Determination of Sugars by Anion Exchange Chromatography Using a Dual Eluent Generator

PS1 Poster session 1 Odd numbers
Location (hall): 
Start/end time: 
Monday, July 1, 2019 - 15:45 to 17:15

Sean Austin1

1Nestle Research, Lausanne, Switzerland

High performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) is a powerful tool for the analysis of mono- and oligosaccharides. Over other chromatographic techniques it has the advantage of high sensitivity and excellent resolving power without the need for derivatisation of the analytes. Perhaps one of the most time-consuming tasks of setting up the system is preparation of the mobile phase, since it requires extensive degassing of the eluents to eliminate carbonate, which binds strongly to the stationary phase, and thus causes problems for retention time stability. Several years ago, the eluent generator was introduced for production of KOH, however since carbohydrates often need an additional gradient of sodium acetate for elution, the KOH generator was not widely implemented in labs performing carbohydrate analysis. Last year a dual eluent generator (Dual EG) was introduced, able to generate gradients of both KOH and potassium methane sulfonate (KMSA). Such a system is suitable for the analysis of a wide range of carbohydrates. The system is designed to work with 1mm diameter columns, running with a typical flow rate of 0.05 mL/min, the system can generate a maximum concentration of 200 mM KOH or 200 mM KMSA, or a mix of the two with a combined maximum concentration of 200 mM. 

One of the most common analyses required in the food industry is the analysis of sugars (glucose, galactose, fructose, sucrose, lactose and maltose). The separation and quantitative determination of these six sugars is easily performed on a CarboPac PA20 (7µm, 3 x 150 mm) using a gradient of sodium acetate and NaOH. Here we demonstrate that the same analysis can be performed on a prototype CarboPac PA20 (4µm, 1 x 150 mm) using a gradient of KMSA and KOH. We also observed that while it is necessary to use post-column addition of NaOH when running the analysis on a standard system, it was not necessary on the system using the 1 mm column.  The system was also applied for the analysis of fructans in infant formula according to AOAC 2016.14, and results were comparable to the standard method.