Determination of polar 1H-benzotriazoles and benzothiazoles in water by solid-phase extraction and liquid chromatography LTQ FT Orbitrap mass spectrometry

“A sensitive, reliable and robust method for the trace determination of six polar 1H-benzotriazoles and four benzothiazoles in drinking and surface water was developed. These compounds were extracted from water by solid-phase extraction and analyzed by Liquid Chromatography–Electrospray Mass Spectrometry using a linear ion trap-Orbitrap hybrid instrument at high resolution of 30,000 FWHM in the full-scan acquisition mode. At least one product ion was simultaneously detected in the linear ion trap at low mass resolution and was used for confirmation of compound identity.

The compounds studied are soluble in water, resistant to biodegradation, only partially removed in wastewater treatment and they may pass the water treatment processes in the production of drinking water.

The analytes and four internal standards were preconcentrated by solid-phase extraction at low pH. Positive electrospray ionization resulted in protonated molecular ions for all the 1H-benzotriazoles and benzothiazoles.

The mass accuracy was between −5 ppm at m/z 120 and −0.1 ppm at m/z 182 and did not change for more than 2 ppm over a sample sequence of 8 days of analysis time. The optimized method allowed quantifying six benzotriazoles and four benzothiazoles in samples of drinking and surface water down to method detection limits of 0.01 μg/L. The recoveries ranged between 45 and 125% in ultrapure, drinking and surface water at a spiking level of 0.2 μg/L; the repeatability was between 2 and 13%. All analytes showed a linear response between 0.01 and 1.0 μg/L. No significant matrix effect was observed in drinking and surface water, except for the compounds 2-aminobenzothiazole (signal enhancement about 50%) and 2-hydroxybenzothiazole (signal suppression about 25%).

In Dutch drinking water samples, the compounds 1H-benzotriazole, 4- and 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 5-chloro-1H-benzothiazole and benzothiazole were detected. The concentration levels ranged from 0.01 to 0.2 μg/L. In surface waters, eight out of ten compounds tested were found to be present in concentration levels ranging between 0.1 and 1.0 μg/L. In addition, in effluents of two sewage treatment plants, eight out of ten compounds tested were present with maximum concentrations for 1H-benzotriazole of 8 μg/L and for methyl-1H-benzotriazole of 3 μg/L (summed concentration of two isomers).

This work demonstrates the excellent suitability of the LTQ FT Orbitrap mass spectrometer for this type of analysis.”

Copyright © 2009 Elsevier B.V. All rights reserved.

(Citaat: Leerdam, J.A. van, Hogenboom, A.C., et al., – Determination of polar 1H-benzotriazoles and benzothiazoles in water by solid-phase extraction and liquid chromatography LTQ FT Orbitrap mass spectrometry – International Journal of Mass Spectrometry Volume 282, Issue 3, 1 May 2009, Pages 99–107)