Fully automated determination of N‐nitrosamines in environmental waters by headspace solid‐phase microextraction followed by GC–MS–MS

Abstract A fully automated method for determining nine Environmental Protection Agency N ‐nitrosamines in several types of environmental waters at ng/L levels is presented. The method is based on a headspace solid‐phase microextraction followed by GC–MS–MS using chemical ionization. Three different fibers (carboxen/PDMS, divinylbenzene/carboxen/PDMS, and PEG) were tested. Solid‐phase microextraction conditions were best when a divinylbenzene/carboxen/PDMS fiber was exposed for 60 min in the headspace of 10 mL water samples at pH 7 containing 360 g/L of NaCl, at 45°C. All compounds were analyzed by GC–MS–MS within 18 min. The method was validated using effluent from an urban wastewater treatment plant and the LODs ranged from 1 to 5 ng/L. The method was then applied to determine the N‐ nitrosamines in samples of different complexities, such as tap water and several influent and effluent wastewater samples from urban and industrial wastewater treatment plants and a potable water treatment plant. Although the analysis of influent industrial wastewater revealed high concentrations of some compounds ( N‐ nitrosomorpholine and N‐ nitrosodimethylamine at μg/L levels), in industrial effluents and other samples, the concentrations were substantially lower (ng/L levels). The new method is suitable for the simple and reliable determination of N ‐nitrosamines in highly complex water samples in a completely automated procedure.