Journal of Chromatography & Separation Techniques
Open Access

Abstract

Quantification of Selected Antiretroviral Drugs in a Wastewater Treatment Works in South Africa Using GC-TOFMS

Schoeman C, Mashiane M, Dlamini M and Okonkwo OJ

Increasing amounts of Pharmaceutical Personal Care Products (PPCPs) have been detected in the water cycle in recent years. Of all the PPCPs, very little information regarding the determination of Antiretroviral Drugs (ARVDs) is available. The aim of this study was to monitor the concentrations of two ARVDs, nevirapine and efavirenz in influent and effluent points at a Wastewater Treatment Works in Gauteng, South Africa. Treated wastewater, before and after chlorination, was also examined to determine if the target ARVDs were removed by chlorination. The target ARVDs were extracted from wastewater using Solid Phase Extraction (SPE) and the extracts were subsequently analysed using Gas Chromatography-Time of Flight Mass Spectrometry (GC-TOFMS).The method (extraction plus instrumental) was validated to determine limits of detection and quantification; accuracy; precision and uncertainties (at 40 ng/L) and all were found to be well within requirements for part per trillion analyses. The robustness of the method was also determined by analysing 10 quality control replicates on three non-consecutive days and found to be fit for purpose. The concentrations of nevirapine and efavirenz in wastewater influent were found to be as high as 2100 and 17400 ng/L respectively. As much as 50% of the ARVDs were removed by the wastewater treatment plant and resulted in treated effluent concentrations of nevirapine and efavirenz as high as 350 and 7100 ng/L respectively. Chlorination was not found to affect the ARVDs significantly. The findings from two other investigations, one in Germany and the other from South Africa, that have investigated ARVDsin surface water and wastewater are compared with those of this study.