EPA Method 613 2,3,7,8-Tetrachloro Dibenzo-p-Dioxin
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930181F14C27443495A01354CE6F7F66 |
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文件大小(MB)： |
0.1 |
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页数： |
20 |
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文件格式： |
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日期： |
2003-1-16 |
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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）：
APPENDIX A TO PART 136,METHODS FOR ORGANIC CHEMICAL ANALYSIS OF MUNICIPAL AND,INDUSTRIAL WASTEWATER,METHOD 613—2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN,1. Scope and Application,1.1 This method covers the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin,(2,3,7,8-TCDD). The following parameter may be determined by this method:,Parameter STORET No. CAS No.,2,3,7,8-TCDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34675 1746-01-6,1.2 This is a gas chromatographic/mass spectrometer (GC/MS) method applicable to the,determination of 2,3,7,8-TCDD in municipal and industrial discharges as provided,under 40 CFR Part 136.1. Method 625 may be used to screen samples for,2,3,7,8-TCDD. When the screening test is positive, the final qualitative confirmation,and quantification must be made using Method 613.,1.3 The method detection limit (MDL, defined in Section 14.1)1 for 2,3,7,8-TCDD is listed,in Table 1. The MDL for a specific wastewater may be different from that listed,depending upon the nature of interferences in the sample matrix.,1.4 Because of the extreme toxicity of this compound, the analyst must prevent exposure,to himself, of to others, by materials knows or believed to contain 2,3,7,8-TCDD.,Section 4 of this method contains guidelines and protocols that serve as minimum,safe-handling standards in a limited-access laboratory.,1.5 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.,1.6 This method is restricted to use by or under the supervision of analysts experienced,in the use of a gas chromatograph/mass spectrometer and in the interpretation of,mass spectra. 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 spiked with an internal standard,of labeled 2,3,7,8-TCDD and extracted with methylene chloride using a separatory,funnel. The methylene chloride extract is exchanged to hexane during concentration,to a volume of 1.0 mL or less. The extract is then analyzed by capillary column,GC/MS to separate and measure 2,3,7,8-TCDD.2,3,2.2 The method provides selected column chromatographic cleanup proceudres to aid in,the elimination of interferences that may be encountered.,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,backgrounds at the masses (m/z) monitored. 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.4 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, such as PCBs, may not be eliminated by the treatment. Solvent,rinses with acetone and pesticide quality hexane may be substituted for the,muffle furnace heating. Thorough rinsing with such solvents usually,eliminates PCB interference. 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 mininmize 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 coextracted 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. 2,3,7,8-TCDD is often associated with other interfering,chlorinated compounds which are at concentrations several magnitudes higher than,that of 2,3,7,8-TCDD. The cleanup producers in Section 11 can be used to overcome,many of these interferences, but unique samples may require additional cleanup,approaches1,5-7 to eliminate false positives and achieve the MDL listed in Table 1.,3.3 The primary column, SP-2330 or equivalent, resolves 2,3,7,8-TCDD from the other 2……
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