Development and Validation of a Liquid Chromatography High-Resolution Mass Spectrometry (LC-HRMS) Bioanalytical Method for Quantifying Cannabinoids in Whole Blood: Application for Determining Recent Cannabis Use.
J AOAC Int. 2020 Jun 01;103(3):725-735
Authors: DeGregorio MW, Audino SA, Montoya E, Phong A, Kao CJ, Wurz GT
BACKGROUND: Cannabis legalization is expanding rapidly throughout the United States, but there is no reliable means of establishing recent use.
OBJECTIVE: To develop and validate a bioanalytical method for determination of Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol, 11-hydroxy-Δ9-THC, 11-nor-9-carboxy-Δ9-THC, and 8β,11-dihydroxy-Δ9-THC in whole blood microsamples by liquid chromatography high-resolution mass spectrometry (LC-HRMS).
METHODS: Cannabinoid extraction from whole blood was performed using a mixture of n-hexane/ethyl acetate (90:10, v/v). Chromatographic separation was performed with a C18 column using a binary mobile phase gradient of water and acetonitrile, each with 0.1% formic acid. Detection was performed by positive ion mode heated electrospray ionization with full scan MS on an Orbitrap mass spectrometer. A clinical study was performed in 30 subjects to identify recent cannabis use based on analysis of cannabinoids in blood samples up to 200 min post-smoking.
RESULTS: Acceptable linearity of all calibration curves was observed (r2>0.99) for all analytes over a 1-100 ng/mL concentration range, with acceptable accuracy. Limit of detection (LOD) was 0.5 ng/mL. Accuracy and precision met acceptance criteria for all analytes. Repeatability (CV) was <5% at low (3 ng/mL) and high (90 ng/mL) concentrations. In the clinical study, the ratios between 11-nor-9-carboxy-Δ9-THC and Δ9-THC fell immediately after smoking and returned to near baseline levels by 200 min post-smoking, which is consistent with recent use.
CONCLUSIONS AND HIGHLIGHTS: The developed LC-HRMS bioanalytical method is suitable for quantification of five key cannabinoids in whole capillary blood microsamples and can be used in conjunction with a test for determining recent cannabis use.
PMID: 33241370 [PubMed – in process]
Source: ncbi 2