With increasing backlogs and more complex samples, forensic chemistry laboratories need new technologies that rapidly provide accurate analytical results. Many laboratories are adopting Direct Analysis in Real Time Mass Spectrometry (DART-MS) to meet this need. DART-MS enables laboratories to obtain mass spectra, or molecular “fingerprints,” from samples in seconds instead of tens of minutes. Because this technique is highly sensitive, very little of the sample is handled or consumed during analysis. This reduces the risk of accidental exposure when analyzing highly toxic compounds such as fentanyl.
We are developing a suite of methods, software tools, and resources to help forensic laboratories adopt and implement DART-MS and other ambient ionization mass spectrometry (AI-MS) techniques. These include databases, mass spectral search tools, analytical methods, and example validation documents.
UPDATE: The NIST DART-MS Forensics Database 2020 is now available for download from the NIST website. This is an evaluated collection of mass spectra of seized drugs, cutting agents, and related compounds.
This project is part of NIST’s ongoing effort to help labs detect and identify synthetic opioids and other drugs efficiently, reliably, and safely. If you have any questions, please contact DARTdata@nist.gov.
The development of methods, software tools, and resources for forensic laboratories using DART-MS or other AI-MS techniques is a collaborative effort between the Surface and Trace Chemical Analysis Group (STCAG), the Mass Spectrometry Data Center (MSDC), and practicing forensic laboratories across the country. These efforts are aimed at addressing many of the common roadblocks for adoption of new technologies by forensic laboratories including development of instrumental methods, validation procedures, workflows, spectral databases, and data analysis tools. The goal of this work is to create and provide these resources to the community.
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Spectral Databases, Search Software, and Data Analysis Tools
While DART-MS is capable of rapidly analyzing samples, examining the resulting data can be time-consuming and cumbersome. Additionally, as with all mass spectrometry techniques, identification of compounds in the sample is often completed by comparing a sample spectrum to a library of known spectra. To assist forensic laboratories with these efforts, the development of a suite of data analysis tools is underway that will provide spectral databases, spectral searching, and other features.
The central component of this suite is the NIST DART-MS Forensics Database. The database is an evaluated collection of mass spectra of compounds of interest to the forensics community (e.g. seized drugs, cutting agents, etc.) collected either by NIST scientists or by collaborating laboratories. The database, which is freely available and regularly updated, provides mass spectra for over 600 compounds. The database, which can be downloaded at https://chemdata.nist.gov/dokuwiki/doku.php?id=chemdata:dart-library, can used with NIST MS Search software or is available as a general-purpose structure data file (.SDF) (doi.org/10.18434/mds2-2313). To complement the spectral database a new DART-MS specific database viewer is under development along with DART-MS specific mass spectral search software.
Methods for Analysis
Development of methods for the analysis of different sample types is often one of the first things that needs to occur with the implementation of a new technique. To assist laboratories in these efforts, a suite of methods for the analysis of different compound and sample types has been, and continues to be, developed. Methods for the detection of fentanyl and other opioids, explosives, rodenticides, and even alcoholic beverages have been established. These efforts also include development and investigation of modification to DART-MS, such as thermal desorption (TD)-DART-MS or infrared thermal desorption (IRTD)-DART-MS which can provide more reproducible, more sensitive analysis of a wider range of compounds of interest.
Method-related publications include:
To further assist in providing the tools necessary for technology adoption, other, more practical, resources are also being developed. These resources include example documentation, such as validation plans and standard operating procedures, training resources such as workflows, and review publications that provide overviews of the technology, applications, and ongoing research.