Molecularly imprinted polymers as solid-phase and dispersive solid-phase extraction sorbents in the extraction of antiretroviral drugs in water: adsorption, selectivity and reusability studies

Abstract

The antiretroviral drugs (ARVDs) have been reported to be among the emerging water pollutants as a results attention is being paid on their analysis. This work therefore explored for the first time the multi-template MIP for the selective removal of selected ARVDs (abacavir, efavirenz and nevirapine) in wastewater, river water and tap water. The adsorption studies of a multi-template MIP were conducted by determining the effect of an increase in ARVDs concentration in solution and the effect of an increase in contact time between the sorbent and the ARVDs. High adsorption efficiencies were observed for abacavir, efavirenz and nevirapine analytes within 5 min and the maximum adsorption efficiency was observed at 60 min ranging from 94.76 to 96.93%. Adsorption kinetics showed that pseudo-second rate order was the best fitting model, while adsorption isotherms indicated that the Freundlich isotherm (R2 = 0.94–0.98) best described the adsorption mechanism of ARVDs onto the MIPs. These results indicated that the electrostatic attractions influenced the multilayer coverage and chemisorption process. Selectivity studies conducted in the presence of competitors gave the recoveries between 92 and 98% for the target analytes, while they were 63–79% for competitors indicating good selectivity and strong affinity of the polymer towards the target analytes. Reusability studies showed that the MIP can be reused for up to 8 cycles with recoveries above 92% for all target ARVDs. The application of the MIP-DSPE method to wastewater, river and tap water samples gave concentrations of 28.75–178.02, 1.95–13.15 and 2.17–6.27 µg L−1, respectively. These results indicate the potential unplanned consumption of ARVDs upon drinking contaminated water which could result to their resistance by the human body. Therefore, their continuous monitoring as well as investigation of their removal strategies is of paramount importance.