Simultaneous determination of drugs of abuse and their main metabolites using pressurized liquid extraction and liquid chromatography–tandem mass spectrometry

Abstract

An analytical method based on pressurized liquid extraction (PLE) and liquid chromatography–(electrospray)−tandem mass spectrometry was developed for the simultaneous determination of nicotine, four drugs of abuse (opiates and alkaloids) and four of their main metabolites in sewage sludge. The optimum PLE conditions were: cell volume 11mL, dichloromethane as extraction solvent, 5min preheating time, 100°C temperature, 1500psi pressure, 60% flush volume, 1 cycle, 15min static extraction time, 120s purge time and sample weight 1g. Absolute recoveries for all compounds were between 25% and 65%. Data acquisition was done by selective reaction monitoring and the two most abundant product ions were used for confirmation. Limits of detection were lower than 10μg/kg dry weight (d.w.) and limits of quantification were between 2.5 and 25μg/kg (d.w.).The highest concentrations found in sludge samples from two sewage treatment plants were for nicotine and cocaine in the range of 23–173μg/kg (d.w.) and 9–232μg/kg (d.w.) respectively.