2C-O1-1040 PDF
Hydrogen rearrangement rules based in silico fragmentation for small molecule identification
We propose nine rules of hydrogen rearrangement in low-energy collision-induced dissociation (CID) for the comprehensive identification of small molecules in metabolomics. The rules are basically derived from the classic even-electron rule and the rule of mass shift, but are refined and extended for four heteroatoms, oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S) based on our extensively curated database records. By applying these rules we could annotate 78.9% of MS/MS spectral peaks in the MassBank public repository and identify bond- cleavage positions. Determination of bond-cleavage positions not only contributes to spectral analysis but also improves the reliability of available computational methods that exploit spectral information. With MS/MS spectra annotations by the rule, our software program could distinguish structural isomers with 84.8% accuracy.