Combined microwave-assisted extraction and continuous solid-phase extraction prior to gas chromatography–mass spectrometry determination of pharmaceuticals, personal care products and hormones in soils, sediments and sludge

This paper reports a sensitive analytical method based on microwave-assisted extraction and continuous solid-phase extraction (SPE), followed by gas chromatography–mass spectrometry (GC−MS), for the simultaneous determination of residues of 18 pharmaceuticals (analgesics, antibacterials, anti-epileptics, β-blockers, lipid regulators and non-steroidal anti-inflammatories), one personal care product and 3 hormones in soils, sediments and sludge. The analytes are extracted with 3:2 methanol/water under the action of microwave energy and the resulting extract is passed through a SPE column to clean up the sample matrix and preconcentrate the analytes. Then, the analytes, trapped on Oasis-HLB sorbent, are eluted with ethyl acetate, silylated and determined by GC–MS. The proposed method provides a linear response over the concentration range 2.5–20 000 ng/kg with correlation coefficients higher than 0.994 in all cases. Also, it features low limits of detection (0.8–5.1 ng/kg), good precision (within- and between-day relative standard deviation less than 7%) and recoveries ranging from 91 to 101%. The method was successfully applied to agricultural soils, river and pond sediments, and sewage sludge. All samples contained some target analyte and sludge contained most —some at considerably high concentrations.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A new approach for the determination of 22 pharmaceuticals in soils is presented. ► Miniaturization of the sample treatment system using a MAE and a continuous SPE unit. ► Low limits of detection (between 0.8 and 5.1 ng/kg) were achieved. ► All samples analysed contained some target analyte (8.5–3100 ng/kg).