Center of Physical Chemical Methods of Research and Analysis, Faculty of Chemistry and Chemical Technology, Al-Farabi Kazakh National University, 96a Tole bi Street, 050012 Almaty, Kazakhstan.
Core Facility Center 'Arktika', Northern (Arctic) Federal University, 163002 Arkhangelsk, Russia.
Talanta. 2018 Jul 1;184:332-337. doi: 10.1016/j.talanta.2018.02.047. Epub 2018 Feb 14.
Determination of transformation products (TPs) of rocket fuel unsymmetrical dimethylhydrazine (UDMH) in soil is highly important for environmental impact assessment of the launches of heavy space rockets from Kazakhstan, Russia, China and India. The method based on headspace solid-phase microextraction (HS SPME) and gas chromatography-mass spectrometry is advantageous over other known methods due to greater simplicity and cost efficiency. However, accurate quantification of these analytes using HS SPME is limited by the matrix effect. In this research, we proposed using internal standard and standard addition calibrations to achieve proper combination of accuracies of the quantification of key TPs of UDMH and cost efficiency. 1-Trideuteromethyl-1H-1,2,4-triazole (MTA-d3) was used as the internal standard. Internal standard calibration allowed controlling matrix effects during quantification of 1-methyl-1H-1,2,4-triazole (MTA), N,N-dimethylformamide (DMF), and N-nitrosodimethylamine (NDMA) in soils with humus content < 1%. Using SPME at 60 °C for 15 min by 65 µm Carboxen/polydimethylsiloxane fiber, recoveries of MTA, DMF and NDMA for sandy and loamy soil samples were 91-117, 85-123 and 64-132%, respectively. For improving the method accuracy and widening the range of analytes, standard addition and its combination with internal standard calibration were tested and compared on real soil samples. The combined calibration approach provided greatest accuracies for NDMA, DMF, N-methylformamide, formamide, 1H-pyrazole, 3-methyl-1H-pyrazole and 1H-pyrazole. For determination of 1-formyl-2,2-dimethylhydrazine, 3,5-dimethylpyrazole, 2-ethyl-1H-imidazole, 1H-imidazole, 1H-1,2,4-triazole, pyrazines and pyridines, standard addition calibration is more suitable. However, the proposed approach and collected data allow using both approaches simultaneously.
火箭燃料不对称二甲肼（UDMH）在土壤中的转化产物（TPs）的测定对于评估哈萨克斯坦、俄罗斯、中国和印度重型太空火箭发射对环境的影响非常重要。与其他已知方法相比，基于顶空固相微萃取（HS SPME）和气相色谱-质谱法的方法具有更大的简单性和成本效益。然而，HS SPME 对这些分析物的准确定量受到基质效应的限制。在这项研究中，我们提出使用内标和标准加入校准来实现 UDMH 关键 TPs 定量的准确性和成本效益的适当结合。1-三氘甲基-1H-1,2,4-三唑（MTA-d3）被用作内标。内标校准允许在含有<1%腐殖质的土壤中定量 1-甲基-1H-1,2,4-三唑（MTA）、N,N-二甲基甲酰胺（DMF）和 N-亚硝基二甲胺（NDMA）时控制基质效应。使用 65µm Carboxen/聚二甲基硅氧烷纤维在 60°C 下萃取 15 分钟，MTA、DMF 和 NDMA 在沙质和壤质土壤样品中的回收率分别为 91-117%、85-123%和 64-132%。为了提高方法的准确性并拓宽分析物的范围，对实际土壤样品进行了标准加入及其与内标校准的组合测试和比较。组合校准方法为 NDMA、DMF、N-甲基甲酰胺、甲酰胺、1H-吡唑、3-甲基-1H-吡唑和 1H-吡唑提供了最大的准确性。对于 1-甲酰基-2,2-二甲基肼、3,5-二甲基吡唑、2-乙基-1H-咪唑、1H-咪唑、1H-1,2,4-三唑、吡嗪和吡啶的测定，标准加入校准更为合适。然而，所提出的方法和收集的数据允许同时使用这两种方法。
