scholarly journals Quantification of trace transformation products of rocket fuel unsymmetrical dimethylhydrazine in sand using vacuum-assisted headspace solid-phase microextraction

2022 ◽  
Author(s):  
Aray Zhakupbekova ◽  
Nassiba Baimatova ◽  
Elefteria Psillakis ◽  
Bulat Kenessov
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Transformation Products ◽  
Rocket Fuel ◽  
Headspace Solid Phase Microextraction ◽  
Unsymmetrical Dimethylhydrazine

scholarly journals Quantification of trace transformation products of rocket fuel unsymmetrical dimethylhydrazine in sand using vacuum-assisted headspace solid-phase microextraction

2021 ◽  
Author(s):  
Aray Zhakupbekova ◽  
Nassiba Baimatova ◽  
Elefteria Psillakis ◽  
Bulat Kenessov
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Transformation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Linear Calibration ◽  
Evacuation Time ◽  
Headspace Solid Phase Microextraction ◽  
Unsymmetrical Dimethylhydrazine ◽  
Target Analytes ◽  
Trace Concentrations

Abstract Quantification of unsymmetrical dimethylhydrazine (UDMH) transformation products (TPs) in solid samples is an important stage in monitoring of environmental pollution caused by heavy rockets launches. The new method for simultaneous quantification of UDMH TPs in sand samples using vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) followed by gas chromatography-mass spectrometry (GC-MS) is proposed. Compared to regular HSSPME, Vac-HSSPME yielded 1.3–4.8 times higher responses for NDMA, MTA and PAl. Increasing air-evacuation time from 20 to 120 s at 23 ºC resulted in decreased responses of analytes by 25–46%. Freezing of samples (-30 ºC) had negligible effect on responses of analytes at air-evacuation time 20 s. The best combination of responses of analytes and their RSDs was achieved after air-evacuation of a sample (m = 1.00 g) for 20 s at 23 ºC, incubation for 30 min and 30-min extraction at 40°C by Car/PDMS fiber. Vac-HSSPME provided linear calibration plots in studied ranges of concentrations with coefficients of determination ranging from 0.9912 to 0.9938. The limits of detection for spiked sand samples varied from 0.035 to 3.6 ng g− 1. Spike recoveries of target analytes from sand samples were 84–97% with RSDs 1–11%. The developed method was successfully tested in the experiment on studying losses of analytes from open vials with model sand spiked with UDMH TPs. The developed method can be recommended for analysis of trace concentrations of UDMH TPs when studying their transformation, migration and distribution in contaminated sand.

scholarly journals Quantification of transformation products of unsymmetrical dimethylhydrazine in aqueous extracts from soil based on vacuum-assisted headspace solid-phase microextraction

2018 ◽  
pp. 4-11 ◽  
Author(s):  
Dina Orazbayeva ◽  
Bulat Kenessov ◽  
Aray Zhakupbekova
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Transformation Products ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Fast Method ◽  
Aqueous Extracts ◽  
Headspace Solid Phase Microextraction ◽  
Unsymmetrical Dimethylhydrazine ◽  
Target Analytes

Quantification of transformation products of unsymmetrical dimethylhydrazine (UDMH) in soil requires tedious, time- and labor-consuming sample preparation. The simple and fast method for quantification of transformation products of UDMH in aqueous extracts from soil using vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) was optimized in this work. The method is based on extraction of analytes from soil with water followed by Vac-HSSPME of the obtained aqueous extracts, and gas chromatography-mass spectrometry analysis. The target transformation products were: pyrazine, 1-methyl-1H-pyrazole, N-nitrosodimethylamine, N,N-dimethylformamide, 1-methyl-1Н-1,2,4-triazole, 1-methyl-imidazole and 1H-pyrazole. The effect of a sample pH on responses of target analytes was studied. It was negligible, and no pH adjustment was recommended before a subsequent extraction. The water amount was optimized to provide the best combination of analytes responses and their precision. Extraction by adding 7.00 mL of water to 2.0 g of soil ensured linear dependence of responses of the analytes on their concentrations in soil. The optimized method provided detection limits of target analytes in soil in the range from 0.2 to 9 ng/g. The spike recoveries obtained for model samples were in the range 90-103%. The developed method can be recommended for application in laboratories conducting routine analyses of soil samples potentially contaminated by rocket fuel residuals.

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