Leverhulme Research Centre for Forensic Science LRCFS, University of Dundee, United Kingdom.
Forensic Services, Scottish Police Authority SPA, Edinburgh, United Kingdom.
Forensic Sci Int. 2021 May;322:110744. doi: 10.1016/j.forsciint.2021.110744. Epub 2021 Feb 22.
A method for the quantitative analysis of delta-9-tetrahydrocannabinol (THC, the main active ingredient of cannabis) in whole blood using solid phase extraction and LC/MS/MS has been developed. A bottom-up approach with method validation data was used to evaluate and estimate the measurement uncertainty (MU) of the analytical method. The sources of uncertainty were identified using a cause and effect diagram. The contribution of each uncertainty component was estimated and were combined to derive the overall uncertainty of the analytical method. The combined uncertainty was estimated to be 0.131 μg/L (<7%). At a 99.7% confidence level, the expanded uncertainty was 0.393 μg/L for a THC concentration of 2 μg/L in a whole blood sample. The calculations not only enable the laboratory to quantify the uncertainty associated with a quantitative result, but can also be used to identify the sources of uncertainty and determine if the analytical method can be improved. An open access Measurement Uncertainty Calculator (MUCalc) software has been developed using the method described in this paper.
已经开发出一种使用固相萃取和 LC/MS/MS 定量分析全血中 δ-9-四氢大麻酚 (THC，大麻的主要活性成分) 的方法。采用自下而上的方法和方法验证数据来评估和估计分析方法的测量不确定度 (MU)。使用因果图确定了不确定度的来源。估计了每个不确定度分量的贡献，并将其组合以得出分析方法的总不确定度。组合不确定度估计为 0.131μg/L（<7%）。在 99.7%置信水平下，全血样本中 THC 浓度为 2μg/L 时，扩展不确定度为 0.393μg/L。该计算不仅使实验室能够量化与定量结果相关的不确定度，还可以用于确定不确定度的来源，并确定分析方法是否可以改进。本文描述的方法已用于开发一个开放获取的测量不确定度计算器 (MUCalc) 软件。
