Abstract: A system for detecting a chemical substance of interest among a plurality of different chemical substances comprises an inlet, an ionization module, a high-field asymmetric waveform ion mobility spectrometry (FAIMS) cell, and optionally a detector. A focussing module and/or a flow control gas supply can be provided. The system has example applications for molecules including ?-9-tetrahydrocannabinol (THC), its metabolites and/or other substances of interest from a breath of a subject or from a breath sample obtained from a subject.

Abstract: A system for collecting cannabis and the psychoactive component tetrahydrocannabinol from a sample of exhaled breath is disclosed. Single or multiple exhaled breaths are conditioned by removing contaminants, and regulating flow rate and/or pressure to collect a sample of tetrahydrocannabinol for timely local or remote analysis. The cannabis detection system comprises a containment trap for removing interfering materials from the breath of the subject and a collection component for sampling components of breath introduced into the system through the containment trap for analysis to determine a presence of THC in the breath.