1992-04-01_REVISION - M1988112 - Laserfiche WebLink

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~ ~1//~ CORE LABORATORIES ~ ' Western Atlas International ANALYTICAL CHEMISTRY DIVISION QUALITY ASSURANCE MANUAL ' SOP N0. FEVISION N0. EFFECTIVE GATE PAGE HC-QAC-02 0 1 /06/92 69 of 104 Standards are analyzed to measure the accuracy of laboratory analyses. Performance criteria for specific standard types are providQd in the applicable analytical method. General inorganic guidelines are providQd in Section 13.6. Calibration Standards Calibration standards are a series of formulated samples pf precisely known concentrations of the target analytes in the expected range. ' Calibration standards define the working range and linearity of the analytical ' method and establish the relationship of the instrument response to the target analyte concentration used to quantify field samples. ' The frequency, number of calibration points, and acceptance criteria for calibration standards varies considerably with the metlhod. Calibration requirements for each method and instrument are taught during analytical method training. External Reference Standard ' External reference standards are standards of known analyte concentration obtained from an external source (EPA, NIST, etc.) other than the source of the standards which are used for instrument calibration. External reference standards are used to verify the accuracy of the ' calibration standards. At a minimum, external reference standards are analyzed after each initial calibration. Frequency and acceptance criteria for external reference standard analyses vary considerably with the method. Hlequirements for each method and instrument are taught during analytical method training. ' Laboratorv Control Standard (LCS1 Laboratory control standards iLCS) are standards of known analyte concentration which are added to an interference-free matrix, such as, laboratory pure water or solvent. i