of the hexane used in our
process, elutes just prior to methyl cyclopentane. It is included as
``hexane'' in the analysis whether it is integrated separately or
included in the methyl cyclopentane peak.
5.0 Safety
5.1 This procedure does not purport to address all of the safety
concerns associated with its use. It is the responsibility of the user
of this procedure to establish appropriate safety and health practices
and determine the applicability of regulatory limitations prior to use.
5.2 Chemicals used in this analysis are flammable and hazardous (see
specific toxicity information below). Avoid contact with sources of
ignition during sample prep. All handling should be done beneath a
hood. Playtex or nitrile gloves recommended.
5.3 Hexane is toxic by ingestion and inhalation. Vapor inhalation
causes irritation of nasal and respiratory passages, headache,
dizziness, nausea, central nervous system depression. Chronic
overexposure can cause severe nerve damage. May cause irritation on
contact with skin or eyes. May cause damage to kidneys.
5.3 ENB may be harmful by inhalation, ingestion, or skin absorption.
Vapor or mist is irritating to the eyes, mucous membranes, and upper
respiratory tract. Causes skin irritation.
5.4 Toluene is harmful or fatal if swallowed. Vapor harmful if
inhaled. Symptoms: headache, dizziness, hallucinations, distorted
perceptions, changes in motor activity, nausea, diarrhea, respiratory
irritation, central nervous system depression, unconsciousness, liver,
kidney and lung damage. Contact can cause severe eye irritation. May
cause skin irritation. Causes irritation of eyes, nose, and throat.
5.5 Acetone, at high concentrations or prolonged overexposure, may
cause headache, dizziness, irritation of eyes and respiratory tract,
loss of strength, and narcosis. Eye contact causes severe irritation;
skin contact may cause mild irritation. Concentrations of 20,000 ppm
are immediately dangerous to life and health.
5.6 Heptane is harmful if inhaled or swallowed. May be harmful if
absorbed through the skin. Vapor or mist is irritating to the eyes,
mucous membranes, and upper respiratory tract. Prolonged or repeated
exposure to skin causes defatting and dermatitis.
5.7 The steam oven used to dry the polymer in this procedure is set at
110 deg. C. Wear leather gloves when removing bottles from the oven.
6.0 Equipment and Supplies
6.1 4000-ml volumetric flask
6.2 100-ml volumetric pipette
6.3 1000-ml volumetric flask
6.4 8-oz. French Square sample bottles with plastic-lined caps
6.5 Top-loading balance
6.6 Laboratory shaker
6.7 Laboratory oven set at 110 deg. C (steam oven)
6.8 Gas chromatograph, Hewlett-Packard 5890A, or equivalent,
interfaced with HP 7673A (or equivalent) autosampler (equipped with
nanoliter adapter and robotic arm), and HP 3396 series II or 3392A (or
equivalent) integrator/controller.
6.9 GC column, capillary type, 50m x 0.53mm, methyl silicone, 5
micron
[[Page 12551]]
film thickness, Quadrex, or equivalent.
6.10 Computerized data acquisition system, such as CIS/CALS
6.11 Crimp-top sample vials and HP p/n 5181-1211 crimp caps.
6.12 Glass syringes, 5-ml, with ``Luer-lock'' fitting
6.13 Filters, PTFE, .45m pore size, Gelman Acrodisc or
equivalent, to fit on Luer-lock syringes (in 6.12, above).
7.0 Reagents and Standards
7.1 Reagent toluene, EM Science Omnisolv
Purity Check: Prior to using any bottle of reagent toluene, analyze
it according to section 11.2 of this method. Use the bottle only if
hexane, heptane, and ENB peak areas are less than 15 each (note that an
area of 15 is equivalent to less than 0.01 wt% in a 10g sample).
7.2 Reagent acetone, EM Science Omnisolv HR-GC
Purity Check: Prior to using any bottle of reagent acetone, analyze
it according to section 11.2 of this method. Use the bottle only if
hexane, heptane, and ENB peak areas are less than 15 each.
7.3 Reagent heptane, Aldrich Chemical Gold Label, Cat #15,487-3
Purity Check: Prior to using any bottle of reagent heptane, analyze
it according to section 11.2 of this method. Use the bottle only if
hexane and ENB peak areas are less than 5 each.
7.4 Internal standard solution--used as a concentrate for preparation
of the more dilute Polymer Dissolving Solution. It contains 12.00g
heptane/100ml of solution which is 120.0g per liter.
Preparation of internal standard solution (polymer dissolving stock
solution):
------------------------------------------------------------------------
Action Notes
------------------------------------------------------------------------
7.4.1 Tare a clean, dry 1-liter If the 1-liter volumetric flask
volumetric flask on the balance. is too tall to fit in the
Record the weight to three places. balance case, you can shield
the flask from drafts by
inverting a paint bucket with
a hole cut in the bottom over
the balance cover. Allow the
neck of the flask to project
through the hole in the
bucket.
7.4.2 Weigh 120.00 g of n-heptane into Use 99+% n-heptane from Aldrich
the flask. Record the total weight of or Janssen Chimica.
the flask and heptane as well as the
weight of heptane added.
7.4.3 Fill the flask close to the mark Use EM Science Omnisolve
with toluene, about 1 to 2'' below the toluene, Grade TX0737-1, or
mark. equivalent.
7.4.4 Shake the flask vigorously to Allow any bubbles to clear
mix the contents. before proceeding to the next
step.
7.4.5 Top off the flask to the mark
with toluene. Shake vigorously, as in
section 5.4.4 of this method, to mix
well.
7.4.6 Weigh the flask containing the
solution on the three place balance
record the weight
7.4.7 Transfer the contents of the Discard any excess solution
flask to a 1 qt Boston round bottle.
7.4.8 Label the bottle with the Be sure to include the words
identity of the contents, the weights ``Hexane in Crumb Polymer
of heptane and toluene used, the date Dissolving Stock Solution'' on
of preparation and the preparer's name. the label.
7.4.9 Refrigerate the completed blend
for the use of the routine Technicians.
------------------------------------------------------------------------
7.5 Polymer Dissolving Solution (``PDS'')--Heptane (as internal
standard) in toluene. This solution contains 0.3g of heptane internal
standard per 100 ml of solution.
7.5.1 Fill a 4000ml volumetric flask about \3/4\ full with
toluene.
7.5.2 Add 100 ml of the internal standard solution (section 7.4 of
this method) to the flask using the 100ml pipette.
7.5.3 Fill the flask to the mark with toluene. Discard any excess.
7.5.4 Add a large magnetic stirring bar to the flask and mix by
stirring.
7.5.5 Transfer the polymer solvent solution to the one-gallon
labeled container with 50ml volumetric dispenser attached.
7.5.6 Purity Check: Analyze according to section 11.2. NOTE: You
must ``precipitate'' the sample with an equal part of acetone (thus
duplicating actual test conditions-- see section 11.1 of this method,
sample prep) before analyzing. Analyze the reagent 3 times to quantify
the C6 and ENB interferences. Inspect the results to ensure good
agreement among the three runs (within 10%).
7.5.7 Tag the bottle with the following information:
POLYMER DISSOLVING SOLUTION FOR C6 IN CRUMB ANALYSIS
PREPARER'S NAME
DATE
CALS FILE ID'S OF THE THREE ANALYSES FOR PURITY (from section
7.5.6 of this method)
7.6 Quality Control Solution: the quality control solution is prepared
by adding specific amounts of mixed hexanes (barge hexane), n-nonane
and ENB to some polymer dissolving solution. Nonane elutes in the same
approximate time region as ENB and is used to quantify in that region
because it has a longer shelf life. ENB, having a high tendency to
polymerize, is used in the QC solution only to ensure that both ENB
isomers elute at the proper time.
First, a concentrated stock solution is prepared; the final QC
solution can then be prepared by diluting the stock solution.
7.6.1 In preparation of stock solution, fill a 1-liter volumetric
flask partially with polymer dissolving solution (PDS)--see section 7.5
of this method. Add 20.0 ml barge hexane, 5.0 ml n-nonane, and 3 ml
ENB. Finish filling the volumetric to the mark with PDS.
7.6.2 In preparation of quality control solution, dilute the
quality control stock solution (above) precisely 1:10 with PDS, i.e. 10
ml of stock solution made up to 100 ml (volumetric flask) with PDS.
Pour the solution into a 4 oz. Boston round bottle and store in the
refrigerator.
8.0 Sample Collection, Preservation and Storage
8.1 Line up facility to catch crumb samples. The facility is a special
facility where the sample is drawn.
8.1.1 Ensure that the cock valve beneath facility is closed.
[[Page 12552]]
8.1.2 Line up the system from the slurry line cock valve to the
cock valve at the nozzle on the stripper.
8.1.3 Allow the system to flush through facility for a period of
30 seconds.
8.2 Catch a slurry crumb sample.
8.2.1 Simultaneously close the cock valves upstream and downstream
of facility.
8.2.2 Close the cock valve beneath the slurry line in service.
8.2.3 Line up the cooling tower water through the sample bomb
water jacket to the sewer for a minimum of 30 minutes.
8.2.4 Place the sample catching basket beneath facility and open
the cock valve underneath the bomb to retrieve the rubber crumb.
8.2.5 If no rubber falls by gravity into the basket, line up
nitrogen to the bleeder upstream of the sample bomb and force the
rubber into the basket.
8.2.6 Close the cock valve underneath the sample bomb.
8.3 Fill a plastic ``Whirl-pak'' sample bag with slurry crumb and send
it to the lab immediately.
8.4 Once the sample reaches the lab, it should be prepped as soon as
possible to avoid hexane loss through evaporation. Samples which have
lain untouched for more than 30 minutes should be discarded.
9.0 Quality Control
Quality control is monitored via a computer program that tracks
analyses of a prepared QC sample (from section 7.6.2 of this method).
The QC sample result is entered daily into the program, which plots the
result as a data point on a statistical chart. If the data point does
not satisfy the ``in-control'' criteria (as defined by the lab quality
facilitator), an ``out-of-control'' flag appears, mandating corrective
action.
In addition, the area of the n-heptane peak is monitored so that
any errors in making up the polymer dissolving solution will be caught
and corrected. Refer to section 12.4 of this method.
