Letter: Fast Atom Bombardment,Electrospray,Ionspray and Tandem Mass Spectrometry of 1:1 β-Cyclodextrin/5-Methoxytryptamine Hydrochloride Host—Guest Complex: Host Protonation and Fragmentation Due to Guest Deamination

The 1:1 inclusion complex of β-cyclodextrin (βCD) with 5-methoxytryptamine (5MTA) hydrochloride was studied by mass spectrometry (MS) and tandem-MS with fast atom bombardment (FAB), electrospray (ES) and ionspray (IS) ionisation and triple quadrupole or ion trap analysers. A protonated 1:1 βCD/MTA gaseous association was always observed; the protonated species of deaminated 5MTA and of some typical βCD fragments were obtained, in addition to the expected protonated 5MTA, as tandem-MS dissociation products. A reaction pattern starting from the deamination of protonated 5MTA, as a recently described high pressure chemical ionisation or ES process of primary amines, was suggested, which accounts for the formation of excited protonated βCD and its fragmentation by tandem-MS, even under unimolecular conditions.