Field-Portable Vapor and Trace Residue Detection of Drugs and Explosives

Abstract

Detecting vapor from drugs and explosives is challenging due to their extremely low vapor pressures, often in the parts-per-trillion (pptv) to parts-per-quadrillion (ppqv) range. Atmospheric flow tube–mass spectrometry (AFT-MS) overcomes this limitation by extending ion–molecule reaction times, achieving detection of ppqv levels of vapor and femtogram levels of residue. However, the prior AFT-MS system was large (∼435 lbs.), limiting field deployment. To enhance portability, the AFT was integrated with a miniaturized, ruggedized, field-portable linear ion trap mass spectrometer (∼45 lbs.). This work presents results demonstrating the feasibility of portable AFT-MS for detecting illicit drugs and explosives in the field. Initial tests of the AFT with the portable MS were conducted to detect trace vapors from both solutions and residues. Real-time detection of fentanyl vapor from residue indicates detection levels of less than 100 ppqv based on the equilibrium vapor pressure of fentanyl. Adjusting ionization parameters, sampling speeds, trapping times, pressure levels, and system timing revealed pathways for further sensitivity enhancements. Early field tests at a U.S. Customs and Border Protection port of entry confirmed the ability of the system to simultaneously detect multiple drugs in complex mixtures. This is the first demonstration of portable vapor detection with AFT-MS, achieving subpptv-level sensitivity for real-time field detection of drugs and explosives.