Various sweeteners were analyzed using LC/MS methods with a polymer-based HILIC column, HILICpak VG-50 2D. Two different eluents were compared: (A) alkaline solvent and (B) neutral solvent. The octanol-water partition coefficient of the analytes (log P, an indicator of compound’s polarity) and their retention times (tR) were plotted for each eluent condition. Their chromatograms are also shown below. Under the alkaline condition, a correlation between log P and retention time was observed; the lower the log P (higher polarity) of the analyte, the stronger the retention. On the other hand, under the neutral condition, the retentions of aspartame and acesulfame K were remarkably stronger. It can be assumed that aspartame and acesulfame K existed as anions under the neutral state, and the ion exchange effects with the amino group of the packing material strengthened their elution.
Sample : 2 μL, 50 μg/mL each
Column : Shodex HILICpak VG-50 2D (2.0 mm I.D. x 150 mm) Eluent : (A) CH3CN/0.5 % NH3 aq.=80/20 (B) CH3CN/50 mM CH3COONH4 aq.=80/20 Flow rate : 0.3 mL/min Detector : ESI-MS (SIM) Column temp. : 40 °C