Separation and determination of alkylglycosides by liquid chromatography with electrospray mass spectrometric detection

The separation of alkylpolyglycosides by liquid chromatography with electrospray mass spectrometric detection, using either an alkylamide or a cyanopropyl column, and acetonitrile/water mixtures as mobile phases, was developed. Using the alkylamide column and isocratic elution, the α- and β-epimers and ring isomers (pyranosides and furanosides) of the alkylmonoglycosides were resolved. The ring isomers were also resolved in a much shorter time using the cyanopropyl column with gradient elution. Using these columns, the isomers of the alkyldiglycosides and alkyltriglycosides were also partially resolved. The equilibration time was much shorter with the cyanopropyl column, which was selected to perform quantitation studies. The response factors increased more than an order of magnitude with the length of the alkyl chain, from the methyl to the decylmonoglycoside, and decrease largely for the dodecyl and tetradecylmonoglycoside. The limits of detection were of ca. 25 μM from the hexyl up to the dodecylmonoglycoside. The procedures were applied to the characterisation and determination of alkylmonoglycosides in toiletries.