Library search of mass spectra with a new matching algorithm based on substructure similarity.

A new matching algorithm for library searches of mass spectra is presented in this paper. The algorithm is based on the substructure similarity of substances. It emphasizes m/z positions rather than abundance values. 32 spectra, whose corresponding molecular weights are less than 200, were randomly selected from a mass library of 61,993 spectra and taken as targets of library search to illustrate the availability of this algorithm. The results show that the algorithm is better than the one built in a commercial instrument when there is no spectrum of the unknown in the library but there are similar ones.