Fast Atom Bombardment Mass Spectrometric and Tandem Mass Spectrometric Investigation in Thioglycerol on Protonated Non-covalentAssociations of β-Cyclodextrin with 2-Acetyl,2-Propionyl-1-pyrroline and 5-Acetyl-2,3-dihydro-1,4-thiazine, Roast Smelling Odorants in Food. Role of the Matrix
✍ Scribed by Mele, Andrea; Panzeri, Walter; Selva, Antonio
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 292 KB
- Volume
- 32
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
2-Acetyl-1-pyrroline (1), 2-propionyl-1-pyrroline (2) and 5-acetyl-2,3-dihydro-1,4-thiazine (3), roast smelling odorants in food, form stable inclusion compounds with b-cyclodextrin. Fast atom bombardment (FAB) mass spectra of such complexes in thioglycerol showed abundant [ G + Hs + Mx + H ] ' ions, where G = guest (1, 2 or 3), Hs = host (b-cyclodextrin) and Mx = one molecule of matrix, consistent with protonated non-covalent threecomponent adducts, and nearly negligible 1 : 1 associations of the type [ G + Hs + H ] '. Collision-activated decomposition (CAD) experiments indicated that [ G + Hs + Mx + H ] ' are made of neutral b-cyclodextrin and protonated 1 : 1 guest-matrix adducts. The nature of these latter adducts was investigated by FAB mass spectrometric experiments on 1, 2 and 3 in thioglycerol without b-cyclodextrin. In all cases the most intense signals are due to [ G + Mx + H ] ' and [ G + H ] ', with a small contribution of to the total ion [
' a †orded protonated guest molecules as the base peak, consistent with the decomposition of protonated non-covalent 1 : 1 guest-matrix associations, possibly mediated by an intermolecular hydrogen bond. According to these data, there is a signiÐcant contribution of non-covalent threecomponent associations to [ G + Hs + Mx + H ] ' complexes, although the possibility of the formation of covalent guest-matrix adducts is not ruled out deÐnitely, as discussed in the text.