RAPID PROFILING OF AUTHENTIC FORENSIC EVIDENCE VIA PAPER CONE SPRAY IONIZATION EMPLOYED ON PORTABLE MS INSTRUMENTATION
Ambient MS methods have been shown applicable to forensic chemical analysis, but bear further refinement to allow rapid profiling of authentic evidence types. This is of particularly interest when considering deployment on portable MS instrumentation with reduced vacuum capabilities, as instrumental hygiene and carryover are of increased concern. Paper cone spray ionization (PCSI) featuring on-board filtration has been demonstrated as robust to the analytical constraints of authentic forensic evidence screening, particularly towards bulk phases (e.g. powder-based drugs, tablets, paraphernalia, etc.). Efficacy towards processing and identification of evidentiary seizures with a portable MS system is presented herein. All investigations employed the FLIR Systems AI-MS 1.2, a portable CIT-based MS system featuring a continuous sampling capillary inlet. For PCSI-MS, the source design featured wax paper folded to produce a triangular pyramidal structure that serves as a reservoir for spray solvent (i.e. 1:1 methanol:water w/ 0.1% formic acid). Samples of interest are first placed into a Whatman filter paper insert, which is folded akin to a druggists' fold and then placed inside the solvent reservoir. This paper insert serves to filter and retain inert/insoluble material during analysis. Application of spray solvent and high voltage extracts analytes of interest and induces ionization via ESI-like processes from the pyramidal egress. Samples analyzed though this work included authentic evidence provided through local police and vice squad contacts (e.g. abused pharmaceutical tablets, psychotropic plants, paraphernalia, adulterated food products, etc.) and proof-of-principle, lab generated scenarios. Included in this dataset are 40+ pharmaceutical table compositions, including: over-the-counter (OTC), prescription-only, known precursors to clandestine drug synthesis, scheduled controlled substances, and clandestinely-produced/counterfeit tablets (e.g. MDMA, alpha-PVP, etc.) All evidence types were analyzed with minimal preparation and handling. MS and MS/MS data were employed for analyte identification. PCSI-MS and MS/MS spectra were similar to that reported for spray ionization techniques in that most analytes were observed as the protonated molecule, [M+H] +. Cutting agents and adulterants were also successfully identified in several evidence types. Also presented will be the efficacy of PCSI-MS on portable MS instrumentation towards vice squad operations. Through interactions with local undercover units, our methodology was utilized to assist in the identification of recent seizures and drug buys, and in some cases, test the accuracy or remove the ambiguity of officer-employed colorimetric testkit results. The accuracy of PCSI-MS identifications was then assessed through comparison with subsequent identifications made by state-level forensic laboratories.
Stelmack, Ashley, "RAPID PROFILING OF AUTHENTIC FORENSIC EVIDENCE VIA PAPER CONE SPRAY IONIZATION EMPLOYED ON PORTABLE MS INSTRUMENTATION" (2019). University Research Symposium. 216.