New MS method for the detection of cannabinoid use employs oral fluid samples

Written by Hannah Coaker, Future Science Group

LC/ESI–MS/MS analysis of oral fluid samples to check for recent cannabinoid use could address the significant drawbacks of current detection methods.

Scientists at the University of Freiburg (Freiburg, Germany), in collaboration with Biophor Diagnostics Inc. (Redwood City, CA, USA), have reported on the development, validation and application of an LC/ESI–MS/MS method for the quantification of 28 synthetic cannabinoids in neat oral fluid (OF) samples.

In general, serum and urine samples are used for the analysis of synthetic cannabinoids in biofluids, though their employment as analytical matrices for drug abstinence control entails some significant drawbacks: blood sampling is an inherently invasive sampling method, while urinary analysis of synthetic cannabinoids is limited by the lack of available reference standards of the respective major metabolites. In addition, the long detectability of synthetic cannabinoids in both matrices hinders the identification of recent synthetic cannabinoid use.

The research team, which was led by Volker Auwärter, (University Medical Center Freiburg [Freiburg, Germany]), prepared the OF samples by protein precipitation and achieved chromatographic separation by gradient elution. Subsequent detection was carried out on a QTrap 4000® instrument in positive ionization mode, where the limits of detection ranged from 0.02 to 0.40 ng/ml, and the lower limits of quantification ranged from 0.2 to 4.0 ng/ml. The method was applied to authentic samples collected during two preliminary studies in order to gain insights into the general detectability and detection windows of synthetic cannabinoids in the OF matrix.

The group observed that the synthetic cannabinoids were transferred from the bloodstream into the OF and vice versa at a very low rate, therefore indicating that positive OF samples are due to contamination of the oral cavity during smoking. The detection method was found to be capable of detecting drug contaminations of up to approximately 2 days, thus it was concluded by the team that neat OF is well suited for the detection of recent cannabinoid use.

Source: Kneisel S, Speck M, Moosmann B, Corneillie TM, Butlin NG, Auwärter V. LC/ESI-MS/MS method for quantification of 28 synthetic cannabinoids in neat oral fluid and its application to preliminary studies on their detection windows. Anal. Bioanal. Chem. 405 (14), 4691–4706 (2013).

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Hannah Coaker, Future Science Group

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LC/ESI–MS/MS analysis of oral fluid samples to check for recent cannabinoid use could address the significant drawbacks of current detection methods.