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CORE LABORATORIES <br />'®~~~ <br />Western Atlas <br />International <br />..~,r,..~ cam.. <br />' TITLE <br />ANALYTICAL CHEMISTRY DIVISION QUALITY ASSURANCE MANUAL <br />' SOP NO. REVISION N0. EFFECTIVE DATE PAGE <br />HC-QAC-02 0 1 /06/92 76 of 104 <br />' <br /> Reference/LCS standards should be analyzed once per batch of samples, <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(Alkaf+nitv(Acidity <br /> • pH meters must be calibrated daily or at each use. <br />' <br /> • Calibration verification using two buffer solutions at a pH of 4, 7, or 10 <br /> must be performed prior to sample analysis. <br /> <br /> • A method blank and reference standard (if available) must be analyzed with <br /> each sample batch. <br /> <br /> • Laboratory duplicates must be analyzed once per batch or at a frequency <br /> of 10% of the sample population, whichever is greater. <br />' <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 balancgs 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 9.21. <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 />I of 10°!° of the sample population, whichever is greater. <br />I <br />