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97/02/1999 13:03 972 <br /> - 091E <br /> GECANALYTICAL LA$ <br /> PAGE A_7 <br /> • <br /> EPA Methl9d 8082 (SW-846 Prop. Update III Re pAge 2 <br /> TITj-E Polychlorinated Biphenyls (pCBS)By Ca ill v 0, Jan 1995) <br /> Chromatogra by p ary Column Gas <br /> ("weathering")or degradation by treatment technologies. Such weathered <br /> multi-component mixtures may have significant differences in peak patterns <br /> than those of Aroclor standards. <br /> 1.3 Quantitation of PCBs as Aroclors is appropriate for many regulatory <br /> compliance determinations,but is particularly difficult when the Aroclors <br /> have been weathered by long exposure in the environment. <br /> method provides procedures for the determinationted Theref°re, this <br /> PCB congeners. The 19 PCB congeners listedabovehave been ested by <br /> this method. <br /> 1.4 The PCB congener approach potentially affords greater quantitative <br /> accuracy when PCBs are know to be present. As a result, this method may <br /> be used to determine Aroclors, some PCB congeners,or "total PCBs," <br /> depending on regulatory requirements and project needs. The congener <br /> method is of particular value in determining weathered Aroclors. However, <br /> analysts should use caution when using the congener method when <br /> regulatory requirements are based on Aroclor concentrations. <br /> 1.5 Compound identification based on single-column analysis should be <br /> confirmed on a second column, or should be supported by at least one other <br /> qualitative technique. This method describes analytical conditions for a <br /> second gas chromatographic column that can be used to confirm the <br /> measurements made with the primary column. GC/MS Method 8270 is also <br /> recommended as a confirmation technique when sensitivity permits (Sec. <br /> g.0). <br /> 1.6 This method also describes a dual-column option. The option allows a <br /> hardware configuration of two analytical columns joined to a single <br /> injection port. The option allows one injection to be used for dual-column <br /> analysis. Analysts are cautioned that the dual-column option may not be <br /> appropriate when the instrument is subject to mechanical stress, many <br /> samples are to be run in a short period,or when highly contaminated <br /> samples are analyzed. <br /> 17 The anaiyst must select columns,detectors and calibration procedures most <br /> appropnCe for he specific analytes of interest in a study. Matrix-specific <br /> performance dm must be established and the stability of the analytical <br /> system and instument calibration must be established for each analytical <br /> matrix i e g . bean solutions from sample extractions,diluted oil samples, <br /> etc.). Exa." :e ammatograms and GC conditions are provided as guidance. <br /> l 0.90 ug/L in water and <br /> 8 The�iDLs for►roclors vary in the range of 0.054 to <br /> S7 70 ug:'tig inoils.Estimated quantitation limits may be determined using <br /> the data in Tab 1. <br /> 19 Ttvs TMIhod restricted to use by,or under the supervision of, analysts <br /> experienced the use of gas chromatographs(GC)and skilled in the <br /> interpretatiof gas chromatograms.Each analyst must demonstrate the <br /> ability to gate acceptable results with this method. <br /> Genii tibUddng Corperadau19",Schenectady,NY 12304 <br />