On‐Site Quantification of Transformation Products of Rocket Fuel Unsymmetrical Dimethylhydrazine in Air Using Solid‐Phase Microextraction

Despite the high importance of the monitoring of air pollution with transformation products (TPs) of rocket fuel unsymmetrical dimethylhydrazine (UDMH) in the regions of UDMH spills, there is a lack of simple, fast, and accurate methods for quantitation of UDMH TPs in air. This study was aimed at the development of the new method for on-site quantitation of UDMH TPs in air using solid-phase microextraction (SPME) and a portable gas chromatograph with nitrogen-phosphorus detector (GC-NPD). When using a known approach based on SPME from 20-mL vials filled with air, limits of detection (LODs) with a portable GC-NPD ranged from 4 to 10 µg/m³ that is about one order of magnitude higher than with a stationary GC-MS and can be insufficient for detecting UDMH TPs in real air samples. For achieving lower LODs, the sample volume has been increased to 250 mL. According to the modeling and experimental results, the optimal extraction time from 250-mL gas sampling bulbs was 15 min. Increase in the sample volume to 250 mL and extraction time to 15 min provided LODs 0.3-2 µg/m³. To enhance on-site measurements, preliminary screening using 24-h SPME from the liner (internal diameter 4.6 mm) exposed to the open air has been implemented. According to the modeling, such extraction parameters should provide 2.0-3.5 times greater amounts of analytes in the fiber coating. After screening, using this approach on the recent fall place of the first stage of the "Proton-M" carrier rocket, no analytes have been detected.