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EASE <br /> i I <br /> Trecar Renaar•th Garpar"J" <br /> I <br /> 1 <br /> ANALYTICAL PROCEDURES <br /> One Varian 3300 gas chromatograph, equipped with a flame ionization detector <br /> (FID), was used for the sample analyses. The FID was used for the analvsis of benzene, <br /> toluene, ethvlbeazene, xylenes and total hydrocarbons. Separation of the FID compounds <br /> was achieved on a 3' by 1/S" <br /> OD packed column with OV-141 as the stationary phase and <br /> nitrogen as a carrier gas. <br /> Volatiles detected in soil gas and groundwater were identiried by chromatographic <br /> f retention time. Quantification of compounds was achieved by comparison of the detector <br /> t:. response of the sample with the response measured for calibration standards (,.sternal <br /> standardization). Instrument calibration checks were run periodically throughout the day <br /> `. as were system blanks to check for contamination in the soil pas sampling equipinextt. Air <br /> samples were also routinely analyzed to check for back,ound levels in the atmosphere. <br /> Detection limits for the compounds of interest are a function of the injection volume <br /> as well as the detector sensitivity for individual c,--npounds. Thus,the detection limit varies <br /> with the sample size. Generally, the larger the injection size the greater the sensitivity. <br /> However, peaks for compounds of interest must be kept within the linear range of the <br /> ('# analytical equipment. If any compound has a high concentration, it is necessary to use <br /> small injections,and in some cases to dilute the sample to keep it within linear range. This <br /> f ' <br /> may cause decreased detection litrits for other compounds in the analyses. <br /> tr <br /> 1 , • <br /> The detector:limits range down to approximately 0.05 ug/L for compounds screened <br /> ° on the FID depending on the conditions of the measurement,in particular,the sample size. <br /> t^� <br /> If any component being analyzed is not detected, the detection limit for that compound in <br /> that analysis is given as a "less than' value (!II.g. <0.05 ug/L). Detection limits obtained <br /> ILA from GC analyses are calculated from the current response factor,the sample size,and the <br /> estimated minimum peak size (area) that would have been visible under the conditions of <br /> the measurement. <br /> -- <br /> 4 <br /> ins <br />