Analytical methodologies for the determination of pharmaceuticals and personal care products (PPCPs) in sewage sludge: A critical review

Several analytical approaches have been developed for the determination of emerging pollutants (EPs), including pharmaceuticals and personal care products (PPCPs) in environmental matrices. This paper reviews the sample preparation and instrumental methods proposed in the last few years (2012-2018) to assess PPCPs in sewage sludge. Three main steps are examined: extraction, clean-up and analysis. Sample preparation is critical as target compounds are normally found at low concentrations in complex matrices. Most procedures include sewage sludge pretreatment mostly through ultrasound-assisted extraction (UAE) although other novel techniques such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) or MSPD (matrix solid-phase dispersion) have been also employed. In one report, no differences in extraction efficiency were detected among the most commonly used extraction techniques such as ultrasound, microwave and pressurized liquid. Clean-up usually involves a conventional method such as solid phase extraction (SPE). This step is needed to appreciably reduce matrix suppression, and is followed by an instrumental analysis using techniques of preference such as gas chromatography (GC) or liquid chromatography (LC), mostly coupled to mass spectrometry (MS). A fully automated on-line system that includes extraction, chromatographic separation, and mass spectrometry in one-stage is here presented as a novel way of determining PPCPs in sewage sludge. This review also discusses the advantages and limitations of the different techniques used. Miniaturizing analytical techniques and the use of novel solid and liquid phase materials are emerging as efficient options that fulfill the principles of so-called "green chemistry".