Characterization of a chemical artifact in the liquid chromatographic determination of 3-butyn-2-one using the 2,4-dinitrophenylhydrazine method

This study reports the identification of a chemical artifact occurring in t he liquid chromatographic analysis of 3-butyn-2-one by means of the 2,4-din itrophenylhydrazine (DNPH) method. Besides the expected derivatization reac tion to the corresponding butynone DNPhydrazone, a rearrangement was observ ed, thus leading to the formation of 3-methyl-1-(2',4'-dinitrophenyl)pyrazo l (DNPP). Although the rearrangement product and the hydrazone can easily b e separated by means of liquid chromatography, problems arise from coelutio n of the pyrazol with the formaldehyde DNPhydrazone. Identification of the artifact by means of UV-Vis spectroscopy using dual wavelength or diode arr ay detection is discussed. (C) 2000 Elsevier Science B.V. All rights reserv ed.