10.1002/jms.1703
The research discusses the decomposition of N-hydroxylated compounds during atmospheric pressure chemical ionization (APCI) in liquid chromatography-mass spectrometry (LC-APCI-MS) experiments. The study aimed to understand and control artifact formation from N-hydroxylamines by APCI, which is crucial for accurate mass spectrometry analysis, particularly in the study of natural products and drug metabolism. The researchers used a synthetic N-hydroxylated tetraamine derivative as a model compound to investigate the reduction, oxidation, and water elimination reactions that occur during APCI, leading to the generation of amines, N-oxides, and imines. They found that the decomposition depends on the analyte concentration and the acidity of the solution, and they developed an MS method to unambiguously identify N–OH functionalities. The method was applied to study natural products, including polyamine toxins from spider venom and mayfoline, a cyclic polyamine derivative. The chemicals used in the process included high-performance liquid chromatography (HPLC) grade solvents such as acetonitrile, trifluoroacetic acid, formic acid, and aqueous ammonia solution, as well as synthetic compounds like [4-hydroxy-9-(2-nitrobenzenesulfonyl)-4,9-diazadodecane]1,12-diphthalimide and mayfoline. The study concluded that understanding in-source decomposition of N-hydroxylated amines can prevent misinterpretation of MS data and help distinguish N- from C-hydroxylation in compounds.
