On-line liquid chromatography–electrospray ionisation mass spectrometry for κ-carrageenan oligosaccharides with a porous graphitic carbon column

Enzymatically digested oligosaccharides of κ-carrageenans were separated on a porous graphitic carbon (PGC) column and characterised on-line by electrospray ionisation mass spectrometry (ESI–MS). Two different developing ions were applied. Among them ammonium hydrogencarbonate showed more eluting power as it should on normal anion-exchange stationary phases. The oligosaccharides were detected by ESI–MS as fully deprotonated oligosaccharides.