Cannabis identified ambiently

Cannabis has been identified by direct analysis of the plant material using an ambient mass spectrometry technique which can distinguish between active and inactive components. Tiina Kauppila and colleagues from the University of Helsinki and the Forensic Laboratory of the National Bureau of Investigation at Vantaa used desorption atmospheric pressure photoionisation (DAPPI) to analyse herb samples, as described in Drug Testing and Analysis.

Most ambient mass spectrometry techniques cannot discriminate between the active ingredient tetrahydrocannabinol (THC) and the inactive component cannabidiol (CBD) and this was the same when DAPPI was conducted with acetone as the solvent. Protonated molecules of each compound were observed but their product ion spectra were identical. However, with toluene as solvent, the molecular ions were produced and they gave notably different product ion spectra for the two components, allowing them to be distinguished.

The method provides a rapid aternative for cannabis testing that eliminates false positives due to the presence of CBD.