AWWA WQTC69294

Hydrazine, as a potential chloramination disinfection byproduct with a 10^-6 cancer risk level of 10 ng/L, is in need of a high performance analytical method for precise and accurate monitoring at trace levels in drinking water. The conventional procedures for hydrazine determination are arduous with off-line extraction and concentration steps and also difficult to reach ppt levels of detection. This paper describes a new method for sensitive and selective determination of hydrazine in aqueous samples, involving derivatization with 2,3-Naphthalene dicarboxaldehyde (NDA) in sodium carbonate buffer, followed by separation and detection based on liquid chromatography coupled with electrospray tandem mass spectrometry (LC-ESI-MS/MS). In this method, a small volume (1 ml) of sample was derivatized, and an aliquot was directly injected in an on-line solid phase extraction (SPE-LC-MS/MS) system. A Lowest Concentration Minimum Reporting Limit (LCMRL) study was performed to validate the method along with precision and accuracy assessment from spiked sample recoveries. The LCMRL from 100µL injection was 5ng/L. The method detection limit (MDL) was 1ng/L, and even 0.1ng/L MDL can be achieved when the background contamination is in control. This method eliminates the off-line extraction and concentration step for hydrazine detection and also shows promise for sub-ppt level detection in aqueous samples. Hydrazine is stabilized by pre-adding the NDA to sample bottles to form the derivative in the field. Includes 9 references, tables, figures.