EPA Method 313A Determination Of Residual Hydrocarbons In Rubber Crumb
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ID： |
2916352AB2A74AAAB3A9158F06992995 |
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文件大小(MB)： |
0.03 |
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页数： |
12 |
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文件格式： |
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日期： |
1998-5-13 |
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购买： |
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）：
Page 1,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.,Page 2,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.,Page 3,5.2 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,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,.25F 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,Page 4,equivalent chromatographic data system.,6.4 20 ml headspace vials with caps and septa.,6.5 Headspace vial crimper.,6.……
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