Determination of 16 Kinds of N-Nitrosamines in Water by Gas Chromatography-Quadrapole-Orbitrap High Resolution Mass Spectrometry

A method for determination of 16 kinds of N-nitrosamines in drinking water was established using solid phase extraction-gas chromatography-orbitrap mass spectrometry. The water sample was extracted by solid phase extraction, concentrated by nitrogen blowing, separated by DB-35MS column, detected by high-resolution mass spectrometry , and quantified by internal standard method. The chromatographic separation conditions , such as ion source temp , carrier gas flow , injection mode and surge pressure of the method were optimized , and the optimal conditions were obtained including 280 degrees C of ion source temp , 2. 0 mL/min of carrier gas flow , and 200 kPa of splitless and surge pressure. Based on four-factor three-level orthogonal experiment, the solid phase extraction conditions were optimized as Chromabond HR-P and 10 mL of ethyl acetate. The results showed that the limits of detection ( LOD ) of the analytes were 0. 05-0. 50 ng/L, and the limits of quantitation ( LOQ ) were 0. 2-2. 0 ng/L , which were far lower than the literature value. The linear range was 0. 2 - 500 mu g/L with correlation coefficients ( R-2 ) of 0. 9943 - 0. 9997. The recoveries at four different spiking concentrations ranged from 72. 4% to 114.8% , and the relative standard deviations ( RSD , n =6) ranged from 0. 8% to 9. 5%. Finally, 12 actual water samples collected in Beijing were measured. Among them, five kinds of nitrosamines within 0. 9 ng/L to 20. 4 ng/L were detected. The method exhibited high sensitivity , selectivity and accuracy , and was suitable for the determination of trace nitrosamines in water.