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

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.