Determination of N-Nitrosamines by Gas Chromatography Coupled to Quadrupole–Time-of-Flight Mass Spectrometry in Water Samples

Benigno José Sieira,Rosario Rodil,Rafael Cela,José Benito Quintana,Inmaculada Carpinteiro

doi:10.3390/separations7010003

Benigno José Sieira, Rosario Rodil + Show 3 more

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https://doi.org/10.3390/separations7010003

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Journal: Separations	Publication Date: Jan 3, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: University of Santiago de Compostela

Abstract

An analytical method based on high-resolution quadrupole–time-of-flight (QToF) mass spectrometry has been developed as an alternative to the classical method, using a low-resolution ion trap (IT) analyzer to reduce interferences in N-nitrosamines determination. Extraction of the targeted compounds was performed by solid-phase extraction (SPE) following the United States Environmental Protection Agency (USEPA) -521 method. First, both electron impact (EI) and positive chemical ionization (PCI) using methane as ionization gas were compared, along with IT and QToF detection. Then, parameters such as limits of detection (LOD) and quantification (LOQ), linearity, and repeatability were assessed. The results showed that the QToF mass analyzer combined with PCI was the best system for the determination of the N-nitrosamines, with instrumental LOD and LOQ in the ranges of 0.2–4 and 0.6–11 ng mL−1, respectively, which translated into method LOD and LOQ in the ranges of 0.2–1.3 and 0.6–3.9 ng L−1, respectively. The analysis of real samples showed the presence of 6 of the N-nitrosamines in influent, effluent, and tap water. N-nitrosodimethylamine (NDMA) was quantified in all the analyzed samples at concentrations between 1 and 27 ng L−1. Moreover, four additional nitrosamines were found in tap and wastewater samples.

Highlights

The occurrence of N-nitrosamines in surface water, wastewater, and finished drinking water is a relevant issue of environmental and public health significance because many N-nitrosamines are probable human carcinogens, mutagens, and teratogens [1]
Nitrosamines have been found in surface and groundwater, in wastewater treatment plant influents and effluents, as well as in drinking water [2]
Three different capillary columns were tested using the temperature program described in Section 2.4 to obtain the best chromatographic separation

Summary

Introduction

The occurrence of N-nitrosamines in surface water, wastewater, and finished drinking water is a relevant issue of environmental and public health significance because many N-nitrosamines are probable human carcinogens, mutagens, and teratogens [1]. Potential sources of nitrosamines include postcombustion CO2 capture using amine-based scrubbing systems, tobacco smoke, and disinfection of drinking water. Nitrosamines have been found in surface and groundwater, in wastewater treatment plant influents and effluents, as well as in drinking water [2]. The occurrence of N-nitrosamines in drinking water or treated wastewater may be caused by the pollution of raw waters by nitrosamines or their formation during water treatment processes, such as chloramination or chlorination. They have been found in water as by-products of oxidized amines after chlorination treatment in wastewater treatment plants (WWTPs) [3].

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