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• <br />'~~~ <br /> CORE LABORAITORIES <br />Western Alias <br />International <br />tL~a~66 Cmy"Y <br /> i ~+ <br />February 2, 1994 <br /> FER ~ 19~ <br />Ms. Ann Maest <br />RCG Hagler/Bailly <br />P.O. Drawer 0 " ~~ 1. _ <br />~._:~. <br />Boulder. CO 80306 <br />Dear Ms. Maest: <br />As you requested during our phone conversation last week, this letter is written to larify our quality <br />wntrol reporting procedures. As I indicated, laboratory batch quality control data is ported on an "as <br />analyzed" basis (i.e. within calibration range at the instrument level). A quality control footer page <br />provided with all final reports includes a comment section which explains this reporting policy (see <br />attached). <br />Laboratory batch quality control data is reported in this manner for several reasons, All parameters <br />utilizing instrument calibrations include multiple quality control samples which are aqu us and could not <br />be reported with non-aqueous sample batches since the units reported would be differe t. Additionally, <br />the detection limit specified in the quality control report applies to all samples in thel QC batch. This <br />detection limit, if multiplied through due to dilution, digestion, or sample preparation d~rocedures, varies <br />considerably by sample and matrix type. For multiple parameters (all ICP and G1~AA metals), our <br />laboratory processes the raw lab data produced on the instrumentation directly into the Laboratory <br />Information Management System (LIMB) which produces the final report. This procedure requires that <br />quality control data be reported "as analyzed" at the instrument level. <br />The three cyanide samples in question (932003-4 T-CN, 932003 WAD CN, and X32003-6 T-CN) <br />required dilutions of 4, 4, and 2 times, respectively, to quantitate the cyanide w~thin the method <br />calibration range. The upper calibration standard for cyanide analysis is 0.50 mg/I.. These dilutions aze <br />reflected in the elevated detection limits reported for each sample. All other cyanide sa~ttples on this job <br />were low enough to be quantitated within the calibration range without dilution and are deported with the <br />normal 0.02 mg/L detection limit. <br />Please feel free to contact me at (303) 751-1780 if you need additional information or hive any questions <br />concerning this response. <br />Respectfully, <br />Linda L. Bankers <br />QA/QC Coordinator II <br />Analytical Chemistry Division <br />Attachment <br />cc: Ron Fuller -Laboratory Manager <br />10703 Ea51 Bethany Dnve Aurora. Colprado 800142696. (3031 751 a 780. Fax (303) 7514 784 <br />