9.1 Fill an autosampler vial with the quality control solution (from
section 7.6.2 of this method) and analyze on the GC as normal (per
section 11 of this method).
9.2 Add the concentrations of the 5 hexane isomers as they appear on
the CALS printout. Also include the 2,2-dimethyl-pentane peak just
ahead of the methyl cyclopentane (the fourth major isomer) peak in the
event that the peak integration split this peak out. Do not include the
benzene peak in the sum. Note the nonane concentration. Record both
results (total hexane and nonane) in the QC computer program. If out of
control, and GC appears to be functioning within normal parameters,
reanalyze a fresh control sample. If the fresh QC is not in control,
check stock solution for contaminants or make up a new QC sample with
the toluene currently in use. If instrument remains out-of-control,
more thorough GC troubleshooting may be needed.
Also, verify that the instrument has detected both isomers of ENB
(quantification not necessary--see section 7.0 of this method).
9.3 Recovery efficiency must be determined for each sample type and
whenever modifications are made to the method. Recovery shall be
between 70 and 130 percent. All test results must be corrected by the
recovery efficiency value (R).
9.3.1 Approximately 10 grams of wet EPDM crumb (equivalent to
about 5 grams of dry rubber) shall be added to six sample bottles
containing 100 ml of hexane in crumb polymer dissolving solution
(toluene containing 0.3 gram n-heptane/100 ml solution). The polymer
shall be dissolved by agitating the bottles on a shaker for 4 hours.
The polymer shall be precipitated using 100 ml acetone.
9.3.2 The supernatant liquid shall be decanted from the polymer.
Care shall be taken to remove as much of the liquid phase from the
sample as possible to minimize the effect of retained liquid phase upon
the next cycle of the analysis. The supernatant liquid shall be
analyzed by gas chromatography using an internal standard quantitation
method with heptane as the internal standard.
9.3.3 The precipitated polymer from the steps described above
shall be re-dissolved using toluene as the solvent. The toluene solvent
and acetone precipitant shall be determined to be free of interfering
compounds.
9.3.4 The rubber which was dissolved in the toluene shall be
precipitated with acetone as before, and the supernatant liquid
decanted from the precipitated polymer. The liquid shall be analyzed by
gas chromatography and the rubber phase dried in a steam-oven to
determine the final polymer weight.
9.3.5 The ratios of the areas of the hexane peaks and of the
heptane internal standard peak shall be calculated for each of the six
samples in the two analysis cycles outlined above. The area ratios of
the total hexane to heptane (R1) shall be determined for the two
analysis cycles of the sample set. The ratio of the values of R1 from
the second analysis cycle to the first cycle shall be determined to
give a second ratio (R2).
10.0 Calibration and Standardization
The procedure for preparing a Quality Control sample with the
internal standard in it is outlined in section 7.6 of this method.
10.1 The relative FID response factors for n-heptane, the internal
standard, versus the various hexane isomers and ENB are relatively
constant and should seldom need to be altered. However Baseline
construction is a most critical factor in the production of good data.
For this reason, close attention should be paid to peak integration.
Procedures for handling peak integration will depend upon the data
system used.
10.2 If recalibration of the analysis is needed, make up a calibration
blend of the internal standard and the analytes as detailed below and
analyze it using the analytical method used for the samples.
10.2.1 Weigh 5 g heptane into a tared scintillation vial to five
places.
10.2.2 Add 0.2 ml ENB to the vial and reweigh.
10.2.3 Add 0.5 ml hexane to the vial and reweigh.
10.2.4 Cap, and shake vigorously to mix.
10.2.5 Calculate the weights of ENB and of hexane added and divide
their weights by the weight of the n-heptane added. The result is the
known of given value for the calibration.
10.2.6 Add 0.4 ml of this mixture to a mixture of 100 ml toluene
and 100 ml of acetone. Cap and shake vigorously to mix.
10.2.7 Analyze the sample.
10.2.8 Divide the ENB area and the total areas of the hexane peaks
by the n-heptane area. This result is the ``found'' value for the
calibration.
10.2.9 Divide the appropriate ``known'' value from 10.2.5 by the
found value from 10.2.8. The result is the response factor for the
analyte in question. Previous work has shown that the standard
deviation of the calibration method is about 1% relative.
11.0 Procedure
11.1 SAMPLE PREPARATION
[[Page 12553]]
11.1.1 Tare an 8oz sample bottle--Tag attached, cap off; record
weight and sample ID on tag in pencil.
11.1.2 Place crumb sample in bottle: RLA-1: 20g; RLA-3: 10g--
(gives a dry wt of 10g); (gives a dry wt of
5.5g).
11.1.3 Dispense 100ml of PDS into each bottle. SAMPLE SHOULD BE
PLACED INTO SOLUTION ASAP TO AVOID HEXANE LOSS--Using ``Dispensette''
pipettor. Before dispensing, ``purge'' the dispensette (25% of its
volume) into a waste bottle to eliminate any voids.
11.1.4 Tightly cap bottles and load samples into shaker.
11.1.5 Insure that ``ON-OFF'' switch on the shaker itself is
``ON.''
11.1.6 Locate shaker timer. Insure that toggle switch atop timer
control box is in the middle (``off'') position. If display reads
``04:00'' (4 hours), move toggle switch to the left position. Shaker
should begin operating.
11.1.7 After shaker stops, add 100 ml acetone to each sample to
precipitate polymer. Shake minimum of 5 minutes on shaker--Vistalon
sample may not have fully dissolved; nevertheless, for purposes of
consistency, 4 hours is the agreed-upon dissolving time.
11.1.8 Using a 5-ml glass Luer-lock syringe and Acrodisc filter,
filter some of the supernatant liquid into an autosampler vial; crimp
the vial and load it into the GC autosampler for analysis (section 11.2
of this method)--The samples are filtered to prevent polymer buildup in
the GC. Clean the syringes in toluene.
11.1.9 Decant remaining supernatant into a hydrocarbon waste sink,
being careful not to discard any of the polymer. Place bottle of
precipitate into the steam oven and dry for six hours--Some grades of
Vistalon produce very small particles in the precipitate, thus making
complete decanting impossible without discarding some polymer. In this
case, decant as much as possible and put into the oven as is, allowing
the oven to drive off remaining supernatant (this practice is avoided
for environmental reasons). WARNING: OVEN IS HOT--110 deg.C (230 deg.
F).
11.1.10 Cool, weigh and record final weight of bottle.
11.2 GC ANALYSIS
11.2.1 Initiate the CALS computer channel.
11.2.2 Enter the correct instrument method into the GC's
integrator.
11.2.3 Load sample vial(s) into autosampler.
11.2.4 Start the integrator.
11.2.5 When analysis is complete, plot CALS run to check baseline
skim.
12.0 Data Analysis and Calculations
12.1 Add the concentrations of the hexane peaks as they appear on the
CALS printout. Do not include the benzene peak in the sum.
12.2 Subtract any hexane interferences found in the PDS (see section
7.5.6 of this method); record the result.
12.3 Note the ENB concentration on the CALS printout. Subtract any ENB
interference found in the PDS and record this result in a ``% ENB by
GC'' column in a logbook.
12.4 Record the area (from CALS printout) of the heptane internal
standard peak in a ``C7 area'' column in the logbook. This helps track
instrument performance over the long term.
12.5 After obtaining the final dry weight of polymer used (section
11.1.10 of this method), record that result in a ``dry wt.'' column of
the logbook.
12.6 Divide the %C6 by the dry weight to obtain the total PHR hexane
in crumb. Similarly, divide the %ENB by the dry weight to obtain the
total PHR ENB in crumb. Note that PHR is an abbreviation for ``parts
per hundred''. Record both the hexane and ENB results in the logbook.
12.7 Correct all results by the recovery efficiency value (R).
13.0 Method Performance
13.1 The method has been shown to provide 100% recovery of the hexane
analyte. The method was found to give a 6% relative standard deviation
when the same six portions of the same sample were carried through the
procedure. Note: These values are examples; each sample type must be
tested for sample recovery.
14.0 Pollution Prevention
14.1 Dispose of all hydrocarbon liquids in the appropriate disposal
sink system; never pour hydrocarbons down a water sink.
14.2 As discussed in section 11.1.9 of this method, the analyst can
minimize venting hydrocarbon vapor to the atmosphere by decanting as
much hydrocarbon liquid as possible before oven drying.
15.0 Waste Mamagement
15.1 The Technician conducting the analysis should follow the proper
waste management practices for their laboratory location.
16.0 References
16.1 Baton Rouge Chemical Plant Analytical Procedure no. BRCP 1302
16.2 Material Safety Data Sheets (from chemical vendors) for hexane,
ENB, toluene, acetone, and heptane
METHOD 310C--DETERMINATION OF RESIDUAL N-HEXANE IN EPDM RUBBER THROUGH
GAS CHROMATOGRAPHY
1.0 Scope and Application
1.1 This method describes a procedure for the determination of
residual hexane in EPDM wet crumb rubber in the 0.01--2% range by
solvent extraction of the hexane followed by gas chromatographic
analysis where the hexane is detected by flame ionization and
quantified via an internal standard.
1.2 This method may involve hazardous materials operations and
equipment. This method does not purport to address all the safety
problems associated with it use, if any. It is the responsibility of
the user to consult and establish appropriate safety and health
practices and determine the applicability of regulatory limitations
prior to use.
2.0 Summary
2.1 Residual hexane contained in wet pieces of EPDM polymer is
extracted with MIBK. A known amount of an internal standard (IS) is
added to the extract which is subsequently analyzed via gas
chromatography where the hexane and IS are separated and detected
utilizing a megabore column and flame ionization detection (FID). From
the response to the hexane and the IS, the amount of hexane in the EPDM
polymer is calculated.
3.0 Definitions
3.1 Hexane--refers to n-hexane
3.2 Heptane--refers to n-heptane
3.3 MIBK--methyl isobutyl ketone (4 methyl 2--Pentanone)
4.0 Interferences
4.1 Material eluting at or near the hexane and/or the IS will cause
erroneous results. Prior to extraction, solvent blanks must be analyzed
to confirm the absence of interfering peaks.
5.0 Safety
5.1 Review Material Safety Data Sheets of the chemicals used in this
method.
