title: Determination of benzodiazepines, related pharmaceuticals and metabolites in water by solid-phase extraction and liquid-chromatography-tandem mass spectrometry.
abstract: This work presents a method for the simultaneous determination of 23 benzodiazepines, metabolites and related pharmaceuticals (zolpidem, methylphenidate and ritalinic acid) by solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Different SPE cartridges were considered: hydrophilic modified reversed-phase (Oasis HLB) and their modified versions containing also a cationic-exchange group (Oasis MCX) or anionic-exchange (Oasis MAX) funcionalities. Stability of analytes and the impact of the final eluate volume on the matrix effects on LC-MS/MS were also considered. In the final method, 100-200 mL of sample are extracted with Oasis MCX (60 mg), eluted with 5 mL of methanol (1.25% NH3) and the eluate concentrated and analyzed by LC-MS/MS. Under these conditions, LOQs were established between 0.1 and 18 ng L(-1) for influent wastewater. The use of surrogated deuterated internal standards allows obtaining recoveries in the 84-122% range. Finally the method was applied to determinate the analytes in wastewater and surface water and 10 compounds were detected in the range of 0.5-170 ng L(-1), being the ritalinic acid (the main metabolite of methylphenidate) the analyte detected in the highest concentrations.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Sciences, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, R/Constantino Candeira SN, 15782 Santiago de Compostela, Spain.
authors.forename: Inés
authors.initials: I
authors.lastname: Racamonde
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Sciences, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, R/Constantino Candeira SN, 15782 Santiago de Compostela, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Rodil
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Sciences, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, R/Constantino Candeira SN, 15782 Santiago de Compostela, Spain. Electronic address: jb.quintana@usc.es.
authors.forename: José Benito
authors.initials: JB
authors.lastname: Quintana
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Sciences, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, R/Constantino Candeira SN, 15782 Santiago de Compostela, Spain.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Villaverde-de-Sáa
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Sciences, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, R/Constantino Candeira SN, 15782 Santiago de Compostela, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cela
mesh_terms: D001569:Benzodiazepines / Q000032:analysis; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D004364:Pharmaceutical Preparations / Q000032:analysis; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D001569:Benzodiazepines; D004364:Pharmaceutical Preparations; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Benzodiazepines; Liquid chromatography–mass spectrometry (LC–MS/MS); Methylphenidate; Ritalinic acid; Solid-phase extraction (SPE); Wastewater analysis