Flow chemosensing system for the spectrophotometric detection of sugars

A reverse FIA method for the determination of sucrose and fructose based on the reaction of 1,3 dihydroxibenzene with fructose and spectrophotometric detection is developed. The parameters of the FIA system and experimental c onditions of the reaction were studied and the advantages of the reverse mo de are presented. The analytical figures determined in flow were detection limit 3.02 mg L-1, repeatability (peak height) at the 40 mg L-1 sucrose lev el 1.84 % (n=10) and linear calibration up to 100 mg L-1 of sucrose. The se lective study showed that only galactose (at a molar ratio of 1:1.5) gave n egative deviations. The proposed method was applied to the analysis of sucr ose in condensed water of;he sugar industry and fructose in syrups. Recover y of sucrose using this method ranges from 93 to 103 % and results for fruc tose agreed with those obtained using another method. Preliminary results s howed the possibility for the prediction of sucrose and fructose concentrat ions using multivariate calibration.