[[Page 12554]]
6.0 Equipment and Supplies
6.1 4 oz round glass jar with a wide mouth screw cap lid.
6.2 Vacuum oven.
6.3 50 ml pipettes.
6.4 A gas chromatograph with an auto sampler and a 50 meter, 0.53 ID,
methyl silicone column with 5 micron phase thickness.
6.5 Shaker, large enough to hold 10, 4 oz. jars.
6.6 1000 and 4000 ml volumetric flasks.
6.7 Electronic integrator or equivalent data system.
6.8 GC autosampler vials.
6.9 50 uL syringe.
7.0 Reagents and Standards
7.1 Reagent grade Methyl-Iso-Butyl-Ketone (MIBK)
7.2 n-heptane, 99% + purity
7.3 n-hexane, 99% + purity
8.0 Sample Collection
8.1 Trap a sample of the EPDM crumb slurry in the sampling apparatus.
Allow the crumb slurry to circulate through the sampling apparatus for
5 minutes; then close off the values at the bottom and top of the
sampling apparatus, trapping the crumb slurry. Run cooling water
through the water jacket for a minimum of 30 minutes. Expel the cooled
crumb slurry into a sample catching basket. If the crumb does not fall
by gravity, force it out with demineralized water or nitrogen. Send the
crumb slurry to the lab for analysis.
9.0 Quality Control
9.1 The Royalene crumb sample is extracted three times with MIBK
containing an internal standard. The hexane from each extraction is
added together to obtain a total hexane content. The percent hexane in
the first extraction is then calculated and used as the recovery factor
for the analysis.
9.2 Follow this test method through section 11.4 of the method. After
removing the sample of the first extraction to be run on the gas
chromatograph, drain off the remainder of the extraction solvent,
retaining the crumb sample in the sample jar. Rinse the crumb with
demineralized water to remove any MIBK left on the surface of the
crumb. Repeat the extraction procedure with fresh MIBK with internal
standard two more times.
9.3 After the third extraction, proceed to section 11.5 of this method
and obtain the percent hexane in each extraction. Use the sample weight
obtained in section 12.1 of this method to calculate the percent hexane
in each of the extracts.
9.4 Add the percent hexane obtained from the three extractions for a
total percent hexane in the sample.
9.5 Use the following equations to determine the recovery factor (R):
% Recovery of the first extraction=(% hexane in the first extract/total
% hexane) x 100
Recovery Factor (R)=(% Hexane Recovered in the first extract)/100
10.0 Calibration
10.1 Preparation of Internal Standard (IS) solution:
Accuracy weigh 30 grams of n-heptane into a 1000 ml volumetric
flask. Dilute to the mark with reagent grade MIBK. Label this Solution
``A''. Pipette 100 mls. of Solution A into a 4 liter volumetric flask.
Fill the flask to the mark with reagent MIBK. Label this Solution
``B''. Solution ``B'' will have a concentration of 0.75 mg/ml of
heptane.
10.2 Preparation of Hexane Standard Solution (HS):
Using a 50 uL syringe, weigh by difference, 20 mg of n-hexane into a 50
ml volumetric flask containing approximately 40 ml of Solution B. Fill
the flask to the mark with Solution B and mix well.
10.3 Conditions for GC analysis of standards and samples:
Temperature:
Initial=40 deg.C
Final=150 deg.C
Injector=160 deg.C
Detector=280 deg.C
Program Rate=5.0 deg.C/min
Initial Time=5 minutes Final Time=6 minutes
Flow Rate=5.0 ml/min
Sensitivity=detector response must be adjusted to keep the hexane and
IS on scale.
10.4 Fill an autosampler vial with the HS, analyze it three times and
calculate a Hexane Relative Response Factor (RF) as follows:
RF=(AIS x CHS x PHS)/(AHS x CIS x
PIS) (1)
Where:
A IS=Area of IS peak (Heptane)
AHS=Area of peak (Hexane Standard)
CHS=Mg of Hexane/50 ml HS
CIS=Mg of Heptane/50 ml IS Solution B
PIS=Purity of the IS n-heptane
PHS=Purity of the HS n-hexane
11.0 Procedure
11.1 Weight 10 grams of wet crumb into a tared (W1), wide mouth 4 oz.
jar.
11.2 Pipette 50 ml of Solution B into the jar with the wet crumb
rubber.
11.3 Screw the cap on tightly and place it on a shaker for 4 hours.
11.4 Remove the sample from the shaker and fill an autosampler vial
with the MIBK extract.
11.5 Analyze the sample two times.
11.6 Analyze the HS twice, followed by the samples. Inject the HS
twice at the end of each 10 samples or at the end of the run.
12.0 Calculations
12.1 Drain off the remainder of the MIBK extract from the polymer in
the 4 oz. jar. Retain all the polymer in the jar. Place the uncovered
jar and polymer in a heated vacuum oven until the polymer is dry.
Reweigh the jar and polymer (W2) and calculate the dried sample weight
of the polymer as follows:
Dried SW=W2--W1 (2)
12.2 Should the polymer be oil extended, pipette 10 ml of the MIBK
extract into a tared evaporating dish (W1) and evaporate to dryness on
a steam plate.
Reweigh the evaporating dish containing the extracted oil (W2).
Calculate the oil content of the polymer as follows:
Gram of oil extracted =5 (W2--W1) (3)
% Hexane in polymer=(As X RF X CIS X PIS)/(AIS X
SW) (4)
Where:
As=Area of sample hexane sample peak.
AIS=Area of IS peak in sample.
CIS=Concentration of IS in 50 ml.
PIS=Purity of IS.
SW=Weight of dried rubber after extraction. (For oil extended polymer,
the amount of oil extracted is added to the dry rubber weight).
% Corrected Hexane=(% Hexane in Polymer)/R (5)
R=Recovery factor determined in section 9 of this method.
13.0 Method Performance
13.1 Performance must be determined for each sample type by following
the procedures in section 9 of this method.
14.0 Waste Generation
14.1 Waste generation should be minimized where possible.
15.0 Waste Management
15.1 All waste shall be handled in accordance with Federal and State
environmental regulations.
16.0 References
(Reserved)
[[Page 12555]]
METHOD 312A--DETERMINATION OF STYRENE IN LATEX STYRENE-BUTADIENE
RUBBER, THROUGH GAS CHROMATOGRAPHY
1. Scope and Application
1.1 This method describes a procedure for determining parts per
million (ppm) styrene monomer (CAS No. 100-42-5) in aqueous samples,
including latex samples and styrene stripper water.
1.2 The sample is separated in a gas chromatograph equipped with a
packed column and a flame ionization detector.
2.0 Summary of Method
2.1 This method utilizes a packed column gas chromatograph with a
flame ionization detector to determine the concentration of residual
styrene in styrene butadiene rubber (SBR) latex samples.
3.0 Definitions
3.1 The definitions are included in the text as needed.
4.0 Interferences
4.1 In order to reduce matrix effects and emulsify the styrene,
similar styrene free latex is added to the internal standard. There are
no known interferences.
4.2 The operating parameters are selected to obtain resolution
necessary to determine styrene monomer concentrations in latex.
5.0 Safety
5.1 It is the responsibility of the user of this procedure to
establish appropriate safety and health practices.
6.0 Equipment and Supplies
6.1 Adjustable bottle-top dispenser, set to deliver 3 ml. (for
internal standard), Brinkmann Dispensette, or equivalent.
6.2 Pipettor, set to 10 ml., Oxford Macro-set, or equivalent.
6.3 Volumetric flask, 100-ml, with stopper.
6.4 Hewlett Packard Model 5710A dual channel gas chromatograph
equipped with flame ionization detector.
6.4.1 11 ft. x \1/8\ in. stainless steel column packed with 10% TCEP
on 100/120 mesh Chromosorb P, or equivalent.
6.4.2 Perkin Elmer Model 023 strip chart recorder, or equivalent.
6.5 Helium carrier gas, zero grade.
6.6 Liquid syringe, 25-l.
6.7 Digital MicroVAX 3100 computer with VG Multichrom software, or
equivalent data handling system.
6.6 Wire Screens, circular, 70-mm, 80-mesh diamond weave.
6.7 DEHA--(N,N-Diethyl hydroxylamine), 97+% purity, CAS No. 3710-84-7
6.8 p-Dioxane, CAS No. 123-91-1
7.0 Reagents and Standards
7.1 Internal standard preparation.
7.1.1 Pipette 5 ml p-dioxane into a 1000-ml volumetric flask and fill
to the mark with distilled water and mix thoroughly.
7.2 Calibration solution preparation.
7.2.1 Pipette 10 ml styrene-free latex (eg: NBR latex) into a 100-ml
volumetric flask.
7.2.2 Add 3 ml internal standard (section 7.1.1 of this method).
7.2.3 Weigh exactly 10l fresh styrene and record the weight.
7.2.4 Inject the styrene into the flask and mix well.
7.2.5 Add 2 drops of DEHA, fill to the mark with water and mix well
again.
7.2.6 Calculate concentration of the calibration solution as follows:
mg/l styrene=(mg styrene added)/0.1 L
8.0 Sample Collection, Preservation, and Storage
8.1 A representative SBR emulsion sample should be caught in a clean,
dry 6-oz. teflon lined glass container. Close it properly to assure no
sample leakage.
8.2 The container should be labeled with sample identification, date
and time.
9.0 Quality Control
9.1 The instrument is calibrated by injecting calibration solution
(Section 7.2 of this method) five times.
9.2 The retention time for components of interest and relative
response of monomer to the internal standard is determined.
9.3 Recovery efficiency must be determined once for each sample type
and whenever modifications are made to the method.
9.3.1 A set of six latex samples shall be collected. Two samples shall
be prepared for analysis from each sample. Each sample shall be
analyzed in duplicate.
9.3.2 The second set of six latex samples shall be analyzed in
duplicate before spiking each sample with approximately 1000 ppm
styrene. The spiked samples shall be analyzed in duplicate.
9.3.3 For each hydrocarbon, calculate the average recovery efficiency
(R) using the following equations:
where:
R=(Rn)/6
where:
Rn=(cns-cv)/Sn
n=sample number
cns=concentration of compound measured in spiked sample number n.
cnu= concentration of compound measured in unspiked sample number
n.
