Estimation of Measurement Uncertainty in Quantitation of Benzoylecgonine (BZE) and 11-nor-Δ9-THC-9-carboxylic acid (THCA)
| Autor: | Darryl P. Arfsten, Erick Roman Perez, Neal C Goebel |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Quality Control
Health Toxicology and Mutagenesis Urinalysis Toxicology 01 natural sciences Gas Chromatography-Mass Spectrometry Analytical Chemistry 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Cocaine Limit of Detection Environmental Chemistry Humans 030216 legal & forensic medicine Dronabinol Reference standards Mathematics Detection limit Chemical Health and Safety Chromatography 010401 analytical chemistry Uncertainty Reproducibility of Results Reference Standards United States Department of Defense United States 0104 chemical sciences Substance Abuse Detection chemistry Calibration Benzoylecgonine Measurement uncertainty Analytical procedures Gas chromatography Cocaine urine |
| Zdroj: | Journal of analytical toxicology. 42(3) |
| ISSN: | 1945-2403 |
| Popis: | Calculating measurement uncertainty is a helpful exercise for identifying components or steps in a forensic analytical procedure that contribute to measurement variance. In this study, we used a bottom up approach to identify components in our procedures that contribute to measurement variance in our Department of Defense (DoD) Drug Demand Reduction Program (DDRP) Gas Chromatography Mass Spectroscopy (GCMS) analytical procedures for benzoylecgonine (BZE) and the THC metabolite, 11-nor-Δ9-THC-9-carboxylic acid (THCA) at 125% the DDRP concentration threshold (cutoff). Each assay was run 10 times over 30 days, each assay containing five calibrators and five samples (125%). Measurement uncertainty was estimated to be ±7.6 and ±0.6 ng/mL, for the BZE and THCA methods, respectively (α = 0.05). In both assays, method precision and the preparation of calibrator and samples were major contributors to measurement uncertainty. While this exercise will help with evaluating assay performance from a Quality Assurance perspective, these estimates should not be applied in interpreting DDRP test results. DDRP cut offs are already inherently conservative being above the Limit of Quantitation and were developed taking into consideration variability in assay performance across instruments and laboratories within the DDRP drug testing system. |
| Databáze: | OpenAIRE |
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