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Page 6 of 24 <br />SOP NUMBER 28.0 AnalOCal Data Validation <br />The individual methods include method-specific QC measures. The procedures used to evaluate <br />the results obtained for method specific quality control measures are described below. Section <br />4.1.6.1 describes method specific QC measure for inorganic methods and Section 4.1.6.2 <br />describes methods specific QC measures for organic methods. <br />4.1.6.1 Inorganic Method Specific QC Measures <br />For inorganic methods, method specific QC measures may include post-digestion spikes, serial <br />dilution tests, internal standard performance, and cation/anion balance calculation. Evaluation <br />procedures for each of these QC measures are described below. <br />4.1.6.1.1 Post Digestion Spike Recovery <br />The analyte recoveries obtained for post-digestion spike analyses will be compared to the <br />appropriate acceptance ranges per Section 4.1. Under some circumstances, laboratories will <br />quantify results by the method of standard additions to compensate for low post-digestion spike <br />recovery. In such a case, the low post-digestion spike recovery would not indicate poor <br />accuracy. However, if the result for the sample on which the post-digestion spike analysis was <br />performed was not obtained by the method of standard additions and the post-digestion spike <br />recovery is outside of the acceptance limits, qualify the result for the sample on which the post- <br />digestion spike was run based on the following guidance: <br />• If the recovery is > the upper acceptance limit, detectable results are qualified as estimated <br />("J"). No action needs to be taken for non-detects. <br />• If the recovery is < the lower acceptance limit, but >_ 30%, detectable and non-detectable <br />results are qualified as estimated ("J/UJ"). <br />• If the recovery is <30%, detectable results are qualified as estimated ("J") and non-detectable <br />results are qualified as unusable ("R"). <br />The data reviewer should use professional judgement in conjunction with other QC sample <br />results, such as matrix spike recoveries, to determine the need for qualification of results for <br />other samples (if any) associated with the post-digestion spike analysis. <br />A qualifier code of "PDS" will be assigned to all results qualified or rejected on the basis of <br />post-digestion recoveries and the assigned bias code will reflect the inferred bias direction. <br />4.1.6.1.2 Serial Dilution Test <br />ICP serial dilutions are run to help evaluate whether or not significant physical or chemical <br />interferences exist due to sample matrix. Serial dilution analyses are typically conducted at a <br />frequency of 1/20 samples (one analysis per metals data package). When analyte concentrations <br />are sufficiently high (the concentration in the original sample is minimally a factor of 50 above <br />the instrument detection limit [IDL] or method detection limit [MDL]), the results obtained for a <br />five fold-dilution of the original sample are compared to the original results by means of a <br />percent difference (%D). The %D is compared to a precision acceptance limit of =1:10%. If the <br />absolute value of the %D between the diluted and original result is >10%, all results for that <br />analyte in that sample batch are qualified as estimated ("J/UJ"). <br />Powertech <br />Rev 28-1 JAB <br />R Squared Inc <br />Attachment A <br />W <br />4/23/2007