[Gas chromatographic determination of N,N-asymmetric dimethylhydrazine in different environmental objects].

The paper describes different guidelines used to develop a procedure for gas chromatographic determination of N,N-asymmetric dimethylhydrazine (NDMH) in various environmental objects in the area of a missile-dismantling base. The authors showed that the use of a capillary column with a 5-microm liquid phase layer on a Kristall-5000 chromatograph with a nitrogenous phosphoric detector (Russia) allowed development of a unified gas chromatographic procedure for determining NDMH in air, water, soil, biological material (urine), and plant cover (moss, couch-grass). The procedures differ in the way how to prepare samples and the analysis itself is based on conversion of NDMH to N,N-dimethylhydrazone-4-nitrobenzaldehyde, its liquid extraction from water, concentration of the extract via evaporation and assay by the internal standard test.

Determination of hydrazine, monomethylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine by nonaqueous capillary electrophoresis with amperometric detection.

The present study is concerned with the application of nonaqueous capillary electrophoresis (NACE) with electrochemical detection (ED) to the separation and quantitative determination of hydrazine (Hy) and its methyl derivatives. The best performance of NACE-ED was found when using 4 mM sodium acetate/10 mM acetic acid/methanol: acetonitrile = 1:2 as the running buffer, with a bare platinum working electrode set at +1.0 V in an end-column amperometric detection cell. The choice and ratio of suitable solvents for the separation and injection media played an essential role for the performance characteristics of the method. The limits of detection for Hy, methylhydrazine, symmetrical dimethylhydrazine, and unsymmetrical dimethylhydrazine were 5, 2, 12, and 1 ng/mL, respectively. This is between one and two orders of magnitude lower than that achieved by previously reported CE-ED methods in aqueous buffer systems in conjunction with various types of chemically modified electrodes. The practical utility of the new NACE-ED methodology is demonstrated in terms of the determination of traces of Hys in spiked environmental samples containing a wide range of explosives and related compounds.