Continuous-flow determination of reducing sugars and sucrose in natural and industrial products with periodate oxidation and a periodate-sensitive flow-through electrode

Abstract

A continuous-flow method for the determination of mixtures of reducing sugars and sucrose in natural and industrial products is described. The sample, before and after hydrolysis of sucrose, reacts with an excess of periodate in a flow system and the decrease in periodate activity is monitored with a periodate-sensitive flow-through electrode. The recorded peak heights are indirectly linearly related to the concentration of reducing sugars in the range 3–18 mM. The sucrose concentration is calculated by difference. The analysis is completely automated, requires no sample pre-treatment except for the hydrolysis of sucrose and samples can be analysed at a rate of 30 per hour with a relative error and a relative standard deviation of 1–3%. Comparison with Fehling's method for various natural and industrial products gave satisfactory results.