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

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 11 mL, dichloromethane as extraction solvent, 5 min preheating time, 100 °C temperature, 1500 psi pressure, 60% flush volume, 1 cycle, 15 min static extraction time, 120 s purge time and sample weight 1 g. 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 10 μg/kg dry weight (d.w.) and limits of quantification were between 2.5 and 25 μg/kg (d.w.). ghest concentrations found in sludge samples from two sewage treatment plants were for nicotine and cocaine in the range of 23–173 μg/kg (d.w.) and 9–232 μg/kg (d.w.) respectively.