Improving Non-Contact Fentanyl Detection by IMS using a novel pre-concentrator

Detecting dangerous drugs in the field is crucial for public safety and law enforcement. Ion Mobility Spectrometry (IMS), with swab sampling, is commonly used in field settings but poses risks to first responders, especially with potent drugs like fentanyl, where even nanogram amounts can be lethal. Using IMS with vapor sampling offers a safer approach, but detecting fentanyl at trace levels is challenging due to its low vapor pressure. This research aims to improve IMS detection by developing a novel pre-concentrator using Silicon Nanowires (SiNWs) coated with an acrylate-based polymer. N-phenylpropanamide (NPPA), a key vapor component found in fentanyl's headspace, is used as a surrogate for IMS detection. From a library of acrylate-coated SiNWs capable of analyte pre-concentration, selected acrylate polymers were screened using a Quartz Crystal Microbalance (QCM) to assess their NPPA pre-concentration ability. Ethylene Glycol Methyl Ether Acrylate (EGMEA) was identified as the most effective. To validate its performance, filter paper coated with EGMEA was sampled with 100 mg of fentanyl over a week followed by analysis using an optimized Thermal Desorption-Gas Chromatography/Mass Spectrometry method, confirming the polymer’s effectiveness in collecting NPPA vapor. Coated filter papers sampled with confiscated fentanyl from Kentucky and Maryland State Police crime labs were analyzed, validating that EGMEA is suitable for NPPA pre-concentration and NPPA is an effective target vapor surrogate. The current focus is to optimize a SiNW array coated with EGMEA for integration into a microchip compatible with a commercially available handheld IMS enabling the use of the pre-concentrator in field settings. This pre-concentrator is expected to enhance trace fentanyl detection by selectively capturing NPPA vapor, addressing the urgent need for improved sensitivity in non-contact detection and this has the potential to expand to other dangerous drug classes.