Multi-residue determination of pharmaceuticals in sludge and sludge enriched soils using pressurized liquid extraction, solid phase extraction and liquid chromatography with tandem mass spectrometry

Abstract

An analytical method to determine a selection of 27 frequently prescribed and consumed pharmaceuticals in biosolid enriched soils and digested sludges is presented. Using a combination of pressurized liquid extraction, solid phase extraction and liquid chromatography with tandem mass spectrometry, it was possible to detect all analytes in each sample type at the low-sub ng g⁻¹ level. Solid phase extraction efficiencies were compared for 6 different sorbent types and it was found that Waters Oasis HLB cartridges offered enhanced selectivities with 20 analytes showing final method recoveries ≥60% in both soils and digested sludges. The method was validated for linearity, range, precision and limits of detection in both sample matrices. All analytes were then determined in sludge enriched soils as well as the precursor thermally dried sludge fertilizer produced from a primary wastewater treatment plant. Levels of the antibacterial agent triclosan were found to exceed 20 μg g⁻¹ in digested sludge and 5 μg g⁻¹ in thermally dried sludge cake. Significant traces of carbamazepine and warfarin were also detected in the above samples.