SPE-LC-PDA method development and application for the analysis of selected pharmaceuticals in river and wastewater samples from South Africa

The occurrence of pharmaceutical compounds in the environment has been a growing concern. However, there is little information on the concentration levels of pharmaceuticals in African countries. This indicates the need and the importance to develop sensitive methods that can detect these compounds at trace levels (ng/L-µg/L). This work reports on the development of solid phase extraction followed by liquid chromatography-photo diode array (SPE-LC-PDA) analysis. The method was then applied for the analysis of pharmaceutical compounds (ibuprofen, fenoprofen, naproxen, carbamazepine and diclofenac) in river and wastewater samples. The SPE recoveries obtained at 10 000 ng/L spike concentration ranged from 89-120% in distilled water, 79-110% in river water and 78-94% in wastewater. The LODs and LOQs ranged from 10.9-20.4 ng/L and 36.2-60.7 ng/L, respectively. Concentrations of the pharmaceuticals obtained in river water samples ranged from 60 to 32 900 ng/L; in wastewater they ranged from 70 to 66 900 ng/L. Higher concentrations of pharmaceuticals were detected in winter compared to the spring season.