This work presents an automated analytical procedure for the photometric determination of reducing sugars in wines. The procedure is based on the reaction of reducing sugars with potassium hexacyanoferrate(III) in an alkaline medium, and was implemented employing a multicommuted flow analysis (MCFA) approach. Sample heating to promote the reaction was accomplished using a flow-batch device, which was heated to 50 °C without the use of a fluid for heat exchange. The ability of the MCFA approach to handle small solution volumes was exploited in order to develop an analytical procedure that meets green analytical chemistry guidelines. After optimizing the operational variables, the analytical procedure afforded a linear response ranging from 0.75 to 6.00% (m/v) fructose (R(2) = 0.999), a limit of detection of 0.14% fructose (n = 11), a 3.5% relative standard deviation, reagent consumption and waste generation of 112 mg and 2.2 mL per determination, respectively, and an analytical throughput of 75 determinations per hour.
Keywords:
reducing sugar; multicommuted flow system; directly heated flow-batch device; green chemistry
