Determination of the products of the oxidative transformation of unsymmetrical dimethylhydrazine in soils by liquid chromatography/mass spectrometry

Procedures are developed on the basis of liquid chromatography/mass spectrometry for determining the transformation products of unsymmetrical dimethylhydrazine in soils: formic acid dimethylhydrazide (1-formyl-2,2-dimethylhydrazine, analytical range 0.01–20 mg/kg), 1-methyl-1,2,4-triazole (analytical range 0.05–100 mg/kg), 1,1-dimethylguanidine (analytical range 0.05–100 mg/kg), and dimethylamine (analytical range 0.25–250 mg/kg). The measurements were performed in the mode of chemical ionization under atmospheric pressure followed by the registration of positive ions corresponding to the protonated forms of the components to be determined. A version of ion chromatography was elaborated for separation. For sample pretreatment, the use of extraction with methanol (for 1-formyl-2,2-dimethylhydrazine) and ultrasonic extraction with a weakly alkaline buffer solution (for other substances) was proposed.