Improving the Analysis of Carbohydrates Using Temperature and Sample Preheating

The use of elevated temperatures is a common tool for the analysis of carbohydrates using ligand-exchange chromatography. Sample preheating can further enhance peak efficiency and improve the analysis of carbohydrates.

Ligand-exchange chromatography is a common technique for the analysis of carbohydrates using polymeric based columns. Since these types of HPLC columns require only water as the eluent, laboratories that prefer to not introduce solvents into their environment will use this type of "green technology" as a viable alternative for the analysis of many common samples containing carbohydrates. Columns packed with gels (low cross-linked, microporous, polystyrene-divinylbenzene polymer) typically require elevated temperatures for optimal peak efficiency. Peak efficiency can be further enhanced with the use of a column oven equipped with a sample preheat device or a plug-in preheat coil.

Table I: Temperature effect on glucose efficiency

Experimental Conditions

Column: Benson Polymeric BP-800 Ca (PN 8000-0)

Mobile phase: DDI water

Oven temperature: 60 °C, 65 °C, 70 °C, 80 °C, 85 °C

Flow rate: 0.5mL/min

Detector: Refractive Index

Column oven: Benson Polymeric column oven

Sample preheat: Benson BP-PH Preheater (PN 5050-0)

Table II: Temperature effect on fructose efficiency

Results

Tables I and II show the increase in peak efficiency for both glucose and fructose as temperature is increased when using a calcium form ligand-exchange HPLC column (Benson BP-800 Ca). Peak efficiency is further enhanced with the use of a preheat device for sample heating prior to entering the column. Figures 1 and 2 are a visual presentation of the increase in efficiency for glucose and fructose.

Figure 1: Glucose and fructose peaks with pre-heat (BP-800 Ca, (300 × 7.8 mm), 85 °C, 0.5 mL/min, water eluent). Figure 2: Glucose and fructose peaks without pre-heat coil (BP-800 Ca, (300 × 7.8 mm), 85 °C, 0.5 mL/min, water eluent).

Conclusion

Elevated temperatures are required for optimal peak efficiency when using polymeric ligand-exchange HPLC columns. By supplementing elevated temperature with a sample pre-heat device, peak efficiency is further enhanced, sometimes dramatically.

Benson Polymeric Inc.
9475 Double R Blvd., Suite 7, Reno, NV 89521
tel. (775) 356 5755, fax (775) 356 6305
Website: www.bensonpolymeric.com