Sn=theoretical concentration of compound spiked into sample n.
9.3.4 A value of R between 0.70 and 1.30 is acceptable.
9.3.5 R is used to correct all reported results for each compound by
dividing the measured results of each compound by the R for that
compound for the same sample type.
10.0 Calibration and Instrument Settings
10.1 Injection port temperature, 250 deg.C.
10.2 Oven temperature, 110 deg.C, isothermal.
10.3 Carrier gas flow, 25 cc/min.
10.4 Detector temperature, 250 deg.C.
10.5 Range, 1X.
11.0 Procedure
11.1 Turn on recorder and adjust baseline to zero.
11.2 Prepare sample.
11.2.1 For latex samples, add 3 ml Internal Standard (section 7.1 of
this method) to a 100-ml volumetric flask. Pipet 10 ml sample into the
flask using the Oxford pipettor, dilute to the 100-ml mark with water,
and shake well.
11.2.2 For water samples, add 3 ml Internal Standard (section 7.1 of
this method) to a 100-ml volumetric flask and fill to the mark with
sample. Shake well.
11.3 Flush syringe with sample.
11.4 Carefully inject 2 l of sample into the gas
chromatograph column injection port and press the start button.
11.5 When the run is complete the computer will print a report of the
analysis.
12.0 Data Analysis and Calculation
12.1 For samples that are prepared as in section 11.2.1 of this
method:
ppm styrene = A x D
Where:
A = ``ppm'' readout from computer
D = dilution factor (10 for latex samples)
12.2 For samples that are prepared as in section 11.2.2 of this
method,
[[Page 12556]]
ppm styrene is read directly from the computer.
13.0 Method Performance
13.1 This test has a standard deviation (1) of 3.3 ppm at 100 ppm
styrene. The average Spike Recovery from six samples at 1000 ppm
Styrene was 96.7 percent. The test method was validated using 926 ppm
styrene standard. Six analysis of the same standard provided average
97.7 percent recovery. Note: These are example recoveries and do not
replace quality assurance procedures in this method.
14.0 Pollution Prevention
14.1 Waste generation should be minimized where possible. Sample size
should be an amount necessary to adequately run the analysis.
15.0 Waste Management
15.1 All waste shall be handled in accordance with Federal and State
environmental regulations.
16.0 References and Publications
16.1 40 CFR 63 Appendix A--Method 301 Test Methods Field Validation of
Pollutant Measurement
16.2 DSM Copolymer Test Method T-3060, dated October 19, 1995,
entitled: Determination of Residual Styrene in Latex, Leonard, C.D.,
Vora, N.M.et al
METHOD 312B--DETERMINATION OF RESIDUAL STYRENE IN STYRENE-BUTADIENE
(SBR) RUBBER LATEX BY CAPILLARY GAS CHROMATOGRAPHY
1.0 Scope
1.1 This method is applicable to SBR latex solutions.
1.2 This method quantitatively determines residual styrene
concentrations in SBR latex solutions at levels from 80 to 1200 ppm.
2.0 Principle of Method
2.1 A weighed sample of a latex solution is coagulated with an ethyl
alcohol (EtOH) solution containing a specific amount of alpha-methyl
styrene (AMS) as the internal standard. The extract of this coagulation
is then injected into a gas chromatograph and separated into individual
components. Quantification is achieved by the method of internal
standardization.
3.0 Definitions
3.1 The definitions are included in the text as needed.
4.0 Interferences
(Reserved)
5.0 Safety
5.1 This method may involve hazardous materials, operations, and
equipment. This method does not purport to address all of the safety
problems associated with its use. It is the responsibility of the user
of this method to establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use.
6.0 Equipment and Supplies
6.1 Analytical balance, 160 g capacity, and 0.1 mg resolution
6.2 Bottles, 2-oz capacity, with poly-cap screw lids
6.3 Mechanical shaker
6.4 Syringe, 10-ul capacity
6.5 Gas chromatograph, Hewlett Packard model 5890A, or equivalent,
configured with FID with a megabore jet, splitless injector packed with
silanized glass wool.
6.5.1 Establish the following gas chromatographic conditions, and
allow the system to thoroughly equilibrate before use.
Injection technique = Splitless
Injector temperature = 225 deg C
Oven temperature = 70 deg C (isothermal)
Detector: temperature = 300 deg C
range = 5
attenuation = 0
Carrier gas: helium = 47 ml/min
Detector gases: hydrogen = 30 ml/min
air = 270 ml/min
make-up = 0 ml/min
Analysis time: = 3.2 min at the specified carrier gas flow rate and
column temperature.
6.6 Gas chromatographic column, DB-1, 30 M X 0.53 ID, or equivalent,
with a 1.5 micron film thickness.
6.7 Data collection system, Perkin-Elmer/Nelson Series Turbochrom 4
Series 900 Interface, or equivalent.
6.8 Pipet, automatic dispensing, 50-ml capacity, and 2-liter
reservoir.
6.9 Flasks, volumetric, class A, 100-ml and 1000-ml capacity.
6.10 Pipet, volumetric delivery, 10-ml capacity, class A.
7.0 Chemicals and Reagents
CHEMICALS:
7.1 Styrene, C8H8, 99+%, CAS 100-42-5
7.2 Alpha methyl styrene, C9H10, 99%, CAS 98-83-9
7.3 Ethyl alcohol, C2H5OH, denatured formula 2B, CAS 64-17-5
REAGENTS:
7.4 Internal Standard Stock Solution: 5.0 mg/ml AMS in ethyl alcohol.
7.4.1 Into a 100-ml volumetric flask, weigh 0.50 g of AMS to the
nearest 0.1 mg.
7.4.2 Dilute to the mark with ethyl alcohol. This solution will
contain 5.0 mg/ml AMS in ethyl alcohol and will be labeled the AMS
STOCK SOLUTION.
7.5 Internal Standard Working Solution: 2500 ug/50 ml of AMS in ethyl
alcohol.
7.5.1 Using a 10 ml volumetric pipet, quantitatively transfer 10.0
ml of the AMS STOCK SOLUTION into a 1000-ml volumetric flask.
7.5.2 Dilute to the mark with ethyl alcohol. This solution will
contain 2500 ug/50ml of AMS in ethyl alcohol and will be labeled the
AMS WORKING SOLUTION.
7.5.3 Transfer the AMS WORKING SOLUTION to the automatic
dispensing pipet reservoir.
7.6 Styrene Stock Solution: 5.0 mg/ml styrene in ethyl alcohol.
7.6.1 Into a 100-ml volumetric flask, weigh 0.50 g of styrene to
the nearest 0.1 mg.
7.6.2 Dilute to the mark with ethyl alcohol. This solution will
contain 5.0 mg/ml styrene in ethyl alcohol and will be labeled the
STYRENE STOCK SOLUTION.
7.7 Styrene Working Solution: 5000 ug/10 ml of styrene in ethyl
alcohol.
7.7.1 Using a 10-ml volumetric pipet, quantitatively transfer 10.0
ml of the STYRENE STOCK SOLUTION into a 100-ml volumetric flask.
7.7.2 Dilute to the mark with ethyl alcohol. This solution will
contain 5000 ug/10 ml of styrene in ethyl alcohol and will be labeled
the STYRENE WORKING SOLUTION.
8.0 Sample Collection, Preservation and Storage
8.1 Label a 2-oz sample poly-cap lid with the identity, date and time
of the sample to be obtained.
8.2 At the sample location, open sample valve for at least 15 seconds
to ensure that the sampling pipe has been properly flushed with fresh
sample.
8.3 Fill the sample jar to the top (no headspace) with sample, then
cap it tightly.
8.4 Deliver sample to the Laboratory for testing within one hour of
sampling.
8.5 Laboratory testing will be done within two hours of the sampling
time.
8.6 No special storage conditions are required unless the storage time
[[Page 12557]]
exceeds 2 hours in which case refrigeration of the sample is
recommended.
9.0 Quality Control
9.1 For each sample type, 12 samples of SBR latex shall be obtained
from the process for the recovery study. Half the vials and caps shall
be tared, labeled ``spiked'', and numbered 1 through 6. The other vials
are labeled ``unspiked'' and need not be tared, but are also numbered 1
through 6.
9.2 The six vials labeled ``spiked'' shall be spiked with an amount of
styrene to approximate 50% of the solution's expected residual styrene
level.
9.3 The spiked samples shall be shaken for several hours and allowed
to cool to room temperature before analysis.
9.4 The six samples of unspiked solution shall be coagulated and a
mean styrene value shall be determined, along with the standard
deviation, and the percent relative standard deviation.
9.5 The six samples of the spiked solution shall be coagulated and the
results of the analyses shall be determined using the following
equations:
Mr=Ms-Mu
R=Mr/S
where:
Mu=Mean value of styrene in the unspiked sample
Ms=Measured amount of styrene in the spiked sample
Mr=Measured amount of the spiked compound
S=Amount of styrene added to the spiked sample
R=Fraction of spiked styrene recovered
9.6 A value of R between 0.70 and 1.30 is acceptable.
9.7 R is used to correct all reported results for each compound by
dividing the measured results of each compound by the R for that
compound for the same sample type.
10.0 Calibration
10.1 Using a 10-ml volumetric pipet, quantitatively transfer 10.0 ml
of the STYRENE WORKING SOLUTION (section 7.7.2 of this method) into a
2-oz bottle.
10.2 Using the AMS WORKING SOLUTION equipped with the automatic
dispensing pipet (section 7.5.3 of this method), transfer 50.0 ml of
the internal standard solution into the 2-oz bottle.
10.3 Cap the 2-oz bottle and swirl. This is the calibration standard,
which contains 5000 g of styrene and 2500 g of AMS.
10.4 Using the conditions prescribed (section 6.5 of this method),
chromatograph 1 l of the calibration standard.
10.5 Obtain the peak areas and calculate the relative response factor
as described in the calculations section (section 12.1 of this method).
11.0 Procedure
11.1 Into a tared 2-oz bottle, weigh 10.0 g of latex to the nearest
0.1 g.
11.2 Using the AMS WORKING SOLUTION equipped with the automatic
dispensing pipet (section 7.5.3 of this method), transfer 50.0 ml of
the internal standard solution into the 2-oz bottle.
