# Hydralazine derivative of aldehyde: A new type of [M - H]ion formed in electrospray ionization mass spectrometry.
> エレクトロスプレーイオン化質量分析法におけるヒドララジン-アルデヒド誘導体の新規脱水素イオン[M－H]⁺の生成機構


## Abstract

This study identified a previously unreported dehydrogenated ion species, [M-H]+, arising from hydralazine derivatives of aldehydes analyzed by electrospray ionization mass spectrometry (ESI-MS). The phenomenon was observed to be independent of liquid chromatography mobile phase composition and ESI source settings. Systematic investigation of multiple hydralazine-aldehyde derivatives revealed that the [M-H]+ ion formed specifically when the aldehyde possessed an sp3-hybridized carbon bearing a hydrogen at the alpha position. In contrast, the hydralazine derivative of acetone produced only the conventional [M+H]+ ion. A mechanistic proposal was advanced in which the protonated species [M+H]+ undergoes loss of a neutral H2 molecule to yield the observed [M-H]+ ion. Density functional theory (DFT) calculations provided computational support for this proposed ionization pathway.

### Mechanism

DFT calculations support a mechanism in which the protonated ion [M+H]+ loses a neutral H2 molecule to generate the dehydrogenated [M-H]+ ion, a process specific to aldehyde derivatives with an sp3 alpha-carbon bearing hydrogen.

## Bibliographic

- **Authors**: Xiao HM, Wang X, Yang X, Zheng F, Feng YQ
- **Journal**: J Mass Spectrom
- **Year**: 2019
- **PMID**: [30650224](https://pubmed.ncbi.nlm.nih.gov/30650224/)
- **DOI**: [10.1002/jms.4330](https://doi.org/10.1002/jms.4330)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 30650224. https://h2-papers.org/en/papers/30650224
> **Source**: PubMed PMID [30650224](https://pubmed.ncbi.nlm.nih.gov/30650224/)