DETERMINATION OF ALDITOLS AND CARBOHYDRATES OF FOOD INTEREST USING A SULFONATED MONODISPERSE RESIN-BASED COLUMN, COUPLED WITH PULSED AMPEROMETRIC DETECTION (PAD) AND POSTCOLUMN pH ADJUSTMENT

Carbohydrates such as glucose, fructose, sucrose, and sugar alcohols mannitol, sorbitol, and xylitol are widely distributed in various foods and beverages. In this work we developed a HPLC method for the determination of sugars and alditols, using a sulfonated monodisperse resin-based column in hydrogen form (PL Hi-Plex, 300 × 7.7 mm, from Polymer Laboratories), coupled with pulsed amperometric detection (PAD). Performing isocratic separation using water as the mobile phase, post column addition of 0.5 M sodium hydroxide was necessary to detect sugars and alditols by PAD. After the optimization of the operating conditions, the method was characterized and validated in terms of selectivity, repeatability, sensitivity, and accuracy. Furthermore, quantification of lactose, glucose, and galactose in lactose-hydrolyzed milk products was found to be highly accurate.