T13N1

I.G. Zenkevich, T.I. Pushkareva

It is shown that the use of dimethylformamide dimethylacetal for derivatization of analytes in gas chromatography/mass spectrometry cannot be restricted by the known conversion of carboxylic acids, phenols, and thiols into their methyl esters (ethers), as well as the conversion of non-volatile amino acids (and C-amino compounds of other classes) into their dimethylaminomethylene derivatives. The appli­ca­tion of this reagent in derivatization of hydrazine derivati­ves and volatile carbonyl-containing analytes is considered. In the last case the reaction takes place selectively at the expense of CH2 and/or CH3 groups in α-position to the carbonyl fragment. The principal predesti­na­tion of derivatization of such analytes is their characteris­tics by differen­ces of gas chromatographic retention indi­ces (∆RI) of reaction pro­ducts and initial subs­tra­tes. The ranges of variations of such incre­ments ∆RI appea­red to be various for different sub-groups of carbonyl compounds; it permits us to define their structures more precisely. The mass spectra of C-dimethylaminomethylene derivatives of some carbonyl compounds, preferably 2-substituted 1-methyl- and 1-aryl-3-(dimethylamino)prop-2-en-1-ones, revealed intense
M – 17 peaks. The appearance of these signals can be explained by a hydrogen atom migra­tion and formation of the [М – ОН]+ ions.

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Keywords: газовая хроматография диметилацеталь диметил­фо­р­м­амида identification индексы удерживания карбонильные соединения масс-спектры С-DMAM производные

Categories: T13N1