11.3 Cap the bottle. Using a mechanical shaker, shake the bottle for
at least one minute or until coagulation of the latex is complete as
indicated by a clear solvent.
11.4 Using the conditions prescribed (section 6.5 of this method),
chromatograph 1 ul of the liquor.
11.5 Obtain the peak areas and calculate the concentration of styrene
in the latex as described in the calculations section (Section 12.2 of
this method).
12.0 Calculations
12.1 Calibration:
RF=(Wx x Ais) / (Wis x Ax)
where:
RF=the relative response factor for styrene
Wx=the weight (ug) of styrene
Ais=the area of AMS
Wis=the weight (ug) of AMS
Ax=the area of styrene
12.2 Procedure:
ppmstyrene=(AxRF x Wis) / (Ais x Ws)
where:
ppmstyrene=parts per million of styrene in the latex
Ax=the area of styrene
RF=the response factor for styrene
Wis=the weight (ug) of AMS
Ais=the area of AMS
Ws=the weight (g) of the latex sample
12.3 Correct for recovery (R) as determined by section 9.0 of this
method.
13.0 Precision
13.1 Precision for the method was determined at the 80, 144, 590, and
1160 ppm levels. The standard deviations were 0.8, 1.5, 5 and 9 ppm
respectively. The percent relative standard deviations (%RSD) were 1%
or less at all levels. Five degrees of freedom were used for all
precision data except at the 80 ppm level, where nine degrees of
freedom were used. Note: These are example results and do not replace
quality assurance procedures in this method.
14.0 Pollution Prevention
14.1 Waste generation should be minimized where possible. Sample size
should be an amount necessary to adequately run the analysis.
15.0 Waste Management
15.1 Discard liquid chemical waste into the chemical waste drum.
15.2 Discard latex sample waste into the latex waste drum.
15.3 Discard polymer waste into the polymer waste container.
16.0 References
16.1 This method is based on Goodyear Chemical Division Test Method E-
889.
METHOD 312C--DETERMINATION OF RESIDUAL STYRENE IN SBR LATEX PRODUCED BY
EMULSION POLYMERIZATION
1.0 Scope
1.1 This method is applicable for determining the amount of residual
styrene in SBR latex as produced in the emulsion polymerization
process.
2.0 Principle of Method
2.1 A weighed sample of latex is coagulated in 2-propanol which
contains alpha-methyl styrene as an Internal Standard. The extract from
the coagulation will contain the alpha-methyl styrene as the Internal
Standard and the residual styrene from the latex. The extract is
analyzed by a Gas Chromatograph. Percent styrene is calculated by
relating the area of the styrene peak to the area of the Internal
Standard peak of known concentration.
3.0 Definitions
3.1 The definitions are included in the text as needed.
4.0 Interferences
(Reserved)
5.0 Safety
5.1 When using solvents, avoid contact with skin and eyes. Wear hand
and eye protection. Wash thoroughly after use.
5.2 Avoid overexposure to solvent vapors. Handle only in well
ventilated areas.
[[Page 12558]]
6.0 Equipment and Supplies
6.1 Gas Chromatograph--Hewlett Packard 5890, Series II with flame
ionization detector, or equivalent.
Column--HP 19095F-123, 30m x 0.53mm, or equivalent. Substrate HP
FFAP (cross-linked) film thickness 1 micrometer. Glass injector port
liners with silanized glass wool plug.
Integrator--HP 3396, Series II, or equivalent.
6.2 Wrist action shaker
6.3 Automatic dispenser
6.4 Automatic pipet, calibrated to deliver 5.0 0.01 grams
of latex
6.5 Four-ounce wide-mouth bottles with foil lined lids
6.6 Crimp cap vials, 2ml, teflon lined septa
6.7 Disposable pipets
6.8 Qualitative filter paper
6.9 Cap crimper
6.10 Analytical balance
6.11 10ml pipette
6.12 Two-inch funnel
7.0 Reagents and Standards
7.1 2-Propanol (HP2C grade)
7.2 Alpha methyl styrene (99+% purity)
7.3 Styrene (99+% purity)
7.4 Zero air
7.5 Hydrogen (chromatographic grade)
7.6 Helium
7.7 Internal Standard preparation
7.7.1 Weigh 5.000-5.005 grams of alpha-methyl styrene into a 100ml
volumetric flask and bring to mark with 2-propanol to make Stock ``A''
Solution.
Note: Shelf life--6 months.
7.7.2 Pipette 10ml of Stock ``A'' Solution into a 100ml volumetric
flask and bring to mark with 2-propanol to prepare Stock ``B''
Solution.
7.7.3 Pipette 10ml of the Stock ``B'' solution to a 1000ml
volumetric flask and bring to the mark with 2-propanol. This will be
the Internal Standard Solution (0.00005 grams/ml).
7.8 Certification of Internal Standard--Each batch of Stock ``B''
Solution will be certified to confirm concentration.
7.8.1 Prepare a Standard Styrene Control Solution in 2-propanol by
the following method:
7.8.1.1 Weigh 5.000 .005g of styrene to a 100ml
volumetric flask and fill to mark with 2-propanol to make Styrene Stock
``A'' Solution.
7.8.1.2 Pipette 10ml of Styrene Stock ``A'' Solution to a 100ml
volumetric flask and fill to mark with 2-propanol to make Styrene Stock
``B'' Solution.
7.8.1.3 Pipette 10ml of Styrene Stock ``B'' soluion to a 250ml
volumtric flask and fill to mark wtih 2-propanol to make the
Certification Solution.
7.8.2 Certify Alpha-Methyl Styrene Stock ``B'' Solution.
7.8.2.1 Pipette 5ml of the Certification Solution and 25ml of the
Alpha Methyl Styrene Internal Standard Solution to a 4-oz. bottle, cap
and shake well.
7.8.2.2 Analyze the resulting mixture by GC using the residual
styrene method. (11.4-11.6 of this method)
7.8.2.3 Calculate the weight of alpha methyl styrene present in
the 25ml aliquat of the new Alpha Methyl Styrene Standard by the
following equation:
Wx = FxxWis(Ax/Ais)
Where
Ax = Peak area of alpha methyl styrene
Ais = Peak area of styrene
Wx = Weight of alpha methyl styrene
Wis = Weight of styrene (.00100)
Fx = Analyzed response factor = 1
The Alpha Methyl Styrene Stock Solution used to prepare the
Internal Standard Solution may be considered certified if the weight of
alpha methyl styrene analyzed by this method is within the range of
.00121g to .00129g.
8.0 Sampling
8.1 Collect a latex sample in a capped container. Cap the bottle and
identify the sample as to location and time.
8.2 Deliver sample to Laboratory for testing within one hour.
8.3 Laboratory will test within two hours.
8.4 No special storage conditions are required.
9.0 Quality Control
9.1 The laboratory is required to operate a formal quality control
program. This consists of an initial demonstration of the capability of
the method as well as ongoing analysis of standards, blanks, and spiked
samples to demonstrate continued performance.
9.1.1 When the method is first set up, a calibration is run and
the recovery efficiency for each type of sample must be determined.
9.1.2 If new types of samples are being analyzed, then recovery
efficiency for each new type of sample must be determined. New type
includes any change, such as polymer type, physical form or a
significant change in the composition of the matrix.
9.2 Recovery efficiency must be determined once for each sample type
and whenever modifications are made to the method.
9.2.1 In determining the recovery efficiency, the quadruplet
sampling system shall be used. Six sets of samples (for a total of 24)
shall be taken. In each quadruplet set, half of the samples (two out of
the four) shall be spiked with styrene.
9.2.2 Prepare the samples as described in section 8 of this method.
To the vials labeled ``spiked'', add a known amount of styrene that is
expected to be present in the latex.
9.2.3 Run the spiked and unspiked samples in the normal manner.
Record the concentrations of styrene reported for each pair of spiked
and unspiked samples with the same vial number.
9.2.4 For each hydrocarbon, calculate the average recovery
efficiency (R) using the following equation:
R=(Rn)/12
Where: n = sample number
Rn=(Ms-Mu)/S
Ms=total mass of compound (styrene) measured in spiked sample
(g)
Mu=total mass of compound (styrene) measured in unspiked sample
(g)
S=theoretical mass of compound (styrene) spiked into sample
(g)
R=fraction of spiked compound (styrene) recovered
9.2.5 A different R value should be obtained for each sample type. A
value of R between 0.70 and 1.30 is acceptable.
9.2.6 R is used to correct all reported results for each compound by
dividing the measured results of each compound by the R for that
compound for the same sample type.
10.0 Calibration
A styrene control sample will be tested weekly to confirm the FID
response and calibration.
10.1 Using the Styrene Certification Solution prepared in 7.8.1,
perform test analysis as described in 7.8.2 using the equation in
7.8.2.3 to calculate results.
10.2 Calculate the weight of styrene in the styrene control sample
using the following equation:
Wsty=(FxxAstyxWis)Ais
The instrument can be considered calibrated if the weight of the
styrene analyzed is within range of 0.00097--0.00103gms.
[[Page 12559]]
11.0 Procedure
11.1 Using an auto pipet, add 25ml of Internal Standard Solution to a
4 oz. wide-mouth bottle.
11.2 Using a calibrated auto pipet, add 5.0 0.01g latex
to the bottle containing the 25ml of Internal Standard Solution.
11.3 Cap the bottle and place on the wrist action shaker. Shake the
sample for a minimum of five minutes using the timer on the shaker.
Remove from shaker.
11.4 Using a disposable pipet, fill the 2ml sample vial with the clear
alcohol extract. (If the extract is not clear, it should be filtered
using a funnel and filter paper.) Cap and seal the vial.
11.5 Place the sample in the autosampler tray and start the GC and
Integrator. The sample will be injected into the GC by the auto-
injector, and the Integrator will print the results.
11.6 Gas Chromatograph Conditions
Oven Temp--70 deg.C
Injector Temp--225 deg.C
Detector Temp--275 deg.C
Helium Pressure--500 KPA
Column Head Pressure--70 KPA
Makeup Gas--30 ml/min.
