Analysis of 44 pharmaceuticals consumed by elderly using liquid chromatography coupled to tandem mass spectrometry

Elderly people represent about the 15% of the total world population and often include a polymedicated age group with an average consumption of 5-10 pills per day. The main pharmaceuticals consumed are antianalgesics, antidiabetics, anti-parkinson compounds, anti-convulsants, drugs to treat constipation and drugs to treat cancer. In this study, we have developed a multiresidue method for the analysis of 44 selected pharmaceuticals prioritized according to the foremost consumption by the elderly in effluents from senior residences. Given the complexity of these waters, method optimization included the selection of the extraction cartridge, pH and volume, and the optimization of the liquid chromatography-tandem mass spectrometry conditions to minimize matrix effects and obtain high yields. Good method performance was obtained, with recoveries between 27 and 116% and high sensitivity. The method was tested in a preliminar study to determine pharmaceuticals released in situ from the untreated effluents of the senior residences. High concentrations were detected, with levels between 0.20 and 2891 μg L^-1 attributed to the high consumption of drugs in the studied residences, which gather around 100 residents. The most detected pharmaceuticals were aspirin, macrogol, levofloxacin, cyclophosphamide, diclofenac, ibuprofen, paracetamol, carbamazepine, levetiracetam, pregabalin, quetiapine, chlormetiazole, trazodone, caffeine, 2,4-dichlorobenzyl alcohol and amylmetacresol. This study describes the analytical conditions to determine the outmost consumed pharmaceuticals in wastewaters released from senior residences.