Radical indicator reaction for determination of 1,1-dimethylhydrazine

Talanta. 2019 Apr 1:195:599-603. doi: 10.1016/j.talanta.2018.11.095. Epub 2018 Nov 27.

Abstract

2,3,5-Triphenyl-2H-tetrazolium chloride (TPT) has been proposed as a redox indicator for determination of 1,1-dimethylhydrazine (DMH) which is used as a rocket propellant. It has been found that TPT is a sensitive chromogenic reagent due to its potentiometric and spectral characteristics. Products of the reaction between DMH and TPT have been characterized by mass spectrometry and EPR spectroscopy. In the EPR studies, C,N-diphenylnitrone (DPN) has been used as the radical trap and the obtained data indicate the radical nature of the reaction. The EPR spectrum of a mixture containing DPN and DMH has been recorded and calculated, whereas the spectrum of a three-component mixture containing DPN, TPT, and DMH is measured but it is complex for interpretation. A passive chemical dosimeter as a paper indicator strip with a polymer substrate impregnated with TPT has been manufactured and tested for continuous monitoring and determination of DMH in air in out-of-laboratory conditions at a concentration as low as 0.006 mg/m3 (warehouse operation area) and 0.5 mg/m3 (a warehouse box).

Keywords: 1,1-Dimethylhydrazine; Formazan; Indicator; Radical reactions; Tetrazolium.