Determination of selected pharmaceutical residues in wastewater using an automated open bed solid phase microextraction system

The detection of trace levels of pharmaceuticals in environmental matrices requires an analyte pre-concentration procedure to obtain the required sensitivity for quantitative determination. This research aims to develop a simple automated analytical method based on C18 thin film solid phase microextraction (TF-SPME) for the simultaneous extraction of pharmaceutical compounds detected in surface waters. As a sample preparation method, solid phase microextraction, is a rapid, environmentally friendly, and a sensitive analytical technique which isolates and pre-concentrates trace organic pollutants from environmental water samples in a single step. High throughput analysis was achieved with the use of a robotic auto sampler which enabled parallel analyte extraction in a 96-well plate format. Application of the method was demonstrated using wastewater from pilot-scale municipal treatment plants and environmental water samples from wastewater-dominated reaches of the Grand River (adjacent Waterloo, ON) which were analysed using a liquid chromatography–mass spectrometry (LC–ESI–MS/MS) technique. The proposed method successfully determined concentrations of carbamazepine, fluoxetine, sertraline, and paroxetine in treated effluent at concentrations ranging from 240 to 3820 ng/L with a method detection limit of 2–13 ng/L with a relative standard deviation of less than 16%. Matrix effect was not observed with this method; therefore internal standards are not necessary for quantification of target compounds. The results suggest that this method is capable of detecting and quantifying many compounds present in both wastewater and wastewater-influenced surface water from multiple municipal sources. In this study, automated TF-SPME system is demonstrated as a simple and fast alternative method for high throughput analysis of pharmaceutical contaminants in environmental matrices.

► A simple and automated solid phase microextraction method is developed.
► Pharmaceutical residues in waste water samples were detected and determined.
► High throughput analysis in waste water is achieved using 96-well format.
► Improved sensitivity and fast equilibration is achieved with the new method.
► Application of the method to real samples is demonstrated.