[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 
<greek-m>l of fresh hexane and 20 <greek-m>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 <greek-m>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 <greek-m>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:

ppm<INF>hexane=(A<INF>hexane x R<INF>hexane)/(A<INF>is x R<INF>is)

Where:
A<INF>hexane=area of hexane
R<INF>hexane=response of hexane
A<INF>is=area of the internal standard
R<INF>is=response of the internal standard
% hexane in crumb=(ppm<INF>hexane/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

----------------------------------------------------------------------------------------------------------------
                                                                                       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%.                 
----------------------------------------------------------------------------------------------------------------

    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, .45<greek-m>m 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 C<INF>6 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 C<INF>6 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 <difference>10g); (gives a dry wt of 
<difference>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=(A<INF>IS  x  C<INF>HS  x  P<INF>HS)/(A<INF>HS  x  C<INF>IS  x  
P<INF>IS)    (1)

Where:
A <INF>IS=Area of IS peak (Heptane)
A<INF>HS=Area of peak (Hexane Standard)
C<INF>HS=Mg of Hexane/50 ml HS
C<INF>IS=Mg of Heptane/50 ml IS Solution B
P<INF>IS=Purity of the IS n-heptane
P<INF>HS=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=(A<INF>s X RF X C<INF>IS X P<INF>IS)/(A<INF>IS X 
SW)  (4)
Where:
A<INF>s=Area of sample hexane sample peak.
A<INF>IS=Area of IS peak in sample.
C<INF>IS=Concentration of IS in 50 ml.
P<INF>IS=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-<greek-m>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 10<greek-m>l 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=<greek-S>(R<INF>n)/6

where:
R<INF>n=(c<INF>ns-c<INF>v)/S<INF>n

n=sample number
c<INF>ns=concentration of compound measured in spiked sample number n.
c<INF>nu= concentration of compound measured in unspiked sample number 
n.
S<INF>n=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 <greek-m>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:

M<INF>r=M<INF>s-M<INF>u
R=M<INF>r/S

where:
M<INF>u=Mean value of styrene in the unspiked sample
M<INF>s=Measured amount of styrene in the spiked sample
M<INF>r=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 <greek-m>g of styrene and 2500 <greek-m>g of AMS.
10.4  Using the conditions prescribed (section 6.5 of this method), 
chromatograph 1 <greek-m>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=(W<INF>x x A<INF>is) / (W<INF>is x A<INF>x)

where:
RF=the relative response factor for styrene
W<INF>x=the weight (ug) of styrene
A<INF>is=the area of AMS
W<INF>is=the weight (ug) of AMS
A<INF>x=the area of styrene
12.2  Procedure:

ppm<INF>styrene=(A<INF>xRF x W<INF>is) / (A<INF>is x W<INF>s)

where:
ppm<INF>styrene=parts per million of styrene in the latex
A<INF>x=the area of styrene
RF=the response factor for styrene
W<INF>is=the weight (ug) of AMS
A<INF>is=the area of AMS
W<INF>s=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 <plus-minus>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 <plus-minus>.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:

W<INF>x = F<INF>xxW<INF>is(A<INF>x/A<INF>is)

Where
A<INF>x = Peak area of alpha methyl styrene
A<INF>is = Peak area of styrene
W<INF>x = Weight of alpha methyl styrene
W<INF>is = Weight of styrene (.00100)
F<INF>x = 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=<greek-S>(R<INF>n)/12
Where: n = sample number
R<INF>n=(M<INF>s-M<INF>u)/S
M<INF>s=total mass of compound (styrene) measured in spiked sample 
(<greek-m>g)
M<INF>u=total mass of compound (styrene) measured in unspiked sample 
(<greek-m>g)
S=theoretical mass of compound (styrene) spiked into sample 
(<greek-m>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:

W<INF>sty=(F<INF>xxA<INF>styxW<INF>is)A<INF>is

    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 <plus-minus> 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=(A<INF>xXW<INF>is)/(A<INF>isXW<INF>x)XF<INF>xX100

Where:
A<INF>x=Peak area of styrene
A<INF>is=Peak area of internal standard
W<INF>x=Weight of sample = 5g
W<INF>is=Weight of internal std. = 0.00125g
F<INF>x=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:

F<INF>x=(W<INF>xxA<INF>is)/(W<INF>isxA<INF>x)
Where:
W<INF>x=Weight of styrene
A<INF>x=Peak area of styrene
W<INF>is=Weight of alpha methyl styrene
A<INF>is=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<greek-m> 
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 
<plus-minus> 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__<greek-S> (<greek-R><INF>n<SUP>)/6 (average of the 6 individual 
R<INF>n <SUP>values)

Where:
R<INF>n<SUP>=(C<INF>ns--C<INF>nu) <SUP>/ S<INF>n

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 
<plus-minus> 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 = C<INF>m/R

Where:
C<INF>m = 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:

M<INF>r=M<INF>s-M<INF>u
R=M<INF>r/S
Where:
M<INF>u=Measured amount of compound in the unspiked sample
M<INF>s=Measured amount of compound in the spiked sample
M<INF>r=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 
<greek-m>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 <greek-m>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:

RF<INF>x=(W<INF>x  x  A<INF>is) / (W<INF>is  x  A<INF>x)

Where:
RF<INF>x=the relative response factor for n-hexane
W<INF>x=the weight (g) of n-hexane in the CALIBRATION
SOLUTION
A<INF>is=the area of AMS
W<INF>is=the weight (g) of AMS in the CALIBRATION SOLUTION
A<INF>x=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.

W<INF>s=F  x  W<INF>c

Where:
W<INF>s=the weight (g) of the dry polymer corrected for moisture
F=Correction factor for calculating dry crumb weight
W<INF>c=the weight (g) of the wet crumb in section 9.6
    12.2.3  Concentration (ppm) of hexane in the wet crumb.

ppm<INF>x=(A<INF>x * RF<INF>x * W<INF>is * 10000) / (A<INF>is * 
W<INF>s)

Where:
ppm<INF>x=parts per million of n-hexane in the polymer
A<INF>x=the area of n-hexane
RF<INF>x=the relative response factor for n-hexane
W<INF>is=the weight (g) of AMS in the sample solution
A<INF>is=the area of AMS
W<INF>s=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