Application of direct analysis in real-time mass spectrometry (DART-MS) in forensic science: a comprehensive review

Abstract

Background As the rate of crime is constantly increasing, the workload on the forensic analyst also piles up. The availability of a limited number of seized samples makes it crucial to directly analyze the sample, thereby preventing wastage in the prior steps of sample preparation. Due to such needs, the forensic community is consistently working on broadening the usage of direct analysis in real-time mass spectrometry (DART-MS). DART-MS is a relatively new technique for rapid mass spectral analysis. Its use for chemical analysis credits its ability to analyze the sample at atmospheric pressure. Main body This article gives insight into the ionization mechanisms, data analysis tools, and the use of hyphenated techniques like thermal-desorption-DART-MS, infrared-thermal-desorption-DART-MS, Joule-heating thermal-desorption-DART-MS, etc. This review summarizes the applications of DART-MS in the field of Forensic Science reported from 2005 to 2021. The applications include analysis of drugs, warfare agents, gun-shot residues, ink differentiation, and other forensically relevant samples. The paper also presents the relation between the type of DART-MS technique and the ionization mode used for a particular class of compounds. Conclusion The review follows that the high-resolution mass-spectrometers or low-resolution mass-spectrometers systems in the positive or negative mode were highly dependent on the type of analyte under investigation. Drugs, inks, dyes, and paints were mainly analyzed using the positive ionization mode in the HRMS technique. The examinations of fire accelerants predominantly used the positive ionization mode in the LRMS technique. Moreover, the limit of detection values obtained from the qualitative screening of street drugs were of ppb level, indicating high sensitivity of DART-MS. Considering the work done in the past years, there are potential future research needs of this technology, especially in forensic science. Graphical Abstract

Uncovering Factors That Affect the Efficiency of Azo Dye Synthesis in Organic Chemistry Laboratory

“…The same impurity spots could also be identified when β-naphthol was replaced by either phenol or resorcinol (Figure S4), suggesting that they could originate from aniline or its diazotized product. Direct analysis in real time (DART)-MS , was used to analyze these species by scraping the silica particles containing the bands of these species and directly introducing them to the sample inlet. It was found that both impurities had the same molecular mass (specifically m / z 198.1028 and 198.1029 for impurities #1 ( R f = 0.58) and #2 respectively ( R f = 0.34)).…”

Interpol Review of Drug Analysis 2019-2022

“…2021 a prototype of a new Inverted Library-Search Algorithm (ILSA) that enhances presumptive identifications of mixture components using a series of in-source collision-induced dissociation mass spectra collected through DART-MS ( https://github.com/asm3-nist/DART-MS-DST ) [ 1018 ]; creation and release of the new NIST DART-MS Forensics Database and the steps taken to automate the data evaluation process [ 1019 ]; 2022 review of the application of DART-MS in forensic science [ 1020 ].…”

Molecular Characterization of Hydrocarbons in Petroleum by Ultrahigh-Resolution Mass Spectrometry

“…The ionization mechanism of DART is that a neutral or inert gas (e.g., nitrogen or helium) is discharged at atmospheric pressure to generate excited atoms, which are rapidly heated and accelerated by an electric field to desorb and instantaneously ionize the compound to be measured on the sample surface. The connection of the DART source to HRMS allows direct analysis of the sample in real time [81]. Dane et al used DART in negative-ion mode with time-of-flight MS to characterize n-alkanes with larger carbon numbers (C > 18), producing mainly [M + O 2 ] −• and with less fragmentation, achieving soft ionization of hydrocarbons to some extent [82].…”