Issue 4, 2009

Determination of bezafibrate, methotrexate, cyclophosphamide, orlistat and enalapril in waste and surface waters using on-line solid-phase extractionliquid chromatography coupled to polarity-switching electrospray tandem mass spectrometry

Abstract

We developed a rapid method for the monitoring of five selected pharmaceuticals in the influent and effluent of municipal wastewater treatment plants (WWTP) as well as in the effluent-receiving waters. To that end, we optimized and validated an analytical method based on on-line solid-phase extraction (on-line SPE) coupled with reversed-phase liquid chromatography-switching polarity electrospray ionization-tandem mass spectrometry (LC-ESI(±)-MS/MS). The target analytes have a variable hydrophobic character and belong to various therapeutic classes including the lipid regulator bezafibrate, the chemotherapy drugs methotrexate and cyclophosphamide, the lipase inhibitor orlistat and the angiotensin converting enzyme (ACE) inhibitor used in the treatment of hypertension, enalapril. The method combines positive and negative voltage switching modes, therefore all analytes can be determined using a single injection and without any reduction in sensitivity. In order to detect traces of these compounds, a preconcentration step before detection is performed by loading 1.00 mL of sample in an on-line SPE cartridge and eluting from the cartridge using a reversed-phase liquid chromatography gradient. Analysis of wastewater and surface water samples was greatly affected by co-eluting matrix compounds, to compensate for matrix effects quantitation was therefore performed using standard additions. Method intra-day precision was less than 6.5% and limits of detection in fortified matrix effluent samples ranged from 9 to 20 ng L−1. Four of the target pharmaceuticals were detected in the WWTP effluents, enalapril and bezafibrate being the most abundant compounds with concentrations of 35 and 239 ng L−1, respectively. Concentrations of these same compounds in surface water samples from sites downstream in the St. Lawrence River were 8 and 63 ng L−1, respectively, which was mainly due to dilution.

Graphical abstract: Determination of bezafibrate, methotrexate, cyclophosphamide, orlistat and enalapril in waste and surface waters using on-line solid-phase extraction liquid chromatography coupled to polarity-switching electrospray tandem mass spectrometry

Supplementary files

Article information

Article type
Paper
Submitted
07 Oct 2008
Accepted
11 Dec 2008
First published
21 Jan 2009

J. Environ. Monit., 2009,11, 830-838

Determination of bezafibrate, methotrexate, cyclophosphamide, orlistat and enalapril in waste and surface waters using on-line solid-phase extraction liquid chromatography coupled to polarity-switching electrospray tandem mass spectrometry

A. Garcia-Ac, P. A. Segura, C. Gagnon and S. Sauvé, J. Environ. Monit., 2009, 11, 830 DOI: 10.1039/B817570E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements