OPTIMIZATION OF PLASMONIC PAPERS FOR TWO-TIERED DRUG ANALYSIS ON A PORTABLE, SERS-PSI-MS PLATFORM
Evidentiary backlogs in forensics laboratories are replete with suspected illicit substances; streamlining their analysis has the potential to save valuable time and government funding. Part of the delay is owing to the insufficiency of field-test methods, often limited to colorimetric kits that suffer false positives and subjective interpretation. It is our belief that the coupling of a portable Raman and mass spectrometer (MS), both SWGDRUG "Category A" techniques - in addition to the utilization of surface enhanced Raman spectroscopy (SERS) for trace analysis - offers a promising analytical solution to the drawn-out process of screening substances and generating prosecutorial evidence. Paper substrates are an ideal candidate for sample collection: embedded with plasmonic nanoparticles they are capable of SERS detection at nanogram levels, and samples can be sprayed directly into the MS via paper spray ionization (PSI-MS). The present address highlights recent efforts in the optimization of gold nanoparticle (AuNP) embedded papers. These include SERS limits of detection on papers with different nanoparticle morphologies for 5 representative drugs (2C-B, cocaine, fentanyl, hydrocodone, and JWH-018). While the use of spherical or anisotropic AuNPs allows detection limits in the range of 10 - 100 nanograms for the compounds studied, anisotropic AuNP papers show higher signal enhancement and less complicated background signals. Additionally presented are demonstrations of SERS-PSI-MS from a single sample, using the aforementioned drugs. This has been done sequentially (SERS then PSI-MS), as well as simultaneously (SERS and PSI-MS in tandem) to evaluate spray solvent effects on SERS acquisition and laser effects on PSI-MS. Further investigations highlight not only the compatibility of the two instrumental techniques, but also their complementarity. The structural isomers of APDB, indistinguishable with PSI-MS, are identifiable by SERS via shifts in vibrational bands. This project was supported by Award No. 2017-R2-CX-0022, awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect those of the Department of Justice.
Burr, Daniel, "OPTIMIZATION OF PLASMONIC PAPERS FOR TWO-TIERED DRUG ANALYSIS ON A PORTABLE, SERS-PSI-MS PLATFORM" (2019). University Research Symposium. 172.