title: Development of a rapid column-switching LC-MS/MS method for the quantification of THCCOOH and THCCOOH-glucuronide in whole blood for assessing cannabis consumption frequency.
abstract: The concentration of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH) in whole blood is used as a parameter for assessing the consumption behavior of cannabis consumers. The blood level of THCCOOH-glucuronide might provide additional information about the frequency of cannabis use. To verify this assumption, a column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid and direct quantification of free and glucuronidated THCCOOH in human whole blood was newly developed. The method comprised protein precipitation, followed by injection of the processed sample onto a trapping column and subsequent gradient elution to an analytical column for separation and detection. The total LC run time was 4.5 min. Detection of the analytes was accomplished by electrospray ionization in positive ion mode and selected reaction monitoring using a triple-stage quadrupole mass spectrometer. The method was fully validated by evaluating the following parameters: linearity, lower limit of quantification, accuracy and imprecision, selectivity, extraction efficiency, matrix effect, carry-over, dilution integrity, analyte stability, and re-injection reproducibility. All acceptance criteria were analyzed and the predefined criteria met. Linearity ranged from 5.0 to 500 μg/L for both analytes. The method was successfully applied to whole blood samples from a large collective of cannabis consumers, demonstrating its applicability in the forensic field.
authors.affiliation: Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland. marianne.haedener@irm.unibe.ch.
authors.forename: Marianne
authors.initials: M
authors.lastname: Hädener
authors.affiliation: Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weinmann
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schürch
authors.affiliation: Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: König
mesh_terms: D002188:Cannabis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000097:blood; D004867:Equipment Design; D020719:Glucuronides / Q000097:blood*; D006801:Humans; D057230:Limit of Detection; D008385:Marijuana Smoking / Q000097:blood*; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000191:economics / Q000295:instrumentation / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000191:economics / Q000295:instrumentation* / Q000379:methods
chemical_list: D020719:Glucuronides; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol
keywords: Column-switching chromatography; DUI; LC-MS/MS; THCCOOH; THCCOOH-glucuronide; Whole blood