Analysis of Cannabinoids and Metabolites in Dried Urine Spots (DUS).

Matteo Moretti,Carlo Previderé,Pierangela Grignani,Maria Cobo-Golpe,Luca Morini,Francesca Freni,Claudia Carelli,Claudia Vignali

doi:10.3390/molecules26175334

Matteo Moretti, Carlo Previderé + Show 6 more

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https://doi.org/10.3390/molecules26175334

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Abstract

Dried urine spots (DUS) represent a potential alternative sample storage for forensic toxicological analysis. The aim of the current study was to develop and validate a liquid chromatographic tandem mass spectrometric procedure for the detection and quantitative determination of cannabinoids and metabolites in DUS. A two-step extraction was performed on DUS and urine samples. An LC-MS/MS system was operated in multiple reaction monitoring and positive polarization mode. The method was checked for sensitivity, specificity, linearity, accuracy, precision, recovery, matrix effects and carryover. The method was applied to 70 urine samples collected from healthy volunteers and drug addicts undergoing withdrawal treatment. The method was successfully developed for DUS. LODs lower than 2.0 ng/mL were obtained for all the monitored substances. All the validation parameters fulfilled the acceptance criteria either for DUS or urine. Among the real samples, 45 cases provided positive results for at least one compound. A good quali-quantitative agreement was obtained between DUS and urine. A good stability of THC, THCCOOH and THCCOOH-gluc was observed after a 24 h storage, in contrast to previously published results. DUS seems to provide a good alternative storage condition for urine that should be checked for the presence of cannabinoids and metabolites.

Highlights

Dried matrix spots (DMS) are increasingly being used for numerous applications in the field of clinical and forensic toxicology.This technique consists of taking and depositing a small amount of a biological fluid onto a filter card and letting it dry
The analytical procedure was fully validated for THC, CBG, CBD and three metabolites of THC, namely, 11-OH-THC, THCCOOH and THCCOOH-gluc
Methanol was chosen as the extraction solvent for several reasons. It is a relatively low-cost solvent; it is less toxic than others; and the laboratory is very experienced in extraction procedures, including the extraction of phytocannabinoids from biological matrices based on methanol

Summary

Introduction

Dried matrix spots (DMS) are increasingly being used for numerous applications in the field of clinical and forensic toxicology.This technique consists of taking and depositing a small amount of a biological fluid (blood, urine, sweat, etc.) onto a filter card and letting it dry. Since the 1950’s, several methods have been developed and validated for dried blood spots [1,2,3,4,5,6]. Among DMS, dried urine spots (DUS) have successfully been used for several analytical purposes. In 1959, DUS was used to detect specific proteins in urine, in order to diagnose diseases such as phenylketonuria [7]. The use of DUS was adapted in the following years to search for other proteins and metabolites [8,9,10,11,12]

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