Laboratory of Environmental Analytical Chemistry, Core Facility Center "Arktika", Northern (Arctic) Federal University, Arkhangelsk 163002, Russia.
Federal Center for Integrated Arctic Research, Arkhangelsk 163000, Russia.
Molecules. 2022 Aug 7;27(15):5025. doi: 10.3390/molecules27155025.
When released to the environment, the rocket fuel unsymmetrical dimethylhydrazine (UDMH) undergoes oxidative transformations, resulting in the formation of an extremely large number of nitrogen-containing transformation products, including isomeric compounds which are difficult to discriminate by common chromatography techniques. In the present work, supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) was proposed for resolving the problem of fast separation and simultaneous quantification of 1-formyl-2,2-dimethylhydrazine (FADMH) as one of the major UDMH transformation products, and its isomers-1,1-dimethylurea (UDMU) and 1,2-dimethylurea (SDMU). 2-Ethylpyridine stationary phase provided baseline separation of analytes in 1.5 min without the distortion of the chromatographic peaks. Optimization of SFC separation and MS/MS detection conditions allowed for the development of rapid, sensitive, and "green" method for the simultaneous determination of FADMH, UDMU, and SDMU in environmental samples with LOQs of 1-10 µg L and linear range covering three orders of magnitude. The method was validated and successfully tested on the real extracts of peaty and sandy soils polluted with rocket fuel and UDMH oxidation products. It was shown that both UDMU and SDMU are formed in noticeable amounts during UDMH oxidation. Despite relatively low toxicity, UDMU can be considered one of the major UDMH transformation products and a potential marker of soil pollution with toxic rocket fuel.
当火箭燃料偏二甲肼（UDMH）释放到环境中时，会经历氧化转化，形成数量极多的含氮转化产物，包括难以通过常见的色谱技术区分的同分异构体化合物。在本工作中，提出了超临界流体色谱-串联质谱（SFC-MS/MS）用于解决快速分离和同时定量 1-甲酰基-2,2-二甲基肼（FADMH）作为 UDMH 主要转化产物之一及其异构体-1,1-二甲基脲（UDMU）和 1,2-二甲基脲（SDMU）的问题。2-乙基吡啶固定相在 1.5 分钟内提供了分析物的基线分离，而不会使色谱峰变形。对 SFC 分离和 MS/MS 检测条件的优化允许开发快速、灵敏和“绿色”的方法，用于同时测定环境样品中的 FADMH、UDMU 和 SDMU，LOQs 为 1-10 µg L，线性范围覆盖三个数量级。该方法已得到验证，并成功应用于受火箭燃料和 UDMH 氧化产物污染的泥炭和沙质土壤的实际提取物。结果表明，UDMH 氧化过程中会形成相当数量的 UDMU 和 SDMU。尽管 UDMU 的毒性相对较低，但它可以被认为是 UDMH 转化产物的主要产物之一，也是有毒火箭燃料污染土壤的潜在标志物。
