Government agencies seek to stop the transport and use of illicit substances, such as narcotics and organophosphorus compounds like pesticides and nerve agents. Detection of vapors may hold the key in detecting illicit substances in cargo containers or other concealed conveyances. Pacific Northwest National Laboratory’s vapor detection system can do just that: accurately detect organophosphorus compounds and narcotics at ultra-low levels never before possible in the presence of other chemical vapors.

The approach employs an ion detector and unique ionization chemistry that includes chemical dopants or reactant ions which improve selectivity. Increased reaction time between the ionization source and the ion detector provides the remarkable detection limits. The ion detector may be a mass spectrometer (MS) or an ion mobility spectrometer (IMS). The preferred instrument is an atmospheric flow tube (AFT) MS. The flow tube is a reaction region defined between an ionization source and the ion detector. The AFT has been demonstrated with an MS as the ion detector and will likely work with an IMS as the ion detector.

The method includes introducing a vapor sample containing at least one analyte and at least one dopant into the flow tube, ionizing the vapor sample in the flow tube with an ionization source, and introducing the ionized vapor sample into the reaction region of the flow tube. In laboratory studies, the AFT-MS detected organophosphorus compounds at concentrations at 100 parts-per-quadrillion (ppq) or better. The instrument also detected illicit drugs at concentrations at 160 ppq or better. These results are orders of magnitude lower than any current technology.

Applicability

The vapor detection system detects organophosphorus compounds (pesticides and nerve agents) and narcotics (for example, fentanyl, heroin, cocaine, and methamphetamine). The system could be used either onsite (for example, airport security or port of entry screening) and in a laboratory setting.