Detecting Fentanyl Analogs by Combining Surface-Enhanced Raman Spectroscopy (SERS) and Paper Spray Mass Spectroscopy (PS-MS).

Introduction: Many fentanyl analogs are developed and mixed with other illicit drugs, such as cocaine and heroin. Detecting fentanyl and fentanyl analogs in these illicit drug mixtures gains more importance. Most confirmatory procedures require time-consuming and expensive, highly sophisticated laboratory equipment and experimental procedures, which can delay critical information that might save a victim or identify a suspect. In this project, we propose miniaturizing and accelerating this process by combining SERS analysis and mass spectrometry on a single microfluidic device. This procedure, known as paper spray mass spectrometry (PS-MS), can isolate fentanyl analogs from even complex drug mixtures. Thus, we propose to develop a novel device capable of simultaneously detecting fentanyl and fentanyl analogs in illicit drug mixtures. Methods: For this aim, first, a dual-purpose plasmonic paper substrate will be developed and optimized by soaking the filter papers into the synthesized bimetallic (Au-Ag) nanostars. The various images will be taken to define the characteristics of these paper substrates. Then, a procedure for drug screening by Raman will be combined with paper spray mass spectrometry (PS-MS) confirmation. Finally, this newly developed method will be used in seized drug samples. Results: The soaking time of the filter paper is affecting the enhancement. As the papers stay in the nanostar solutions more (up to 6 days), the enhancement of the peaks gets better. Different illicit drugs such as fentanyl, fentanyl analogs, cocaine, heroin, and methamphetamine can be detected on these filter papers by portable Raman spectroscopy. Optimizing the PSI-MS method is still in process. Conclusions: Coupling portable SERS and PSI-MS methods will provide strong confirmatory results for real-world samples and drug mixtures. The experimental results obtained in this project can be readily implemented in field applications and in smaller laboratories, where inexpensive portable Raman spectrometers are often present and are used in drug analysis.