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C1 H n 0 I I k L' F 0 H P 1 17 4 7.7.2.3 If the range of the replicate analyses is greater than: the mean and if the concentration of the sample is greater than 3X LOD, the analyses are not acceptable. 7.7.2.4 If the range is within 20%, the mean and the standard deviation are reported. 7.7.2.5 If there is any reason to suspect the presence of an interferent (peak broadening, shift of retention time, shoulder formation, etc.), peak identification is verified using another analyzer (GC/MS), detector,or column. 7.7.2.6 When spiked samples are analyzed, the peak height and peak area ratios of the spiked and unspiked samples must be consistent. 7.7.3 Compound confirmation is a quality control procedure. 7.7.3.1 Ten percent of the analyses are confirmed by a different analytical system (different column or different detector, e.g. GUMS). 7.7.3.2 If the confirmatory and the routine analyses differ by more than 20%, none of the analyses are acceptable. 7.8 Analytical reports undergo quality control procedures. 7.8.1 Data storage: raw data transmitted from the integrator are stored unmodified in electronic storage. Data are archived according to date, site, analyses, and project for easy retrieval. These data are kept for 3 years in the laboratory electronic storage. 7.8.2 All data above the minimum detection limits are reported to the requesting agency in hard copy or electronic format. 7.8.3 All reports are reviewed by at least two qualified staff before they are released. 8 Critique and Comments 8.1 Lower limits of detection have been established using the prescribed instrument conditions and using a 100 mL sample with the freeze -out trap technique. 8.1.1 Table 8.1.1 lists the lower limits of detection for the I the compounds analyzed by this method. 8.2 Interferences are not usually a serious problem for light halogenated hydrocarbon analysis when the electron capture detector is used. 9