Canadian Society of Forensic Science

The use of cheminformatic databases in the forensic setting is nothing new. Numerous forensic labs create and maintain libraries of optical spectroscopy data (FT-IR) and mass spectrometry, typically EI-MS. Storage of accurate mass spectra, for controlled substances, from time-of-flight (AccuTOFTM) instruments with a Direct Analysis in Real Time (DART) ion source is increasing in occurance. These databases are only as good as their content. Thus the goal of this project is to create a free, forensically important, easy Web-accessible library with multiple spectral methodologies that allows electronic searching and comparison of unknown spectra against verified/peer-reviewed reference spectra. Specifically, the intention is to include FTIR spectra, nominal mass spectra (EI-MS), and accurate mass spectra (DART-MS).

Users upload spectra through a Web portal to an editorial review board where selected, external ‘collaborator reviewers’ evaluate the spectra based on established criteria. RTI staff, as the ‘database curator’, also review these data and the reviewers’ recommendations on whether the spectra should be accepted, rejected, or accepted with revisions. If all criteria are met the spectra is approved and moved into the cheminformatic database for public accessibility. Otherwise, the spectra are either rejected or the contributing user may be contacted to determine if better spectra can be submitted. Duplicity of a compound within the cheminformatic databases can be limited or eliminated as appropriate. Users can then perform full multi-spectral, chemical structure, and meta data searches across the database using a specific database field. Results may be downloaded as a report or as a data file to add to in-house collections where unrestricted access to the Internet is not permitted.

In the library’s current state there are dozens of users logging into the system on a regular basis to review the content. Inquiries from several state and federal labs have been made as to how they can contribute their in-house collections. As of right now the public database consists of 2,400 EI mass spectra previously housed in the American Academy of Forensic Sciences MS database and 224 compound records each with one to four DART spectra at different CID voltages collected simultaneously using function switching at VDFS. Inclusion of DART spectra into the database requires spectral evaluation and comparison by RTI and VDFS laboratories.

The resulting library will provide a standardized collection of reference spectra that can be used to promote new techniques, like the DART-AccuTOFTM, and allow facilities that do not have the staff to maintain their own extensive reference collections the ability to leverage the knowledge of the forensic community for unbiased sample identification.