Broad spectrum infrared thermal desorption of wipe-based explosive and narcotic samples for trace mass spectrometric detection

Abstract

Wipe collected analytes were thermally desorbed using broad spectrum near infrared heating for mass spectrometric detection. Employing a twin tube filament-based infrared emitter, rapid and efficiently powered thermal desorption and detection of nanogram levels of explosives and narcotics was demonstrated. The infrared thermal desorption (IRTD) platform developed here used multi-mode heating (direct radiation and secondary conduction from substrate and subsequent convection from air) and a temperature ramp to efficiently desorb analytes with vapor pressures across eight orders of magnitude. The wipe substrate experienced heating rates up to (85 ± 2) °C s−1 with a time constant of (3.9 ± 0.2) s for 100% power emission. The detection of trace analytes was also demonstrated from complex mixtures, including plastic-bonded explosives and exogenous narcotics, explosives, and metabolites from collected artificial latent fingerprints. Manipulation of the emission power and duration directly controlled the heating rate and maximum temperature, enabling differential thermal desorption and a level of upstream separation for enhanced specificity. Transitioning from 100% power and 5 s emission duration to 25% power and 30 s emission enabled an order of magnitude increase in the temporal separation (single seconds to tens of seconds) of the desorption of volatile and semi-volatile species within a collected fingerprint. This mode of operation reduced local gas-phase concentrations, reducing matrix effects experienced with high concentration mixtures. IRTD provides a unique platform for the desorption of trace analytes from wipe collections, an area of importance to the security sector, transportation agencies, and customs and border protection.

Ambient Pressure Laser Desorption—Chemical Ionization Mass Spectrometry for Fast and Reliable Detection of Explosives, Drugs, and Their Precursors

“…Table 3 summaries compared analytical techniques and achieved LODs. In detail, the APLD allows similar LODs compared to Raman spectroscopy [36], ion mobility spectrometry [37], and thermal desorption (TD) MS [38,39]. Compared to APLD, desorption spray ionization (DESI) achieves better LODs for explosives [40] with the disadvantage of a more complex setup and the need of a liquid solvent supply.…”

“…TD MS allows for the detection of 5 ng of TNT while APLD can detect 500 pg. For cocaine [45], a LOD of 388 ng and 2 ng for MDMA [38] is reported.…”

Forensic Analysis and Differentiation of Black Powder and Black Powder Substitute Chemical Signatures by Infrared Thermal Desorption–DART-MS

“…34–36 The recent development and progression of infrared thermal desorption (IRTD) of wipe- based collections enables the generation of an inherent temperature ramp during a discrete multi-second infrared emission interval for analyte thermal desorption. 35,37 The temperature profiles generated by the IRTD notably enabled the thermal desorption of species at their optimal temperatures, i.e. , more volatile species at lower temperatures, while still achieving elevated temperatures necessary for the desorption of refractory inorganic oxidizers.…”

Detection of fuel‐oxidizer explosives utilizing portable capillary electrophoresis with wipe‐based sampling

“…3A, the chlorate signal intensity increased as the deposited sample location approached the outlet port, used to withdraw the extracted sample solution for downstream processing. The highest signal intensities resulted from printed locations between coordinates (18,25) and (18,20). Additionally, printed locations closest to the inlet port for introduction of the extraction buffer, towards coordinate (10,10), exhibited decreased signal intensities.…”

“…Although IMS is advantageous for organic explosives, detection of nonvolatile inorganic explosives is challenging due to the lower vapor pressures of refractory inorganic oxidizer components. Improvements toward inorganic-based explosives detection have focused on increasing the sensitivity for sulfur identification [14], utilizing acid-enhanced evaporation [15,16], and employing instrument modifications for reaching increased thermal desorption temperatures [17][18][19]. Peng et al were able to achieve <10 ng sensitivities for nitrate, chlorate, and perchlorate using acid enhancement and analysis times within 5 s [15].…”