Mass Spectral Library Quality Assurance by Inter-Library Comparison
William E. Wallace, Weihua Ji, Dmitrii V. Tchekhovskoi, Karen W. Phinney, Stephen E. Stein
A method to discover and correct errors in mass spectral libraries is described. Comparing across a set of highly curated reference libraries compounds that have the same chemical structure quickly identifies entries that are outliers. In cases where three or more entries for the same compound are compared the outlier was almost always found to contain the error. These errors were either in the spectrum or in the chemical descriptors that accompany the spectrum. The method is demonstrated on finding errors in compounds of forensics interest in the NIST/EPA/NIH Mass Spectral Library. The target list of compounds to be checked was the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) list of seized drugs. Examples of errors that were found are described. A checklist of errors curators should look for when performing inter library comparisons is provided.
Journal of the American Society for Mass Spectrometry