Rapid quantification of free and glucuronidated THCCOOH in urine using coated well plates and LC-MS/MS analysis.
OBJECTIVE
Generally, urine drug testing for cannabis abuse involves measuring total concentrations of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) obtained by enzymatic and/or alkaline hydrolysis of THCCOOH-glucuronide. As hydrolysis can be inconsistent and incomplete, direct measurement of the two metabolites is preferable. Methodology & results: We developed a high-throughput LC-MS/MS method for simultaneous quantification of free and glucuronidated THCCOOH in urine using coated 96-well plates for analyte extraction and column-switching chromatography. Excellent separation of the two analytes was achieved within 2.5 min, with linear ranges from 5 to 2000 μg/l for THCCOOH and from 10 to 4000 μg/l for THCCOOH-glucuronide.


CONCLUSIONS
The method was successfully validated and applied to authentic urine samples from cannabis consumers, demonstrating its applicability for routine cannabinoid testing.
Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012 Bern, Switzerland.
Marianne
M
Hädener
Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012 Bern, Switzerland.
Wolfgang
W
Weinmann
Tecan Schweiz AG, Seestrasse 103, 8708 Männedorf, Switzerland.
Dave R
DR
van Staveren
Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012 Bern, Switzerland.
Stefan
S
König
D002188:Cannabis / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D013759:Dronabinol / Q000302:isolation & purification / Q000652:urine*; D020719:Glucuronides / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry
D020719:Glucuronides; D013759:Dronabinol
THCCOOH; THCCOOH-glucuronide; column-switching LC–MS/MS