Determination of 17 Amino Acids in Source Water by UPLC-MS/MS and Its Application

Amino acids are important part of nitrogen-containing organic matters in water and precursors of nitrogen-containing disinfection by-products. In order to understand the existence of dissolved amino acids in source water of China, a method for determining 17 amino acids in water by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established, and the occurrence of amino acids in different source waters was studied. The results showed that the linear range of the method was 1-200 nmol/L, the detection limit was 0.2-1.5 nmol/L, the coefficient of correlation (R²) was greater than 0.99, the precision of the method was from 0.11% to 4.66%, and the recovery ratio of the spiking samples were from 88.31% to 114.92%, which could meet the requirements of amino acids detection in water environment. This method provided a simple and reliable plan for the detection of amino acid concentration in surface water. The results of the actual sample showed that the total concentrations of dissolved amino acids in the Yangtze, Hanjiang, Dongjiang and Qiandao Lake waters were 1 296 nmol/L, 1 348 nmol/L, 885 nmol/L and 55 nmol/L, respectively.