Analysis of 60 pharmaceuticals and personal care products in sewage sludge by ultra-high performance liquid chromatography and tandem mass spectroscopy

This paper presents a comparison of three different analytical proposals for the determination of 60 pharmaceuticals and personal care products (PPCPs) in solid urban sewage sludge. Two fast sample pretreatments, i.e., online solid-phase-extraction (online SPE) and direct injection (DI), were tested against the conventional offline solid phase extraction (offline SPE). In all cases, subsequently, extracts underwent ultra-high-performance-liquid chromatography coupled to tandem-mass-spectrometry (UHPLC-MS/MS), simultaneously operating in both positive and negative electrospray ionization (ESI) mode. In addition, as solid matrices, clean-up steps were necessarily preceded by ultra-sound-assisted extraction (UAE) in all cases. Matrix-matched quantification was combined with internal standard providing high reliability to all three approaches. Best performance was observed for the fully automatized and non-pretreated DI method, showing limits of detection below 30 ng g−1 for many of the target compounds, and recoveries between 80 and 120%. Finally, the best working method was validated and applied to the analysis of PPCPs in different dewatered digested sludge samples from the wastewater treatment plant (WWTP) in Valladolid (Spain). Acetaminophen was found at concentrations above 1,000 ng g−1.