Submitted to: Sugar Processing Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 16, 1998
Publication Date: N/A
Interpretive Summary: Millions of dollars are lost each year in the sugar industry due to chemical losses of sucrose in sugar manufacture and refining. Such losses are difficult to measure and have necessitated the need for very accurate values of sugar concentrations. A method called ion chromatography has gained wide acceptance as the preferred technique for measuring sucrose, glucose and fructose concentrations in industrial samples, including juices and liquors. An in-depth investigation of this technique was undertaken and many improvements on the method have been developed which will benefit the sugar industry in their efforts to accurately measure sucrose losses during processing. Guidelines and troubleshooting for improved quantitation of sugars are provided.
Technical Abstract: Ion chromatography with integrated pulsed amperometric detection (IC-IPAD) is gaining wide acceptance as the preferred technique for analyzing sucrose, glucose and fructose in industrial sugar samples, including juices and liquors. This article describes the further optimization of IC-IPAD to more accurately and repeatedly measure the amounts of sucrose, glucose and fructose in multiple industrial sugar samples. Using either a 16 to 160mM NaOH eluent gradient or a 100mM NaOH isocratic eluent method, the integration of peak areas, internal standard calibration with forced zero, linear calibration curves are shown to be the most accurate methods of quantitation. Check standards should be used to check the calibration accuracy. Calibration standard concentration effects were found to contribute to the less accurate quantification of oligosaccharides compared to monosaccharides, and correct concentration ranges are described. For gradient or isocratic IC-IPAD chromatographic runs, end-run washing with strong alkali eluent (for example, 200mM NaOH) was found to improve quantitation, and is necessary to remove strongly adsorbed anions. Five sugars were evaluated for their suitability as internal standards and both glucosamine and lactose were acceptable. Troubleshooting of problems that sometimes occur is discussed. Guidelines for improved quantitation of sugars are listed.