DETERMINATION OF COCAINE AND
BENZOYLECGONINE IN HUMAN PLASMA BY LC-MS/MS.
DANIELA-SAVETA POPA, LAURIAN VLASE, SORIN E.
LEUCUŢA, FELICIA LOGHIN
University of Medicine and Pharmacy „Iuliu Haţieganu”, Faculty of
Pharmacy, 13 Emil Isac, Cluj-Napoca - 400023, Romania
*corresponding author: dpopa@umfcluj.ro
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Abstract:

A high-throughput Liquid chromatography/ Mass spectrometry/ Mass spectrometry (LC/MS/MS) method for simultaneous quantification of cocaine (COC) and benzoylecgonine (BZE) in human plasma was elaborated. After the protein precipitation with methanol in the plasma samples, the analytes were separated on a Zorbax SB-C18 column under isocratic conditions using a 32:68 (v/v) mixture of methanol and 0.1% formic acid in water at 45ºC, with a flow rate of 1 mL/min. The detection was in multiple reaction monitoring (MRM) mode (m/z 290 → m/z 168 for BZE and m/z 304 → m/z 182 for COC, respectively). Calibration curves were generated over the range of 20-2000 ng/mL for both BZE and COC (r > 0.992). In the laboratories that are not equipped with a LC/MS/MS system, the LC analysis of COC and BZE requires a previous isolation step. Therefore, the elaborated LC/MS/MS method was applied for the study of optimum experimental conditions for the isolation of COC and BZE from human plasma. Several solvent mixtures and solid-phase extraction (SPE) cartridges were tested at different pH values. The best results for both analytes were obtained by SPE on Oasis HLB cartridges (mean recovery of 71 % for COC and 92.4 % for BZE, n = 3). Both the elaborated LC/MS/MS method and the best extraction conditions can successfully be applied in clinical and forensic toxicology for the rapid quantification of COC and BZE in human plasma

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