Determination of non-steroidal anti-inflammatory drug (NSAIDs) residues in water samples

The scope of this paper was to develop an analytical procedure to determine common pharmaceutical residues in wastewaters. Pharmacologically active substances were chosen according to their wide spread application in Slovenia and Central Europe and are members of analgesics, e.g., non-steroidal anti-inflammatory drugs: ibuprofen, naproxen, ketoprofen and diclofenac. Selected compounds were isolated from synthetic water using a novel SPE sorbent Strata™ X. Due to the non-volatile nature of these compounds they were first silylised prior to gas chromatographic-mass spectrometric detection. The developed procedure was tested with synthetic wastewaters and their extraction efficiency (>84%) and method limits of detection (2-6 ng L−1) were determined. Our procedure has been adopted and optimised for “real” water samples and applied to eleven drinking and ten river water samples from Slovenia. The results showed no traces of NSAIDs in all potable water samples and low-range contamination (ng L−1) of Slovene rivers. These results show that NSAIDs contamination of Slovene waters is comparable with published results of water contamination in Central Europe.