Challenges in Detection of Antibiotics in Wastewater Matrix

Abstract

Currently, there is increasing awareness regarding the effect of antibiotics on various organisms in the ecosystem even though they may occur at relatively low concentration. Thus, their concentration needs to be quantified precisely in various matrices including ground water, surface water, and municipal wastewater. The use of liquid chromatography together with high-resolution mass spectrometry (HR-LC-MS/MS) has enhanced the reliability, accessibility, and accuracy with which antibiotics can be detected. In the present study, a HR-LC-MS/MS-based method was developed for four antibiotics (ciprofloxacin, norfloxacin, azithromycin, and sulfamethoxazole). Initially, various mobile phases and LC columns were evaluated. The effect of solution pH, drying time of cartridge, and solvent used in the concentration step on recovery of antibiotics during solid-phase extraction (SPE) was also evaluated. Subsequently, the recovery of antibiotics from influent and effluent wastewater samples, obtained from a wastewater treatment plant (WWTP) in India, was determined based on the matrix spike method. The results revealed that for these wastewater samples even the use of structurally similar, isotopically labelled (deuterated) standards could not adequately improve the recovery of target antibiotics.