Extraction and quantification of SO₂ content in wines using a hollow fiber contactor

Abstract

This research demonstrates how the sulfite content can be measured by cyclic voltammetry using a previously reported membrane absorber system, which separates efficiently sulfite present in wine. Results obtained show notably similar values to those obtained for the same wine samples using modified Monier-Williams method (aspiration method) and Ripper method. The membrane absorber system allows the release of the free SO 2, and can be used to determine the sulfur dioxide present in juices and other foods that contain high concentrations of phenols, polyphenols and other structurally related compounds that act as interferers in the electrochemical oxidation of sulfite. The absorber solution allows a direct measurement without change in pH or added electrolyte, facilitating the determination of great amounts of samples from diverse wines using only one calibration curve. In this way, a system that allows the detection of sulfite and that can be used in vineyards is obtained. Finally, the method was assessed on linearity, sensitivity, accuracy, reproducibility and repeatability, obtaining values that account for the applicability of the method.

Electrochemical Method for Sulfite Determination in Wines by Electrochemical Response Using a Membrane Absorber System

“…This study demonstrates that sulfite content can be measured by cyclic voltammetry enhanced by a membrane absorber system described in a previous work 6,7 . Membrane absorber efficiently separates the sulfite contained in wine and avoids the presence of other compounds, which can interfere these measurements.…”

Membrane Gas Absorption Processes: Applications, Design and Perspectives

“…Thus, a compact design can be proposed, and the gas phase is confined into the membrane pores as an effective supported gas membrane. This system has been studied for the removal of NH 3 from wastewaters and aqueous streams [40], the extraction of SO 2 during the sulfite quantification in wines [41] and the elimination of HCN from pharmaceutical wastewaters [42], plating waters or its recovery from cyanidation solutions in the mining industry [11,43]. Figure 4 summarizes the treated and receiving streams in each one of these applications as well as the circulation configuration used in the abovementioned studies.…”

“…Figure 4. Outline of the input and output streams in GFMA processes for (a) NH 3 removal from wastewater [40], (b) absorption of SO 2 from wine samples [41] and (c) HCN recovery from cyanidation solutions [11].…”

“…The GFMA process has been applied to extract or recover solutes of interest, such as ammonia from wastewater [40,46], SO 2 from wine [41,47] and HCN from different wastewaters [11], [42,48,49]. These studies have shown high recoveries of volatile solutes (>90%), producing a concentrate product in the absorption solution.…”

“…On the other hand, the well-known specific surface area into the membrane modules may enhance some procedures and processes at laboratory scale that need high reproducibility, such as analytical techniques [41] or the preparation of specific materials [50].…”