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

Alkylhydrazines are widely used in industrial fields. An analysis of alkylhydrazines in surface water is needed because these chemicals are likely to be discharged into wastewater and enter aquatic environments. An ultra-high performance liquid chromatography (UHPLC)-tandem mass spectrometry (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. 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 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. 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 0.010-0.041 μg/L. 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. A UHPLC-MSMS method was developed in order to dtermine the alkylhydrazine in surface water after derivatization without an extraction or cleanup step.