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~ `~11/~ <br />CORE LABORATORIES <br />Western Atlas <br />International <br />~~~7~_~ <br />ANALYTICAL CHEMISTRY DIVISION QUALITY ASSURANCE MANUAL <br />' SOP NO. AEVIS ION N0. EFFECTIVE GATE PAGE <br />HC-QAC-02 0 1!06/92 68 of 104. <br />1 <br /> Instrument blanks are normally analyzed once per analytical batch of <br /> samples. <br /> h <br /> Met <br />od Blanks <br /> Method blanks are laboratory pure water samples which contain all of the <br /> method reagents which have been introduced into the field samples. <br /> Method blanks are taken through all of the same sample preparation and <br /> analysis steps as field samples. <br /> Method blanks measure the combined contamination from laboratory pure <br />' water, method reagents, instrumentation, sample preparation, and analysis <br /> procedures. <br />' Measured analyte concentrations in method blanks should be less than the <br /> reported method detection limit. <br />r Method blanks are normally analyzed once per batch of samples or at a rate <br /> of 10% of the sample population, whichever is greater (i.e., 1-10 samples, <br />' 1 blank; 11-20 samples, 2 blanks, etc.l• <br /> Reagent Blanks <br /> <br /> Reagent blanks are field samples containing all of the rmethod reagents <br /> except the color forming reagent. <br /> <br /> Reagent blanks are used in certain colorimetric analyses to measure <br /> potential colorimetric interferences derived from the sample matrix. <br /> <br /> Instrument Carrvover Blank <br />' Instrument carryover blanks are laboratory pure water samples which are <br /> analyzed after ahigh-level sample. <br />' Carryover blanks measure the instrument contamination which may occur <br /> after analyzing highly concentrated samples. This type of blank is often <br /> used to decontaminate the instrument prior to continuing sample analysis. <br /> <br /> Standards <br /> <br />