Abstract
Introduction. Unsymmetrical 1,1-dimethylhydrazine (UDMH), a highly toxic, carcinogenic substance of the 1st hazard class, is the main nitrogen-containing rocket fuel, but to date, in the Russian Federation and abroad, effective methods have not been developed for the quantitative determination of UDMH biomarkers in biological among workers in the rocket and space industry.
The aim of the study is to develop a new highly sensitive method for biological monitoring of UDMH using the most sensitive exposure biomarker – pyridoxal dimethylhydrazone in human urine using high-performance liquid chromatography with tandem mass spectrometric detection (HPLC-MS/MS).
Material and methods. measurement of mass concentrations of pyridoxal dimethylhydrazone in urine was performed by HPLC-MS/MS in reverse-phase HPLC mode with preliminary concentration by solid-phase extraction. To ensure the uniformity of measurements, a standard sample of pyridoxal dimethylhydrazone was synthesized domestically according to the previously described scheme [9].
Results. a method for measuring mass concentrations of pyridoxal dimethylhydrazone in urine in the range from 10 ng/ml to 1 μg/ml was developed, metrologically certified and entered into the Federal Register by HPLC-MS with solid-phase extraction.
Limitations of the study. ensuring the lower limit of quantification is achieved only through the use of a tandem mass selective detector. When using single quadrupole detectors, the limit increases by an order of magnitude.
Conclusion. it is advisable to carry out biological monitoring of the industrial effects of UDMH on the body of people in contact with it based on the quantitative determination of pyridoxal dimethylhydrazone in urine using the HPLC-MS method. The developed method makes it possible to measure the mass concentrations of pyridoxal dimethylhydrazone in urine in the range from 10 ng/ml to 1 μg/ml, which, according to estimates, will reveal the intake of 210 μg of UDMH per person weighing 70 kg per shift, corresponding to an 8-hour exposure to concentration 21 µg/m3 or 1/5 TWA (0.1 mg/m3).
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