Fragmentation Mechanism of Alkyl-monoglycosides by Mass Spectrometry

Abstract

Abstract Alkylmonoglycosides with different alkyl chain lengths (APG8, APG9, APG10 and APG14) were prepared by Fisher reaction of glucose with fatty alcohols. Excess alcohol was used to increase the possibility of producing alkyl monoglycosides products. Mass spectrometry with chemical ionization was used to confirm their structures as alkyl monoglycosides. Accordingly, the obtained signals at m/z = 293, 307, 321 and 377 corresponds to their protonated molecules. The base lines which are the most intensive signals in each spectrum at m/z = 145, 127, 141 and 197 represent the most abundant ions and define the pathway of their fragmentation mechanism. The mass 145 for APG8 is generated from the parent ion by elimination of the mass ROH followed by H2O. For this compound cleavage occurs at the C–O bond next to the glucose ring, while fragmentation of alkyl monoglycosides with carbon number 9, 10 and 14 occurs at the O–R bond releasing the alkyl cation R of the aglucone moiety (CnH2n+1) along with large fragment ions characteristic of the glucose moiety.