Development of vapor generation combined with potentiometric detection for determination of sulfite in beverages.

摘要

This paper describes a simple, sensitive and cost effective method developed for determination of sulfite in beverages. The procedure is based on chemical vapor generation of hydrogen sulfide, collection of the vapor in an alkaline solution, and then potentiometric determination of the sulfide using a commercial sulfide selective electrode. The influential parameters on analytical performance such as concentration of reagents, flow rate of carrier gas, reaction temperature and gas collection time are evaluated and discussed. In the optimum conditions, the method was linear in the range of 2-25 mug mL-1 of sulfite with a detection limit of 0.7 mug mL-1. The relative standard deviation of the method was 1.2 % for five replicate experiments at 10 mug mL-1 concentration level. The method was successfully applied for determination of sulfite in different beverages with the relative recoveries between 92.2 and 96.2 %. The proposed method can be applied for quality control and consumer safety in food and beverages industrial plants