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I <br />~ CORE LABORATORIES <br />~' ~ ~//% <br />' ~ Western Atlas <br />International <br />'' Tilt E <br />ANALYTICAL CHEMISTRY DIVISION QUALITY ASSURANCE MANUAL <br />' SOP N0. REVISION NG. EFFECTIVE GATE PAGE <br />HC-QAC-02 0 1 /06/92 77 of 104 <br />' • Matrix spikes are not required for the majority of gravimetric parameters. <br />' For gravimetric sulfates, matrix spikes must be analyzed once per batch or <br />at a frequency of 10% of the sample population, whichever is greater. <br />' Titrimetric Parameters <br />• Titrant normality must be verified initially by analyzing ~ known reference <br />material (if available) or stock solution. <br />' Class A burets must be used for titrimetric parameters. <br />• At a minimum, buret readings should be recorded to 0.01 mL. Where <br />' necessary, more accurate micro-burets should be used. <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 for at a frequency <br />' of 10% of the sample population, whichever is greater. <br />• Matrix spikes (where applicable) must be analyzed once~per batch or at a <br />'' frequency of 10% of the sample population, whichever is greater. <br />Colorimetric Parameters <br />' • At a minimum, spectrophotometers must be calibrated orahecked annually. <br />' • At a minimum, a 4-point calibration curve (blank and 3 Standards) should <br />be used for the majority or colorimetric parameters. <br />' • The correlation coefficient should be > 0.995 for the majority of <br />colorimetric parameters. <br />' • Initial calibration blanks must be analyzed prior to field sample analysis. <br />' • Continuing calibration blanks must be analyzed once per batch or at a <br />frequency of 10% of the sample population, whichever is greater. <br />1 <br />