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LFR Levine-Fricke <br /> heterogeneity or multiplicative interferences that diminish or enhance analytical signals. <br /> Sample results that do not meet precision objectives may still be considered usable for <br /> DQOs based upon professional judgment as to the cause and magnitude of the <br /> imprecision. All such decisions will be clearly justified in the data usability section of the <br /> validation report. <br /> A1.4.3 Sensitivity - Detection Limits <br /> The method detection limit (MDL) is the minimum concentration of an analyte that can <br /> be identified using a specific.method. The laboratory usually determines the MDL by <br /> calculating the standard deviation of the results of seven replicate spike sample <br /> analyses and multiplying by three, using reagent water as a sample. The MDL is an <br /> ideal detection limit when there is no background laboratory contamination and the <br /> sample to be analyzed is a clean sample free of matrix effects. MDLs, also known as <br /> the method quantitation limit, are determined using reagent water as the sample. <br /> MDLs are not field sample specific and do not vary with the sample preparation or <br /> dilutions required for each field sample analyzed. The MDL is the instrument detection <br /> limit (IDL) plus adjustments for typical sample preparation techniques. <br /> Sensitivity for this project will be evaluated against the specific project MDLs and <br /> internal standard recoveries. Quantitation limits may be affected by matrix interferences. <br /> If a dilution is required, the lowest dilution necessary to bring the compound within range <br /> should be performed in all cases. In cases where the specified detection limits (or project- <br /> specific reporting limits) are not achieved, the usability of the data will be evaluated by <br /> LFR. <br /> A1.4.4 Representativeness <br /> Representativeness expresses the degree to which the sample data accurately and <br /> precisely represent the media being sampled at a specific location at a specific time. One <br /> measure of representativeness is field duplicate precision. If field duplicate precision <br /> criteria are not met, LFR will determine usability of the associated results and qualify the <br /> data based upon best professional judgment. Poor field duplicate precision may be an <br /> indication of sample heterogeneity or poor sampling. <br /> A1.4.5 Comparability <br /> Comparability is the confidence with which one data set can be compared to other data. <br /> The objectives for this program are to produce data with the greatest degree of <br /> comparability possible. Comparability will be achieved using standard methods for <br /> sampling and analysis, reporting data in standard units, and using standard and <br /> comprehensive reporting formats. <br /> Page 6 Tracy-qWy-s=p-rpt-wrkpin(finap:JEE <br />