Investigation on the compositions of unsymmetrical dimethylhydrazine treatment with different oxidants using solid-phase micro-extraction-gas chromatography–mass spectrometer

Abstract

The majority of unsymmetrical dimethylhydrazine (UDMH) treatments produce lots of toxic by-products, among which N -Nitrosodimethylamine (NDMA) is a strong carcinogen. The compositions of the by-products are important for evaluating the treatment efficiency and understanding the UDMH degradation mechanism to achieve UDMH mineralization. The intermediate and end products of UDMH treatment with different oxidants were investigated by using a simple and fast method, solid-phase micro-extraction (SPME) in combination with gas chromatography–mass spectrometry (GC-MS). The effects of several parameters (coating fibre, salt addition, pH, sampling time and desorption time) were studied to optimize analyte recovery. The best response can be attained by the 65 µm PDMS/DVB fibre at pH 7 during 10 min after desorption of 1 min in the GC inlet. The intermediate and final oxidative products of UDMH wastewater treatment with different oxidants (O 3 , Mn 2+ /O 3 , Fe 2+ /H 2 O 2 ) were investigated. The results showed that the UDMH treatment with O 3 could lead to high yields of NDMA. Metal catalytic ozonation could largely minimize the formation of NDMA. No NDMA was observed in the final decontaminated samples after treatment with Fe 2+ /H 2 O 2 . The NDMA formation and degradation mechanism were discussed based on the intermediates. This study is expected to provide useful information for controlling NDMA formation during UDMH wastewater treatment.

Insights into the Reaction Kinetics of Hydrazine-Based Fuels: A Comprehensive Review of Theoretical and Experimental Methods

“…Huang et al [96] explored the analysis of both intermediate and final products of UDMH (Unsymmetrical dimethylhydrazine) to comprehend the formation of harmful by-products and degradation mechanisms. The investigation involved exposing UDMH solutions to O 3 and examining the resulting degradation samples using SPME-GC/MS.…”

Rapid Simultaneous Quantification of 1-Formyl-2,2-Dimethylhydrazine and Dimethylurea Isomers in Environmental Samples by Supercritical Fluid Chromatography–Tandem Mass Spectrometry

“…When released to the environment, UDMH rapidly undergoes oxidative transformations via radical mechanism resulting in the formation of extremely large number (up to one thousand) of nitrogen-containing transformation products including toxic and carcinogenic compounds [ 3 , 4 ]. To date, several dozen UDMH transformation products have been reliably identified [ 5 , 6 , 7 ], the most abundant of them are N -nitrosodimethylamine (NDMA), formaldehyde dimethylhydrazone, 1,1,4,4-tetramethyltetrazene, N , N -dimethylformamide, dimethylaminoacetonitrile, 1-methyl-1H-1,2,4-triazole, and 1-formyl-2,2-dimethylhydrazine (formic acid N ′, N ′-dimethylhydrazide, FADMH) [ 8 , 9 , 10 , 11 , 12 , 13 ]. The latter compound has been identified as an UDMH transformation product relatively recently [ 9 ], although it is always found in significant amounts in soils and waters contaminated with rocket fuel [ 12 , 14 , 15 ].…”