EPA Method 310C Determination Of Residual N-Hexane In Epdm Rubber Through Gas Chromatography
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ID： |
36E9ECDF4D2B44DB85EAF749F597AE82 |
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文件大小(MB)： |
0.01 |
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页数： |
5 |
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文件格式： |
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日期： |
1998-5-13 |
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文本摘录（文本识别可能有误，但文件阅览显示及打印正常，pdf文件可进行文字搜索定位）：
1,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.,2,6.0 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,3,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)X100,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 nhexane,into a 50 ml volumetric flask containing,approximately 40 ml of Solution B. Fill the flas……
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