WORK PLANS - Laserfiche WebLink

Home Browse Search

9.1) Appendix 1 Student's t Values, Single-tail, 99% Confidence If the number of The Degrees of Freedom t Value To Use in aliquots used in the are defined as (n-1) MDL Calculation MDL study are: 7 6 3.143 8 7 2.998 9 8 2.896 10 9 2.821 11 10 2.764 16 15 2.602 21 20 2.528 26 25 2.485 26 25 2.485 31 30 2.457 36 35 2.438 41 40 2.423 51 50 2.403 61 60 2.390 71 70 2.381 81 80 2.374 91 90 2.368 101 100 2.364 121 120 2.358 00 00 2.326 9.2) Appendix 2 Additional Requirements for DoD/DOE Quality Systems Manual (QSM) Version 5.3 This procedure meets the general requirements of the DoD/DoE QSM Module 4, Section 1.5.2.1 that require a laboratory to establish a method detection limit (identified as DL in the QSM) using a published methodology from a recognized entity, in this case the EPA. However, the QSM has additional requirements that are listed here. 1. The QSM requires the laboratory to employ three reporting levels: DL, LOD, and LOQ. • QSM DL = MDL as given in this procedure. • QSM LOD = MDLV as given in this procedure. • QSM LOQ = LOQ as given in this procedure QSM Definitions: Detection Limit (DL): The smallest analyte concentration that can be demonstrated to be different from zero or a blank concentration with 99% confidence. At the DL, the false positive rate (Type I error) is 1%. The false negative rate is not controlled at this concentration. Detections in samples at concentrations between the DL and the LOQ are reported as estimated values, e.g., ]-flagged results. Limit of Detection (LOD): The smallest concentration of a substance that must be present in a sample in order to be detected at the DL with 99% confidence. At the LOD, the false negative rate (Type II error) is 1%. MDLV concentration establishes the LOD. For DoD/DOE projects, non-detect results are reported as <LOD" or"LOD U". Note that the QSM LOD is not equivalent to the TNI LOD. The LOD shall be at least 2 times but no greater than 4 times the DL. 2. Detection limit studies (MDLs and LODs) are required for all analytes, including surrogate compounds. 3. LOD verifications must be performed quarterly. The signal-to-noise ratio at the LOD must be at least three and the results must meet all method requirements of identification. For data systems that do not provide a measure of noise, the signal produced by the verification sample must produce a result that is at least 3 standard deviations greater than the mean Method Blank concentration. 4. If the LOD verification fails, then the laboratory must repeat the DL determination and LOD verification or perform and pass two consecutive LOD verifications at a higher spike concentration and set the LOD at the higher concentration. 5. The laboratory shall maintain documentation for all DL determinations and LOD verifications. r TI__ -. -._I 1 -- ___.._i 1__ .__.__._i_J L_._ _II _.__I..i_ ____i._.__ ..._1___ i _._._1.__LI_ i_ il__