High sensitive multiresidue analysis of pharmaceuticals and antifungals in surface water using U-HPLC-Q-Exactive Orbitrap HRMS. Application to the Danube river basin on the Romanian territory.

The occurrence of 67 pharmaceutical and antifungal residues in the Danube river on the Romanian territory was studied by using solid-phase extraction (SPE) and LC-Q Exactive Orbitrap high resolution MS in both full scan (FS) MS and targeted MS/MS modes. A single-laboratory validation procedure was carried out for the determination of 67 compounds in FSMS mode evaluating selectivity, sensitivity, linearity, precision and accuracy. The method showed satisfactory analytical performance. The evaluation of the recovery concluded that 75% of the compounds show recoveries between 85 and 115% and 10% of the compounds show recoveries between 85% and 65%. The level of detection was lower than 5 ng l(-1) for 66% of the compounds, between 5 and 10 ng l(-1) for 22% and between 10 and 25 ng l(-1) for 14% of the compounds. The coefficients of determination R(2) were higher than 0.99 for 79% of the compounds, over a linearity range of 2.5-50 ng l(-1). Targeted MS/MS analysis, performed in addition to the full scan acquisition was used for confirmatory purpose. Twenty samples of Danube water and three of the main tributaries were collected in May, July, August and October 2014. Analysis of the selected water samples revealed the occurrence of 23 compounds such as diclofenac, carbamazepine, sulfamethoxazole, tylosin, indomethacin, ketoprofen, piroxicam, together with antifungals like thiabendazole, and carbendazim. Carbamazepine was detected in 17 samples, the maximum concentration being 40 ng l(-1). The highest concentration reached was 166 ng l(-1) for diclofenac.