Column--HP 19095F--123, 30m x 0.53mm Substrate: HP--FFAP (cross-
linked) 1 micrometer film thickness
12.0 Calculations
12.1 The integrator is programmed to do the following calculation at
the end of the analysis:
%ResidualStyrene=(AxXWis)/(AisXWx)XFxX100
Where:
Ax=Peak area of styrene
Ais=Peak area of internal standard
Wx=Weight of sample = 5g
Wis=Weight of internal std. = 0.00125g
Fx=Analyzed response factor = 1.0
12.2 The response factor is determined by analyzing a solution of
0.02g of styrene and 0.02g of alpha methyl styrene in 100ml of 2-
propanol. Calculate the factor by the following equation:
Fx=(WxxAis)/(WisxAx)
Where:
Wx=Weight of styrene
Ax=Peak area of styrene
Wis=Weight of alpha methyl styrene
Ais=Peak area of alpha methyl styrene
13.0 Method Performance
13.1 Performance must be determined for each sample type by following
the procedures in section 9 of this method.
14.0 Waste Generation
14.1 Waste generation should be minimized where possible.
15.0 Waste Management
15.1 All waste shall be handled in accordance with Federal and State
environmental regulations.
16.0 References
(Reserved)
METHOD 313A--DETERMINATION OF RESIDUAL HYDROCARBONS IN RUBBER CRUMB
1.0 Scope and Application
1.1 This method determines residual toluene and styrene in
stripper crumb of the of the following types of rubber: polybutadiene
(PBR) and styrene/butadiene rubber (SBR), both derived from solution
polymerization processes that utilize toluene as the polymerization
solvent.
1.2 The method is applicable to a wide range of concentrations of
toluene and styrene provided that calibration standards cover the
desired range. It is applicable at least over the range of 0.01 to 10.0
% residual toluene and from 0.1 to 3.0 % residual styrene. It is
probably applicable over a wider range, but this must be verified prior
to use.
1.3 The method may also be applicable to other process samples as
long as they are of a similar composition to stripper crumb. See
section 3.1 of this method for a description of stripper crumb.
2.0 Summary of Method
2.1 The wet crumb is placed in a sealed vial and run on a
headspace sampler which heats the vial to a specified temperature for a
specific time and then injects a known volume of vapor into a capillary
GC. The concentration of each component in the vapor is proportional to
the level of that component in the crumb sample and does not depend on
water content of the crumb.
2.2 Identification of each component is performed by comparing the
retention times to those of known standards.
2.3 Results are calculated by the external standard method since
injections are all performed in an identical manner. The response for
each component is compared with that obtained from dosed samples of
crumb.
2.4 Measured results of each compound are corrected by dividing
each by the average recovery efficiency determined for the same
compound in the same sample type.
3.0 Definitions
3.1 Stripper crumb refers to pieces of rubber resulting from the
steam stripping of a toluene solution of the same polymer in a water
slurry. The primary component of this will be polymer with lesser
amounts of entrained water and residual toluene and other hydrocarbons.
The amounts of hydrocarbons present must be such that the crumb is a
solid material, generally less that 10 % of the dry rubber weight.
4.0 Interferences
4.1 Contamination is not normally a problem since samples are
sealed into vials immediately on sampling.
4.2 Cross contamination in the headspace sampler should not be a
problem if the correct sampler settings are used. This should be
verified by running a blank sample immediately following a normal or
high sample. Settings may be modified if necessary if this proves to be
a problem, or a blank sample may be inserted between samples.
4.3 Interferences may occur if volatile hydrocarbons are present
which have retention times close to that of the components of interest.
Since the solvent makeup of the processes involved are normally fairly
well defined this should not be a problem. If it is found to be the
case, switching to a different chromatographic column will probably
resolve the situation.
5.0 Safety
5.1 The chemicals specified in this method should all be handled
according to standard laboratory practices as well as any special
precautions that may be listed in the MSDS for that compound.
5.2 Sampling of strippers or other process streams may involve
high pressures and temperatures or may have the potential for exposure
to chemical fumes. Only personnel who have been trained in the specific
sampling procedures required for that process should perform this
operation. An understanding of the process involved is necessary.
Proper personal protective equipment should be worn. Any sampling
devices should be inspected prior to use. A detailed sampling procedure
which specifies exactly how to obtain the sample must be written and
followed.
6.0 Equipment and Supplies
6.1 Hewlett Packard (HP) 7694 Headspace sampler, or equivalent,
with the following conditions:
Times (min.): GC cycle time 6.0 , vial equilibration 30.0 ,
pressurization 0.25 , loop fill 0.25, loop equilibration 0.05 , inject
0.25
Temperatures (deg C): oven 70, loop 80, transfer line 90
Pressurization gas: He @ 16 psi
[[Page 12560]]
6.2 HP 5890 Series II capillary gas chromatograph, or equivalent,
with the following conditions:
Column: Supelco SPB-1, or equivalent, 15m x .25mm x .25
film
Carrier: He @ 6 psi
Run time: 4 minutes
Oven: 70 deg C isothermal
Injector: 200 deg C split ratio 50:1
Detector: FID @ 220 deg C
6.3 HP Chemstation consisting of computer, printer and Chemstation
software, or an equivalent chromatographic data system.
6.4 20 ml headspace vials with caps and septa.
6.5 Headspace vial crimper.
6.6 Microliter pipetting syringes.
6.7 Drying oven at 100 deg C vented into cold trap or other means
of trapping hydrocarbons released.
6.8 Laboratory shaker or tumbler suitable for the headspace vials.
6.9 Personal protective equipment required for sampling the
process such as rubber gloves and face and eye protection.
7.0 Reagents and Standards
7.1 Toluene, 99.9+% purity, HPLC grade.
7.2 Styrene, 99.9+% purity, HPLC grade.
7.3 Dry rubber of same type as the stripper crumb samples.
8.0 Sample Collection, Preservation and Storage
8.1 Collect a sample of crumb in a manner appropriate for the
process equipment being sampled.
8.1.1 If conditions permit, this may be done by passing a stream
of the crumb slurry through a strainer, thus separating the crumb from
the water. Allow the water to drain freely, do not attempt to squeeze
any water from the crumb. Results will not depend on the exact water
content of the samples. Immediately place several pieces of crumb
directly into a headspace vial. This should be done with rubber gloves
to protect the hands from both the heat and from contact with residual
hydrocarbons. The vial should be between \1/4\ and \1/3\ full. Results
do not depend on sample size as long as there is sufficient sample to
reach an equilibrium vapor pressure in the headspace of the vial. Cap
and seal the vial. Prepare each sample at least in duplicate. This is
to minimize the effect of the variation that naturally occurs in the
composition of non homogeneous crumb. The free water is not analyzed by
this method and should be disposed of appropriately along with any
unused rubber crumb.
8.1.2 Alternatively the process can be sampled in a specially
constructed sealed bomb which can then be transported to the
laboratory. The bomb is then cooled to ambient temperature by applying
a stream of running water. The bomb can then be opened and the crumb
separated from the water and the vials filled as described in section
8.1.1 of this method. The bomb may be stored up to 8 hours prior to
transferring the crumb into vials.
8.2 The sealed headspace vials may be run immediately or may be
stored up to 72 hours prior to running. It is possible that even longer
storage times may be acceptable, but this must be verified for the
particular type of sample being analyzed (see section 9.2.3 of this
method). The main concern here is that some types of rubber eventually
may flow, thus compacting the crumb so that the surface area is
reduced. This may have some effect on the headspace equilibration.
9.0 Quality Control
9.1 The laboratory is required to operate a formal quality control
program. This consists of an initial demonstration of the capability of
the method as well as ongoing analysis of standards, blanks and spiked
samples to demonstrate continued performance.
9.1.1 When the method is first set up a calibration is run
(described in section 10 of this method) and an initial demonstration
of method capability is performed (described in section 9.2 of this
method). Also recovery efficiency for each type of sample must be
determined (see section 9.4 of this method).
9.1.2 It is permissible to modify this method in order to improve
separations or make other improvements, provided that all performance
specifications are met. Each time a modification to the method is made
it is necessary to repeat the calibration (section 10 of this method),
the demonstration of method performance (section 9.2 of this method)
and the recovery efficiency for each type of sample (section 9.4 of
this method).
9.1.3 Ongoing performance should be monitored by running a spiked
rubber standard. If this test fails to demonstrate that the analysis is
in control, then corrective action must be taken. This method is
described in section 9.3 of this method.
9.1.4 If new types of samples are being analyzed then recovery
efficiency for each new type of sample must be determined. New type
includes any change, such as polymer type, physical form or a
significant change in the composition of the matrix.
9.2 Initial demonstration of method capability to establish the
accuracy and precision of the method. This is to be run following the
calibration described in section 10 of this method.
9.2.1 Prepare a series of identical spiked rubber standards as
described in section 9.3 of this method. A sufficient number to
determine statistical information on the test should be run. Ten may be
a suitable number, depending on the quality control methodology used at
the laboratory running the tests. These are run in the same manner as
unknown samples (see section 11 of this method).
9.2.2 Determine mean and standard deviation for the results. Use
these to determine the capability of the method and to calculate
suitable control limits for the ongoing performance check which will
utilize the same standards.
9.2.3 Prepare several additional spiked rubber standards and run 2
each day to determine the suitability of storage of the samples for 24,
48 and 72 hours or longer if longer storage times are desired.
9.3 A spiked rubber standard should be run on a regular basis to
verify system performance. This would probably be done daily if samples
are run daily. This is prepared in the same manner as the calibration
standards (section 10.1 of this method), except that only one
concentration of toluene and styrene is prepared. Choose concentrations
of toluene and styrene that fall in the middle of the range expected in
the stripper crumb and then do not change these unless there is a major
change in the composition of the unknowns. If it becomes necessary to
change the composition of this standard the initial performance
demonstration must be repeated with the new standard (section 9.2 of
this method).
9.3.1 Each day prepare one spiked rubber standard to be run the
following day. The dry rubber may be prepared in bulk and stored for
any length of time consistent with the shelf life of the product. The
addition of water and hydrocarbons must be performed daily and all the
steps described under section 10.1 of this method must be followed.
9.3.2 Run the spiked rubber standard prepared the previous day.
Record the results and plot on an appropriate control chart or other
means of determining statistical control.
