Unusual MSⁿ fragmentation patterns of 2,4‐dinitrophenylhydrazine and its propanone derivative

Abstract

During the structural elucidation of carbonyl-2,4-dinitrophenylhydrazone derivatives in the low-ng range by multiple mass spectrometry combined with high performance liquid chromatography (HPLC/MS n ) some fragments were detected which were difficult to explain by ordinary fragmentation rules. Atmospheric pressure chemical ionization in the negative ion mode was applied. The ion formation was studied by labelling the parent compounds with D, 13C and 15 N and recording the MS/MS, MS 3 and MS 4 spectra. This allowed an investigation of the detailed fragmentation of 2,4-dinitrophenylhydrazine and its propanone derivative as well as the structures of the MS 2 and MS 3 product ions. A highly reactive product ion was found which undergoes unexpected reactions inside the ion trap of an HPLC/MS n system. In addition, reactions of MS n fragments with solvents or species generated in situ in the ion source and/or the ion trap were observed. It is demonstrated that unusual fragments in the MS/MS or MS n spectra of a compound may be formed by such reactions and that the eluent used for HPLC might have an influence on the observed fragmentation even if the mass spectrum itself is completely free from adducts.

Acrolein is formed from trienoic fatty acids in chloroplast: A targeted metabolomics approach

“…We prepared DNP derivatives of 24 types of carbonyls of 1-10 carbon chain length with or without an unsaturated bond (Table 1). In the MS/MS spectra of all these derivatives but that of malondialdehyde (MDA), the fragment ion of m/z 179, which is formed via the rearrangement of the DNP moiety (Kölliker et al 2001), was included within the ten most intensive signals (Supplemental data. Table S1).…”

Determination of aldehydes and ketones using derivatization with 2,4-dinitrophenylhydrazine and liquid chromatography–atmospheric pressure photoionization-mass spectrometry

“…Oehme et al have discussed the fragmentation schemes of the DNPH derivatives using APCI(−) in detail [13,17,18]. For the substances investigated with APPI-MS in this work, the fragmentation pathways were identical.…”

“…Derivatization of carbonyls with 2,4-dinitrophenylhydrazine. and coworkers later refined their method with respect to fragmentation pathways [17] and quantitative aspects [18]. Van den Bergh et al [19,20] applied the method to study oxidation products formed in the reaction between alpha-and beta-pinene and OH radicals.…”

Structure elucidation of nanogram quantities of unknown designer drugs based on phenylalkylamine derivates by ion trap multiple mass spectrometry

“…It seems that their formation is indicative of two methoxy groups in the meta position. The mechanism of formation was not studied further, however [2,30].…”

“…However, so far no general rules have been established for elucidation of a structure from the observed fragments, as for electron-impact ionization. Therefore, our group has started to develop structure-elucidation schemes for different compound classes such as carbonyl-dinitrophenylhydrazones [1,2], trichothecenes [3], aconite alkaloids [4], or oligomers of bisphenol A diglycidyl ether [5].…”