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On-line SPE LC-MS/MS for the quantification of Δ9-tetrahydrocannabinol (THC) and its two major metabolites in human peripheral blood by liquid chromatography tandem mass spectrometry

König, Stefan ; Aebi, Beat ; Lanz, Stephan ; Gasser, Martina ; Weinmann, Wolfgang

In: Analytical and Bioanalytical Chemistry, 2011, vol. 400, no. 1, p. 9-16

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    Title
    • On-line SPE LC-MS/MS for the quantification of Δ9-tetrahydrocannabinol (THC) and its two major metabolites in human peripheral blood by liquid chromatography tandem mass spectrometry
    Author
    • König, Stefan. Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland
    • Aebi, Beat. Chemistry Department, Spiez Laboratory, Federal Office for Civil Protection, 3700, Spiez, Switzerland
    • Lanz, Stephan. Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland
    • Gasser, Martina. Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland
    • Weinmann, Wolfgang. Institute of Forensic Medicine, University of Bern, Bühlstrasse 20, 3012, Bern, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:319599
    Summary
    A universal and robust analytical method for the determination of Δ9-tetrahydrocannabinol (THC) and two of its metabolites Δ9-(11-OH)-tetrahydrocannabinol (11-OH-THC) and 11-nor-Δ9-carboxy-tetrahydrocannabinol (THC-COOH) in human whole blood was developed and validated for use in forensic toxicology. Protein precipitation, integrated solid phase extraction and on-line enrichment followed by high-performance liquid chromatography separation and detection with a triple quadrupole mass spectrometer were combined. The linear ranges used for the three cannabinoids were from 0.5 to 20ng/mL for THC and 11-OH-THC and from 2.5 to 100ng/mL for THC-COOH, therefore covering the requirements for forensic use. Correlation coefficients of 0.9980 or better were achieved for all three analytes. No relevant hydrolysis was observed for THC-COOH glucuronide with this procedure — in contrast to our previous GC-MS procedure, which obviously lead to an artificial increase of the THC-COOH concentration due to the hydrolysis of the glucuronide-conjugate occurring at high pH during the phase-transfer catalyzed methylation step