9.3.3 If the results for the standard indicate that the test is
out of control then corrective action must be taken. This may include a
check on procedures, instrument settings, maintenance or recalibration.
Samples may be stored (see section 8.2 of this
[[Page 12561]]
method) until compliance is demonstrated.
9.4 Recovery efficiency must be determined once for each sample
type and whenever modifications are made to the method.
9.4.1 For each sample type collect 12 samples from the process
(section 8.1 of this method). This should be done when the process is
operating in a normal manner and residual hydrocarbon levels are in the
normal range. Half the vials and caps should be tared, labeled
``spiked'' and numbered 1 through 6. The other vials are labeled
``unspiked'' and need not be tared but are also numbered 1 through 6.
Immediately on sampling, the vials should be capped to prevent loss of
volatiles. Allow all the samples to cool completely to ambient
temperature. Reweigh each of the vials labeled ``spiked'' to determine
the weight of wet crumb inside.
9.4.2 The dry weight of rubber present in the wet crumb is
estimated by multiplying the weight of wet crumb by the fraction of
nonvolatiles typical for the sample. If this is not known, an
additional quantity of crumb may be sampled, weighed, dried in an oven
and reweighed to determine the fraction of volatiles and nonvolatiles
prior to starting this procedure.
9.4.3 To the vials labeled ``spiked'' add an amount of a mixture
of toluene and styrene that is between 40 and 60 % of the amount
expected in the crumb. This is done by removing the cap, adding the
mixture by syringe, touching the tip of the needle to the sample in
order to remove the drop and then immediately recapping the vials. The
mixture is not added through the septum, because a punctured septum may
leak and vent vapors as the vial is heated. The weights of toluene and
styrene added may be calculated from the volumes of the mixture added,
its composition and density, or may be determined by the weight of the
vials and caps prior to and after addition. The exact dry weight of
rubber present and the concentration of residual toluene and styrene
are not known at this time so an exact calculation of the concentration
of hydrocarbons is not possible until the test is completed.
9.4.4 Place all the vials onto a shaker or tumbler for 24
2 hours. This is essential in order for the hydrocarbons
to be evenly distributed and completely absorbed into the rubber. If
this is not followed the toluene and styrene will be mostly at the
surface of the rubber and high results will be obtained.
9.4.5 Remove the vials from the shaker and tap them so that all
the crumb settles to the bottom of the vials. Allow them to stand for 1
hour prior to analysis to allow any liquid to drain fully to the
bottom.
9.4.6 Run the spiked and unspiked samples in the normal manner.
Record the concentrations of toluene and styrene reported for each pair
of spiked and unspiked samples with the same vial number.
9.4.7 Open each of the vials labeled ``spiked'', remove all the
rubber crumb and place it into a tarred drying pan. Place in a 100 deg
C oven for two hours, cool and reweigh. Subtract the weight of the tare
to give the dry weight of rubber in each spiked vial. Calculate the
concentration of toluene and styrene spiked into each vial as percent
of dry rubber weight. This will be slightly different for each vial
since the weights of dry rubber will be different.
9.4.8 For each hydrocarbon calculate the average recovery
efficiency (R) using the following equations:
R=R__ (n)/6 (average of the 6 individual
Rn values)
Where:
Rn=(Cns--Cnu) / Sn
Where:
n=vial number
Cns=concentration of compound measured in spiked sample number n.
Cnu=concentration of compound measured in unspiked sample number n.
Sn=theoretical concentration of compound spiked into sample n
calculated in step 9.4.7
9.4.9 A different R value should be obtained for each compound
(styrene and toluene) and for each sample type.
9.4.10 A value of R between 0.70 and 1.30 is acceptable.
9.4.11 R is used to correct all reported results for each compound
by dividing the measured results of each compound by the R for that
compound for the same sample type (see section 12.2 of this method.)
10.0 Calibration
10.1 Calibration standards are prepared by dosing known amounts of
the hydrocarbons of interest into vials containing known amounts of
rubber and water.
10.1.1 Cut a sufficient quantity of dry rubber of the same type as
will be analyzed into pieces about the same size as that of the crumb.
Place these in a single layer on a piece of aluminum foil or other
suitable surface and place into a forced air oven at 100 deg. C for
four hours. This is to remove any residual hydrocarbons that may be
present. This step may be performed in advance.
10.1.2 Into each of a series of vials add 3.0 g of the dry rubber.
10.1.3 Into each vial add 1.0 ml distilled water or an amount that
is close to the amount that will be present in the unknowns. The exact
amount of water present does not have much effect on the analysis, but
it is necessary to have a saturated environment. The water will also
aid in the uniform distribution of the spiked hydrocarbons over the
surface of the rubber after the vials are placed on the shaker (in step
10.1.5 of this method).
10.1.4 Into each vial add varying amounts of toluene and styrene
by microliter syringe and cap the vials immediately to prevent loss.
The tip of the needle should be carefully touched to the rubber in
order to transfer the last drop to the rubber. Toluene and styrene may
first be mixed together in suitable proportions and added together if
desired. The weights of toluene and styrene added may be calculated
from the volumes of the mixture added, its composition and density, or
may be determined by the weight of the vials and caps prior to and
after addition. Concentrations of added hydrocarbons are calculated as
percent of the dry rubber weight. At least 5 standards should be
prepared with the amounts of hydrocarbons added being calculated to
cover the entire range possible in the unknowns. Retain two samples
with no added hydrocarbons as blanks.
10.1.5 Place all the vials onto a shaker or tumbler for 24
2 hours. This is essential in order for the hydrocarbons
to be evenly distributed and completely absorbed into the rubber. If
this is not followed the toluene and styrene will be mostly at the
surface of the rubber and high results will be obtained.
10.1.6 Remove the vials from the shaker and tap them so that all
the crumb settles to the bottom of the vials. Allow them to stand for 1
hour prior to analysis to allow any liquid to drain fully to the
bottom.
10.2 Run the standards and blanks in the same manner as described
for unknowns (section 11 of this method), starting with a blank, then
in order of increasing hydrocarbon content and ending with the other
blank.
10.3 Verify that the blanks are sufficiently free from toluene and
styrene or any interfering hydrocarbons.
10.3.1 It is possible that trace levels may be present even in dry
product. If levels are high enough that they will interfere with the
calibration then the drying procedure in section 10.1.1 of this method
should be reviewed and modified as needed to ensure that suitable
standards can be prepared.
10.3.2 It is possible that the final blank is contaminated by the
previous
[[Page 12562]]
standard. If this is the case review and modify the sampler parameters
as needed to eliminate this problem. If necessary it is possible to run
blank samples between regular samples in order to reduce this problem,
though it should not be necessary if the sampler is properly set up.
10.4 Enter the amounts of toluene and styrene added to each of the
samples (as calculated in section 10.1.4 of this method) into the
calibration table and perform a calibration utilizing the external
standard method of analysis.
10.5 At low concentrations the calibration should be close to
linear. If a wide range of levels are to be determined it may be
desirable to apply a nonlinear calibration to get the best fit.
11.0 Procedure
11.1 Place the vials in the tray of the headspace sampler. Enter
the starting and ending positions through the console of the sampler.
For unknown samples each is run in duplicate to minimize the effect of
variations in crumb composition. If excessive variation is noted it may
be desirable to run more than two of each sample.
11.2 Make sure the correct method is loaded on the Chemstation.
Turn on the gas flows and light the FID flame.
11.3 Start the sequence on the Chemstation. Press the START button
on the headspace unit. The samples will be automatically injected after
equilibrating for 30 minutes in the oven. As each sample is completed
the Chemstation will calculate and print out the results as percent
toluene and styrene in the crumb based on the dry weight of rubber.
12.0 Data Analysis and Calculations
12.1 For each set of duplicate samples calculate the average of
the measured concentration of toluene and styrene. If more than two
replicates of each sample are run calculate the average over all
replicates.
12.2 For each sample correct the measured amounts of toluene and
styrene using the following equation:
Corrected Result = Cm/R
Where:
Cm = Average measured concentration for that compound.
R = Recovery efficiency for that compound in the same sample type (see
section 9.4 of this method)
12.3 Report the recovery efficiency (R) and the corrected results
of toluene and styrene for each sample.
13.0 Method Performance
13.1 This method can be very sensitive and reproducible. The
actual performance depends largely on the exact nature of the samples
being analyzed. Actual performance must be determined by each
laboratory for each sample type.
13.2 The main source of variation is the actual variation in the
composition of non homogeneous crumb in a stripping system and the
small sample sizes employed here. It therefore is the responsibility of
each laboratory to determine the optimum number of replicates of each
sample required to obtain accurate results.
14.0 Pollution Prevention
14.1 Samples should be kept sealed when possible in order to
prevent evaporation of hydrocarbons.
14.2 When drying of samples is required it should be done in an
oven which vents into a suitable device that can trap the hydrocarbons
released.
14.3 Dispose of samples as described in section 15.
15.0 Waste Management
15.1 Excess stripper crumb and water as well as the contents of
the used sample vials should be properly disposed of in accordance with
local and federal regulations.
15.2 Preferably this will be accomplished by having a system of
returning unused and spent samples to the process.
16.0 References
16.1 ``HP 7694 Headspace Sampler--Operating and Service Manual'',
Hewlett-Packard Company, publication number G1290-90310, June 1993.
METHOD 313B--THE DETERMINATION OF RESIDUAL HYDROCARBON IN SOLUTION
POLYMERS BY CAPILLARY GAS CHROMATOGRAPHY
1.0 Scope
1.1 This method is applicable to solution polymerized
polybutadiene (PBD).
1.2 This method quantitatively determines n-hexane in wet crumb
polymer at levels from 0.08 to 0.15% by weight.
1.3 This method may be extended to the determination of other
hydrocarbons in solution produced polymers with proper experimentation
and documentation.
2.0 Principle of Method
2.1 A weighed sample of polymer is dissolved in chloroform and the
cement is coagulated with an isopropyl alcohol solution containing a
specific amount of alpha-methyl styrene (AMS) as the internal standard.
The extract of this coagulation is then injected into a gas
chromatograph and separated into individual components. Quantification
is achieved by the method of internal standardization.
