The occurrence of anti-retroviral compounds used for HIV treatment in South African surface water

- An LC-MS/MS method for the detection of 12 antiretroviral drugs was developed.
- The compounds were detected in South African surface water for the first time.
- Targets occurred in the low to mid ng/L range.
- Nevirapine occurred ubiquitously across all the samples tested.
- Matrix effect was corrected for using a modified standard addition method.

The study and quantification of personal care products, such as pharmaceuticals, in surface water has become popular in recent years; yet very little description of these compounds' presence in South African surface water exists in the literature. Antiretrovirals (ARVs), used to treat human immunodeficiency virus (HIV) are rarely considered within this field. A new method for the simultaneous quantification of 12 antiretroviral compounds in surface water using the standard addition method is described. Water samples were concentrated by a generic automated solid phase extraction method and analysed by ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Substantial matrix effect was encountered in the samples with an average method detection limit of 90.4 ng/L. This is the first reported countrywide survey of South African surface water for the quantification of these compounds with average concentrations ranging between 26.5 and 430 ng/L.