Development of a modified acetonitrile-based extraction procedure followed by ultra-high performance liquid chromatography–tandem mass spectrometry for the analysis of psychiatric drugs in sediments

• Analysis of 8 psychiatric drugs and 3 metabolites in sediments.
• A modified QuEChERS extraction protocol was developed using basic acetonitrile.
• The proposed method is simple, rapid and sensitive.
• First time that antidepressants metabolites were detected in sediments

An analytical method based on a modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction procedure followed by ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was developed for the analysis of psychiatric drugs in sediments. An optimized approach was applied in sample preparation by using basic acetonitrile as extraction solvent. Extraction was followed by a clean-up using dispersive solid phase extraction (dSPE) to remove matrix interfering compounds. The analytical method was validated in terms of sensitivity, linearity, recovery, intra- and inter-day precisions and method detection and quantification limits. Under optimized conditions, limits of detection ranged from 0.01 ng g−1 to 2.08 ng g−1; and recoveries between 47 and 110% with relative standard deviation (RSD) below 5%. The developed methodology was applied to sediments of two Portuguese rivers (Douro and Lima rivers) and nine out of eleven psychiatric drugs were detected in sediments at concentrations up to 26.4 ng g−1 (dry weight). To the best of our knowledge, it was the first time that the human metabolites norfluoxetine and norsertraline were detected in river sediments at levels of few nanograms per gram.