Determination of N-Nitrosamine Disinfection By-products in Drinking Water by Ultra-high Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry

In order to evaluate the potential risks posed by N-nitrosamines, a group of emerging disinfection by-products in drinking water, to the food and beverage industry, a method based on ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of nine N-nitrosamine disinfection by-products in drinking water. The samples were extracted by solid phase extraction. The chromatographic separation was accomplished on a RRHD-C₁₈ column with gradient elution using a mobile phase consisting of 10 mmol/L ammonium bicarbonate aqueous solution containing 0.2% formic acid and methanol. The detection was carried out using an atmospheric pressure chemical ionization (APCI) source in a multi-reaction monitoring (MRM) mode. Under optimized conditions, the calibration curves for nine N-nitrosamines were linear in a certain concentration range, with correlation coefficient greater than 0.996, and the detection limit of the developed method was 0.10–0.33 ng/L. The spiked recoveries of the method were 62.1%–118.2%, with relative standard deviation (RSD) of 2.2%–10.0%. The analysis process took 6 min. Compared with the existing methods, this method is very sensitive, fast and highly applicable, and can meet the requirements for the detection of N-nitrosamine disinfection by-products in drinking water for food and beverage production.