1-Methyl-1-(2,4-dinitrophenyl)hydrazine as a New Reagent for the HPLC Determination of Aldehydes

The synthesis and first application of an N-alkylated hydrazine reagent for the HPLC determination of aldehydes and ketones is described. 1-Methyl-1-(2,4-dinitrophenyl)hydrazine (MDNPH) reacts with aldehydes to give the corresponding hydrazones in the presence of an acid as catalyst. In contrast to other hydrazine reagents, MDNPH is oxidized by both ozone and nitrogen dioxide quantitatively to N-methyl-2,4-dinitroaniline (MDNA), which can be separated from the hydrazones of the lower aldehydes by means of HPLC. Unexpected elution orders are observed for the 1-methyl-1-(2,4-dinitrophenyl)hydrazones compared to those of 2,4-dinitrophenylhydrazones. Dual-wavelength detection is employed as a means for identification of different groups of the hydrazones and MDNA.