An Automated Multicommuted Flow Analysis Procedure for Photometric Determination of Reducing Sugars in Wine Employing a Directly Heated Flow‑Batch Device

Marcos Brasil,Boaventura Reis

doi:10.21577/0103-5053.20170047

Abstract

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.

Highlights

Determination of reducing sugars in a variety of matrices is of great interest and has been accomplished by employing analytical procedures based on UV-Vis spectrophotometry,[2,3,5,6,7,9,10] infrared spectroscopy,[4] atomic absorption spectrometry,[8] potentiometry with ion-selective electrodes,[1] and biamperometry.[11]
The temperature sensor embed in the flow-batch device generates an electric potential difference that increases with temperature, presenting a linear relationship of 10 mV °C, which is stored in the control software running on the microcontroller device
A directly heated flow-batch device was employed for sample heating, as shown in Figure 1, which was machined from a stainless steel block

Summary

Introduction

Determination of reducing sugars in a variety of matrices is of great interest and has been accomplished by employing analytical procedures based on UV-Vis spectrophotometry,[2,3,5,6,7,9,10] infrared spectroscopy,[4] atomic absorption spectrometry,[8] potentiometry with ion-selective electrodes,[1] and biamperometry.[11]. UV-Vis spectrophotometry is by far the most commonly used technique for the determination of reducing sugars as it allows the implementation of analytical procedures using relatively simple equipment. Most reported spectrophotometric methods for determination of reducing

Methods

Results

Conclusion