A Sensitive Ultra-High Performance Liquid Chromatography–Tandem Mass Spectrometry Method Based on Derivatization with 1-Nitro-2-Naphthaldehyde for Determination of Alkylhydrazines in Surface water

Background Alkylhydrazines are widely used in the industrial fields. An analysis of alkylhydrazines in surface water is need because these chemicals are likely to be discharged into wastewater and enter aquatic environments. Objective An ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method was developed to determine the levels of five alkylhydrazines (N,N-dimethylhydrazine, ethylhydrazine, 1-isopropylhydrazine, phenylhydrazine and 1-methyl-1-phenylhydrazine) in surface water. Methods This method is based on the derivatization of alkylhydrazines with 1-nitro-2-naphthaldehyde (NNA) in water. A derivatization reagent dosage of 0.5 mg of NNA, a pH of 2, and a reaction time of 30 min at 40 °C were determined to be the optimal conditions for UHPLC–MS/MS detection. The derivatives were injected into the LC system without additional extraction or purification steps. Results The proposed method was used under optimized conditions to detect alkylhydrazines in surface water, with the limit of quantification found to be 0.01–0.03 μg/L. The accuracy ranged from 91.0 to 106.0%, and the precision, expressed as the relative standard deviation, was less than 10%. Of the five alkylhydrazines, only N,N-dimethyl hydrazine was detected in the real samples at a concentration range of 0.010 to 0.041 μg/L. Conclusion The developed method can be used to confirm the presence of alkylhydrazine residues in surface water and represents an important tool for evaluating the fate of alkylhydrazines in surface water. Highlights This method to determine alkylhydrazine in surface water was developed simply and rapidly after derivatization reaction without an extraction or clean-up step in UHPLC-MS/MS.