Abstract

The focus of this paper is to present techniques to overcome certain difficulties in quantitative analysis with a time- of-flight mass spectrometer (TOF-MS). The method is based on conventional solid-phase extraction, followed by reversed- phase ultra high performance liquid chromatography of the extract, and mass spectrometric analysis. The target compounds included atenolol, atrazine, caffeine, carbamazepine, diclofenac, estrone, ibuprofen, naproxen, simazine, sucralose, sulfamethox- azole, and triclosan. The matrix effects caused by high concentrations of organic compounds in wastewater are especially signif- icant in electrospray ionization mass spectroscopy. Internal-standard calibration with isotopically labeled standards corrects the results for many matrix effects, but some peculiarities were observed. The problems encountered in quantitation of carbamaze- pine and triclosan, due to nonlinear calibration were solved by changing the internal standard and using a narrower mass win- dow. With simazine, the use of a quadratic calibration curve was the best solution.