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1 <br /> <br /> <br />1 <br /> <br /> <br /> <br /> <br />1 <br />1 <br />1 <br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br />~,~(S~ • CORE LABORATORIES <br />Western Atlas <br />International <br />......,o.... ~.... <br />7171E <br />ANALYTICAL CHEMISTRY DIVISION QUALITY ASSURANCE MANUAL ~ <br />SOP N0. I REVISION NO <br />Hc-aac-o2 I o <br />EFFECTIVE GATE (PAGE <br />1106/92 I 76 of 1 <br />ReferencelLCS standards should be analyzed once per batch of <br />where available. <br />The analyzed recovery value must be within 90-110% of the known value. <br />When available, the recovery limits which are specified by the source of the <br />reference standard (EPA, NBS, etc.) should be used. <br />The following quality control guidelines apply to the majority of general <br />inorganic analyses which are performed on-site. <br />pH/Alkalinity/ACidity <br />• pH meters must be calibrated daily or at each use. <br />• Calibration verification using two buffer solutions at a pH of 4, 7, or 10 <br />must be performed prior to sample analysis. <br />• A method blank and reference standard Sif available) must be analyzed with <br />each sample batch, <br />• Laboratory duplicates must be analyzed once per batch or at a frequency <br />of 10% of the sample population, whichever is greater. <br />• Matrix spikes are not required. <br />Gravimetric Parameters <br />• An analytical balance with a resolution of 0.0001 grams should be used for <br />the majority of gravimetric parameters. Top-loading balances may be used <br />for certain parameters, such as percent moisture. <br />• Drying ovens used for gravimetric analysis must be monitored for correct <br />temperature adjustments on a daily basis (see section 9.2). <br />• A method blank and reference standard or stock standard (if available) must <br />be analyzed with each sample batch. <br />• Laboratory duplicates must be analyzed once per batch or at a frequency <br />of 10% of the sample population, whichever is greater: <br />