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1 <br />1 <br />1 <br /> <br />1 <br />1 <br /> <br />1 <br />1 <br /> <br />1 <br />t <br /> <br />1 <br /> <br /> <br />LJ <br /> <br />1 <br />~~,~ <br />Western Atlas <br />International <br />.,.~...o... re..... <br />CORE LABORATORIES <br />r• r T r C I <br />ANALYTICAL CHEMISTRY DIVISION QUALITY ASSURANCE MANUAL <br />SDP N0. REVISION ND. EFFECTIVE 00.7E PAGE <br />HC-QAC-02 0 1 /06/92 68 of 104 <br />Instrument blanks are normally analyzed once per analytical batch of <br />samples. <br />Method 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 frorh 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 />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 />Reaoent Blanks <br />Reagent blanks are field samples containing all of the method reagents <br />except the color forming reagent. <br />Reagent blanks are used in certain colorimetric analyses to measure <br />potential colorimetric interferences derived from the sample matrix. <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 />Standards <br />