Detection of some synthetic cannabinoids using GC-PCI-MS/MS: Comparison between isobutane and ammonia as reagent gases

Abstract

This study was conducted to investigate the ionization and fragmentation behavior of some synthetic cannabinoids (SCs) by examining the formation of their product ions using reagent gases having different proton affinities. Ammonia (NH3) and isobutane (i-C4H10) were employed as reagent gases in positive chemical ionization (PCI) mode using gas chromatography-tandem mass spectrometry (GC-PCI-MS/MS) to qualitatively detect SCs. Under usual operational conditions, the intensity of responses in terms of either ion abundances or peak areas obtained for protonated molecules is significantly influenced by the reagent gases. Ammonia produced two to three times greater responses than isobutane. Additionally, the results showed that the NH3–CI and i-C4H10–CI spectra do not contain the adduct ions for these SCs.