Gas chromatographic determination of cocaine and its metabolites in blood and urine from cocaine users in northwestern Spain

Abstract

A gas chromatographic method with fl ame ionization detection (GC/FID) was developed for the determination of cocaine and its metabolites in blood and urine samples from cocaine users in Northwestern Spain. After a solid-phase extraction with Bond Elut Certify cartridges and a derivatization with bis-trimethylsilyltrifluoroacetamide-trimethylchlorosilane (1%), calibration curves were constructed over 0.4-4 micro g ml(-1) for urine and 0.1-2 micro g ml(-1) for blood, using proadifen as the reference compound. The average extraction recoveries were 75% for urine and 78% for blood. The limits of detection and quantitation were 0.071 and 0.24 micro g ml(-1), respectively. Coefficients of variation were <10% and accuracy was within +/-12%. The average blood concentrations of cocaine, benzoylecgonine and ecgonine methyl ester in 42 living patients were 0.22, 1.43 and 0.16 micro g ml(-1), respectively. Urine samples were collected from individuals in the criminal justice system (70 cases), from drug abusers admitted to emergency rooms (36 cases) and from patients under detoxification treatment (36 cases). The second group exhibited the highest average concentrations (e.g. 0.97 micro g ml(-1) for cocaine, 5.23 micro g ml(-1) for benzoylecgonine and 0.39 micro g ml(-1) for ecgonine methyl ester). Sixty- five fatal intoxications due to cocaine alone or in combination with other drugs were studied, and average blood levels were found to be higher in the deaths related to cocaine alone (e.g. 0.40 micro g ml(-1) for cocaine, 2.38 micro g ml(-1) for benzoylecgonine and 0.38 micro g ml(-1) for ecgonine methyl ester).

Analysis of opiates, cocaine and metabolites in urine by high-performance liquid chromatography with diode array detection (HPLC-DAD)

“…The ratios obtained from the average urine concentrations showed that morphine was higher than MAM and codeine, BEG higher than cocaine and cocaethylene, and EDDP higher than methadone. Cocaine and BEG urine levels in our series were similar to those obtained by Peterson et al (1995) but higher than those published by Fernández et al (2004).…”

Tropane alkaloid analysis by chromatographic and electrophoretic techniques: An update

“…Different structural properties of cocaine and its metabolite not only render immunological detection difficult For GC-MS, polar metabolites often need derivatisation for exact quantitation. Silylation by BSTFA-TMCS like for atropine and scopolamine was applied to cocaine and the metabolites benzoylecgonine and ecgonine methyl ester [53]. Several silylation steps [46] or derivatisation with several reagents according to the chemical nature of the metabolites [54] were successful for detection of methyl ecgonidine and thirteen further cocaine metabolites in human blood and urine, however, they demanded tedious sample preparation.…”

Chemical Reagents and Derivatization Procedures in Drug Analysis

“…A BSTFA/TMCS mixture was also shown to be effective for derivatization of the opioid analgesic buprenorphine in association with benzodiazepines, (40) as well as cocaine and derivatives (41,42) before GC/MS. Seven diverse pharmaceuticals including caffeine, estradiol, ibuprofen, ketoprofen, musk ketone, naproxen, and triclosan were also more effectively derivatized using the BSTFA + TMCS combination as compared to TMSI.…”