Sample pre-treatment and analytical methodology for the simultaneous determination of pharmaceuticals and personal care products in sewage sludge.

This work describes the design, optimization and validation of an analytical method for the simultaneous determination of 14 pharmaceuticals and personal care products (PPCPs) in sewage sludge. A thorough optimization of the sample pre-treatment was carried out. As a result, microwave-assisted extraction (MAE) was combined with an in-situ clean-up stage and a filtration step. A combination of MilliQ® water/MeOH 95:5 (v/v) adjusted to pH 9 turned out to be the optimal solvent mixture for extraction. The instrumental part of the method presents a significant novelty based on a fully automated sample preparation for the analysis of PPCPs. It consisted of a direct immersion solid phase microextraction followed by on-fiber derivatization, online coupled to gas chromatography - mass spectrometry (DI-SPME-On-fiber derivatization - GC-MS). An isotope dilution approach was used for quantifying, which conferred high reliability to the method. This methodology was validated for 10 compounds with good analytical performance, limit of detection below 20 ng g-1 and absolute recovery in the range of 30-70% for most of the compounds. It supposes an ecological analytical alternative for many routine analysis laboratories around the world. The developed method was applied to different real samples generated in both a pilot-scale thermal hydrolysis treatment plant and an anaerobic digester operated in mesophilic conditions. Salicylic acid and naproxen were found at concentrations above 1000 ng g-1.

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".