A μ-SPE procedure for the determination of cannabinoids and their metabolites in urine by LC-MS/MS.
In this paper the development and validation of a method for the analysis of THC-COOH, THC, THC-OH, CBD and CBN in their total form in urine by LC-MS/MS is presented. Tandem hydrolysis, i.e. enzymatic and basic, has been found optimal for the simultaneous analysis of the selected analytes in urine: basic hydrolysis is more effective for the cleavage of THC-COOH glucuronide while enzymatic hydrolysis allows the cleavage of the conjugated cannabinoids possessing ether bonds (THC, THC-OH, CBD). The whole procedure requires a 2h enzymatic hydrolysis using only 90μL of urine by μ-SPE extraction technique with C18 tips. Clear advantages in terms of time and of enzyme reduction are obtained and the cost of the analysis can be dramatically reduced. Satisfactory recovery values and matrix effect are obtained, and the chromatographic run, performed with a fused-core column, allowed the complete analyte separation in only 3min (total run 5.8min) with a common HPLC system. Furthermore the whole procedure has been validated according to SWGTOX guidelines: LOQs are between 6 and 10ppb, quite lower than the requested cut-off for urine testing; intermediate reproducibility of the selected analytes is below 10% and accuracy is between 85% and 113%, except for CBD, included only for semi-quantitative determination.
Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy.
Camilla
C
Montesano
Department of Food Sciences, University of Teramo, 64100 Teramo, Italy. Electronic address: msergi@unite.it.
Manuel
M
Sergi
Institute of Legal Medicine, Catholic University of Sacred Heart, 00168 Rome, Italy.
Sara
S
Odoardi
Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy.
Maria Chiara
MC
Simeoni
Department of Food Sciences, University of Teramo, 64100 Teramo, Italy.
Dario
D
Compagnone
Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy.
Roberta
R
Curini
D002186:Cannabinoids / Q000737:chemistry* / Q000378:metabolism / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006868:Hydrolysis; D053719:Tandem Mass Spectrometry / Q000379:methods; D014556:Urine / Q000737:chemistry*
D002186:Cannabinoids
Cannabinoids; LC–MS/MS; Micro-SPE; Tandem hydrolysis; Urine