EPA Method 605 Benzidines
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ID： |
B1D95138146A45E2AA9B263351304F94 |
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文件大小(MB)： |
0.12 |
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页数： |
17 |
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文件格式： |
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日期： |
2003-1-16 |
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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）：
APPENDIX A TO PART 136,METHODS FOR ORGANIC CHEMICAL ANALYSIS OF MUNICIPAL AND,INDUSTRIAL WASTEWATER,METHOD 605—BENZIDINES,1. Scope and Application,1.1 This method covers the determination of certain benzidines. The following parameters,can be determined by this method:,Parameter Storet No. CAS No.,Benzidine . . . . . . . . . . . . . . . . . . . . . 39120 92-87-5,3,3'-Dichlorobenzidine . . . . . . . . . . . . 34631 91-94-1,1.2 This is a high performance liquid chromatography (HPLC) method applicable to the,determination of the compounds listed above in municipal and industrial discharges as,provided under 40 CFR Part 136.1. When this method is used to analyze unfamiliar,samples for the compounds above, identifications should be supported by at least one,additional qualitative technique. This method describes electrochemical conditions at a,second potential which can be used to confirm measurements made with this method.,Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions,appropriate for the qualitative and quantitative confirmation of results for the parameters,listed above, using the extract produced by this method.,1.3 The method detection limit (MDL, defined in Section 14.1)1 for each parameter is listed,in Table 1. The MDL for a specific wastewater may differ from those listed, depending,upon the nature of the interferences in the sample matrix.,1.4 Any modification of this method, beyond those expressly permitted, shall be considered,as a major modification subject to application and approval of alternate test procedures,under 40 CFR Parts 136.4 and 136.5.,1.5 This method is restricted to use by or under the supervision of analysts experienced in,the use of HPLC instrumentation and in the interpretation of liquid chromatograms.,Each analyst must demonstrate the ability to generate acceptable results with this method,using the procedure described in Section 8.2.,2. Summary of Method,2.1 A measured volume of sample, approximately 1-L, is extracted with chloroform using,liquid-liquid extractions in a separatory funnel. The chloroform extract is extracted with,acid. The acid extract is then neutralized and extracted with chloroform. The final,chloroform extract is exchanged to methanol while being concentrated using a rotary,evaporator. The extract is mixed with buffer and separated by HPLC. The benzidine,compounds are measured with an electrochemical detector.2,2.2 The acid back-extraction acts as a general purpose cleanup to aid in the elimination of,interferences.,3. Interferences,3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware,and other sample processing hardware that lead to discrete artifacts and/or elevated,baselines in chromatograms. All of these materials must be routinely demonstrated to,be free from interferences under the conditions of the analysis by running laboratory,reagent blanks as described in Section 8.1.3.,3.1.1 Glassware must be scrupulously cleaned.3 Clean all glassware as soon as possible,after use by rinsing with the last solvent used in it. Solvent rinsing should be,followed by detergent washing with hot water, and rinses with tap water and,distilled water. The glassware should then be drained dry, and heated in a,muffle furnace at 400°C for 15-30 minutes. Some thermally stable materials may,not be eliminated by this treatment. Solvent rinses with acetone and pesticide,quality hexane may be substituted for the muffle furnace heating. Volumetric,ware should not be heated in a muffle furnace. After drying and cooling,glassware should be sealed and stored in a clean environment to prevent any,accumulation of dust or other contaminants. Store inverted or capped with,aluminum foil.,3.1.2 The use of high purity reagents and solvents helps to minimize interference,problems. Purification of solvents by distillation in all-glass systems may be,required.,3.2 Matrix interferences may be caused by contaminants that are co-extracted from the,sample. The extent of matrix interferences will vary considerably from source to source,depending upon the nature and diversity of the industrial complex or municipality being,sampled. The cleanup procedures that are inherent in the extraction step are used to,overcome many of these interferences, but unique samples may require additional,cleanup approaches to achieve the MDL listed in Table 1.,3.3 Some dye plant effluents contain large amounts of components with retention times,closed to benzidine. In these cases, it has been found useful to reduce the electrode,potential in order to eliminate interferences and still detect benzidine. (See Section 12.7.),4. Saf……
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