The improved ‘GC–MS Search’ has now been modified to support RI data as an additional search constraint. Users may input an RI value with a default 3% tolerance. If the RI option is chosen, users must also choose any one of three types of GC columns as the RI values are specific to the column type. Additionally, the type of chemical derivatization(s) used must be provided. Users have the option to indicate no derivatization, TMS derivatization, or TBDMS derivatization. If no RI input value is provided, the GC–MS search function will still perform its regular EI-MS-only search without the RI constraint. Matched compounds for DrugBank's new ‘GC–MS Search’ are ranked according to their spectral similarity and RI similarity.
