Development of solid phase extraction method for the LC-PDA detection of selected pharmaceuticals and their metabolites in surface water and sediment from the Isipingo River, KZN, South Africa

Multiple reports of pharmaceuticals and personal care products (PPCP's) have been established worldwide in different matrices of the environment. However, only a few of these investigations cover their metabolites in the environment. This study addresses the detection of ten selected pharmaceuticals including their dominant metabolites in surface water and sediments along the Isipingo River, KwaZulu-Natal, South Africa. A solid phase extraction method was developed for the simultaneous extraction of these targeted pharmaceuticals from different therapeutic groups in sediment and surface water samples. The extracted samples were analyzed using LC-PDA. Extraction times, solvent extraction, SPE sorbent type and extraction pH were optimized for both sediment and surface water samples to produce an overall analyte recovery of 59 -109 %. The limit of detection for surface water and sediments were 0.012–0.211 µg/L and 0.848–2.756 µg/kg, respectively. All target analytes and their dominant metabolites were detected in the range of 0.11–3.68 µg/L and 1.76–117.2 µg/kg for surface water and sediments, respectively. The trends show an increase in total PPCP levels along the flow of the river with the highest amounts detected at the outflow of the diversion works for sediments 358.89 µg/kg and surface water 11.07 ug/L.