Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS

Abstract

In this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE-ESI-MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal-to-noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQ's (signal-to-noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra-day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83-109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its metabolites was further confirmed by MS/MS experiments.

In-line solid-phase extraction–capillary electrophoresis coupled with mass spectrometry for determination of drugs of abuse in human urine

“…Different analytical methods based on liquid chromatography or gas chromatography, coupled to mass spectrometry for identification, have been developed for determination of drugs of abuse in environmental and biological samples [1][2][3][4]. Capillary electrophoresis (CE) has been proved to have great potential in the determination of drugs of abuse because of its excellent separation efficiency, low sample and solvent volumes, and high versatility in terms of separation modes [5][6][7]. These characteristics of CE make it suitable for the needs of forensic science laboratories [6,8,9].…”

“…Capillary electrophoresis coupled to mass spectrometry (CE-MS) has been increasingly used, because this hyphenation combines the high efficiency of CE with the universality, selectivity, and sensitivity of MS [7,9,24]. Since the development of electrospray ionization (ESI), in which ionized molecules can be efficiently transferred from a liquid to the gas phase, MS has become a valuable tool as detection system for CE, in particular for doping control and forensic screening [7,11].…”

“…Since the development of electrospray ionization (ESI), in which ionized molecules can be efficiently transferred from a liquid to the gas phase, MS has become a valuable tool as detection system for CE, in particular for doping control and forensic screening [7,11]. However, when MS is used as detection system some variables have to be taken into account to guarantee the good performance of the hyphenated system.…”

“…In this sense, the method is restricted to the use of specific types of BGE solutions of limited concentration [25]. Despite these limitations, some authors have successfully used CE-MS for biological samples [7][8][9]. For example, da Costa et al [7] proposed a method for determination of cocaine and its principal metabolites in urine by CE coupled to MS via electrospray ionization.…”

Investigation of in‐line solid‐phase extraction capillary electrophoresis for the analysis of drugs of abuse and their metabolites in water samples

“…As an example, Gottardo et al [11] described a new method for the determination of illicit drugs by capillary electrophoresis -electrospray ionization-time of flight-mass spectrometry in blood samples reaching limits of quantification ranging from 10 to Igor Botello Francesc Borrull Carme Aguilar Marta Calull 30 ng/mL. Also, da Costa et al [14] and Alnajjar et al [15] developed methodologies for the determination of illicit drugs and its metabolites in urine samples. The LODs achieved by da Costa et al were in the range between 100 and 250 ng/mL.…”