3.0 Definitions
3.1 The definitions are included in the text as needed.
4.0 Interferences
(Reserved)
5.0 Safety
5.1 This method may involve hazardous materials, operations, and
equipment. This method does not purport to address all of the safety
problems associated with its use. It is the responsibility of the user
of this method to establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use.
6.0 Equipment and Supplies
6.1 Analytical balance, 160 g capacity, 0.1 mg resolution
6.2 Bottles, 2-oz capacity with poly-cap screw lids
6.3 Mechanical shaker
6.4 Syringe, 10-ul capacity
6.5 Syringe, 2.5-ml capacity, with 22 gauge 1.25 inch needle, PP/PE
material, disposable
6.6 Gas chromatograph, Hewlett-Packard model 5890, or equivalent,
configured with FID, split injector packed with silanized glass wool.
6.6.1 Establish the following gas chromatographic conditions, and
allow the system to thoroughly equilibrate before use.
6.6.2 Injector parameters:
Injection technique=Split
Injector split flow=86 ml/min
Injector temperature=225 deg C
6.6.3 Oven temperature program:
Initial temperature=40 deg C
Initial time=6 min
Program rate=10 deg C/min
Upper limit temperature=175 deg C
Upper limit interval=10 min
6.6.4 Detector parameters:
Detector temperature=300 deg C
Hydrogen flow=30 ml/min
Air flow=350 ml/min
Nitrogen make up=26 ml/min
6.7 Gas chromatographic columns: SE-54 (5%-phenyl) (1%-vinyl)-
methylpolysiloxane, 15 M x 0.53 mm ID with a 1.2 micron film thickness,
and a Carbowax 20M (polyethylene glycol), 15 M x 0.53 mm ID with a 1.2
micron film thickness.
6.7.1 Column assembly: using a 0.53 mm ID butt connector union,
join the 15 M x 0.53 mm SE-54 column
[[Page 12563]]
to the 15 M x 0.53 mm Carbowax 20M. The SE-54 column will be inserted
into the injector and the Carbowax 20M inserted into the detector after
they have been joined.
6.7.2 Column parameters:
Helium flow=2.8 ml/min
Helium headpressure=2 psig
6.8 Centrifuge
6.9 Data collection system, Hewlett-Packard Model 3396, or equivalent
6.10 Pipet, 25-ml capacity, automatic dispensing, and 2 liter
reservoir
6.11 Pipet, 2-ml capacity, volumetric delivery, class A
6.12 Flasks, 100 and 1000-ml capacity, volumetric, class A
6.13 Vial, serum, 50-ml capacity, red rubber septa and crimp ring
seals
6.14 Sample collection basket fabricated out of wire mesh to allow for
drainage
7.0 Chemicals and Reagents
CHEMICALS:
7.1 alpha-Methyl Styrene, C9H10, 99+% purity, CAS 98-83-9
7.2 n-Hexane, C6H14, 99+% purity, CAS 110-54-3
7.3 Isopropyl alcohol, C3H8O 99.5+% purity, reagent grade, CAS 67-63-0
7.4 Chloroform, CHCl3, 99% min., CAS 67-66-3
REAGENTS:
7.5 Internal Standard Stock Solution: 10 mg/25 ml AMS in isopropyl
alcohol.
7.5.1 Into a 25-ml beaker, weigh 0.4 g of AMS to the nearest 0.1
mg.
7.5.2 Quantitatively transfer this AMS into a 1-L volumetric
flask. Dilute to the mark with isopropyl alcohol.
7.5.3 Transfer this solution to the automatic dispensing pipet
reservoir. This will be labeled the AMS STOCK SOLUTION.
7.6 n-Hexane Stock Solution: 13mg/2ml hexane in isopropyl alcohol.
7.6.1 Into a 100-ml volumetric flask, weigh 0.65 g of n-hexane to
the nearest 0.1 mg.
7.6.2 Dilute to the mark with isopropyl alcohol. This solution
will be labeled the n-HEXANE STOCK SOLUTION.
8.0 Sample Collection, Preservation and Storage
8.1 A sampling device similar to Figure 1 is used to collect a non-
vented crumb rubber sample at a location that is after the stripping
operation but before the sample is exposed to the atmosphere.
8.2 The crumb rubber is allowed to cool before opening the sampling
device and removing the sample.
8.3 The sampling device is opened and the crumb rubber sample is
collected in the sampling basket.
8.4 One pound of crumb rubber sample is placed into a polyethylene
bag. The bag is labeled with the time, date and sample location.
8.5 The sample should be delivered to the laboratory for testing
within one hour of sampling.
8.6 Laboratory testing will be done within 3 hours of the sampling
time.
8.7 No special storage conditions are required unless the storage time
exceeds 3 hours in which case refrigeration of the samples is
recommended.
9.0 Quality Control
9.1 For each sample type, 12 samples shall be obtained from the
process for the recovery study. Half of the vials and caps shall be
tared, labeled ``spiked'', and numbered 1 through 6. The other vials
shall be labeled ``unspiked'' and need not be tared, but are also
numbered 1 through 6.
9.2 Determine the % moisture content of the crumb sample. After
determining the % moisture content, the correction factor for
calculating the dry crumb weight can be determined by using the
equation in section 12.2 of this method.
9.3 Run the spiked and unspiked samples in the normal manner. Record
the concentrations of the n-hexane content of the mixed hexane reported
for each pair of spiked and unspiked samples.
9.4 For the recovery study, each sample of crumb shall be dissolved in
chloroform containing a known amount of mixed hexane solvent.
9.5 For each hydrocarbon, calculate the recovery efficiency (R) using
the following equations:
Mr=Ms-Mu
R=Mr/S
Where:
Mu=Measured amount of compound in the unspiked sample
Ms=Measured amount of compound in the spiked sample
Mr=Measured amount of the spiked compound
S=Amount of compound added to the spiked sample
R=Fraction of spiked compound recovered
9.6 Normally a value of R between 0.70 and 1.30 is acceptable.
9.7 R is used to correct all reported results for each compound by
dividing the measured results of each compound by the R for that
compound for the same sample type.
10.0 Calibration
10.1 Using the AMS STOCK SOLUTION equipped with the automatic
dispensing pipet (7.5.3 of this method), transfer 25.0 ml of the
internal standard solution into an uncapped 50-ml serum vial.
10.2 Using a 2.0 ml volumetric pipet, quantitatively transfer 2.0 ml
of the n-HEXANE STOCK SOLUTION (7.6.2 of this method) into the 50-ml
serum vial and cap. This solution will be labeled the CALIBRATION
SOLUTION.
10.3 Using the conditions prescribed (6.6 of this method), inject 1
l of the supernate.
10.4 Obtain the peak areas and calculate the response factor as
described in the calculations section (12.1 of this method).
11.0 Procedure
11.1 Determination of Dry Polymer Weight
11.1.1 Remove wet crumb from the polyethylene bag and place on
paper towels to absorb excess surface moisture.
11.1.2 Cut small slices or cubes from the center of the crumb
sample to improve sample uniformity and further eliminate surface
moisture.
11.1.3 A suitable gravimetric measurement should be made on a
sample of this wet crumb to determine the correction factor needed to
calculate the dry polymer weight.
11.2 Determination of n-Hexane in Wet Crumb
11.2.1 Remove wet crumb from the polyethylene bag and place on
paper towels to absorb excess surface moisture.
11.2.2 Cut small slices or cubes from the center of the crumb
sample to improve sample uniformity and further eliminate surface
moisture.
11.2.3 Into a tared 2 oz bottle, weigh 1.5 g of wet polymer to the
nearest 0.1 mg.
11.2.4 Add 25 ml of chloroform to the 2 oz bottle and cap.
11.2.5 Using a mechanical shaker, shake the bottle until the
polymer dissolves.
11.2.6 Using the autodispensing pipet, add 25.0 ml of the AMS
STOCK SOLUTION (7.5.3 of this method) to the dissolved polymer solution
and cap.
11.2.7 Using a mechanical shaker, shake the bottle for 10 minutes
to
[[Page 12564]]
coagulate the dissolved polymer.
11.2.8 Centrifuge the sample for 3 minutes at 2000 rpm.
11.2.9 Using the conditions prescribed (6.6 of this method),
chromatograph 1 l of the supernate.
11.2.10 Obtain the peak areas and calculate the concentration of
the component of interest as described in the calculations (12.2 of
this method).
12.0 Calculations
12.1 Calibration:
RFx=(Wx x Ais) / (Wis x Ax)
Where:
RFx=the relative response factor for n-hexane
Wx=the weight (g) of n-hexane in the CALIBRATION
SOLUTION
Ais=the area of AMS
Wis=the weight (g) of AMS in the CALIBRATION SOLUTION
Ax=the area of n-hexane
12.2 Procedure:
12.2.1 Correction Factor for calculating dry crumb weight.
F=1--(% moisture / 100)
Where:
F=Correction factor for calculating dry crumb weight
% moisture determined by appropriate method
12.2.2 Moisture adjustment for chromatographic determination.
Ws=F x Wc
Where:
Ws=the weight (g) of the dry polymer corrected for moisture
F=Correction factor for calculating dry crumb weight
Wc=the weight (g) of the wet crumb in section 9.6
12.2.3 Concentration (ppm) of hexane in the wet crumb.
ppmx=(Ax * RFx * Wis * 10000) / (Ais *
Ws)
Where:
ppmx=parts per million of n-hexane in the polymer
Ax=the area of n-hexane
RFx=the relative response factor for n-hexane
Wis=the weight (g) of AMS in the sample solution
Ais=the area of AMS
Ws=the weight (g) of the dry polymer corrected for moisture
13.0 Method Performance
13.1 Precision for the method was determined at the 0.08% level.
The standard deviation was 0.01 and the percent relative standard
deviation (RSD) was 16.3 % with five degrees of freedom.
14.0 Waste Generation
14.1 Waste generation should be minimized where possible.
15.0 Waste Management
15.1 Discard liquid chemical waste into the chemical waste drum.
15.2 Discard polymer waste into the polymer waste container.
16.0 References
16.1 This method is based on Goodyear Chemical Division Test Method E-
964.
[FR Doc. 97-6506 Filed 3-14-97; 8:45 am]
BILLING CODE 6560-50-P