间接离子色谱法测定花茶中二氧化硫含量的研究.

【Objective】 To provide a method reference for the analysis and determination standards of sulfur dioxide in herb tea, a test method of sulfur dioxide by ion chromatography was established. 【Method】 Samples of herb tea were distilled under acidic conditions, and the sulfur dioxide produced was absorbed into hydrogen peroxide solution, and then was oxidized into sulfate ion. The solution was filtered with 0.22μm filtering menbrane, and the filtrate was separated on AG11-HC protective column and AS11-HC separation column. Chromatographic conditions of the eluent concentration and flow rate were optimized with ion chromatography-conductance detection mode. 【Result】 The optimum chromatographic condition was using 30.00 mmol·L-1 KOH as the eluent at a flow rate of 1.00 m L·min-1.Under this condition, sulfate standard curve correlation was good in the range from 3.60 mg·L-1 to 36.00 mg·L-1（r = 0.9998）, the detection limit of the method was 0.06 mg·L-1. Values of recovery rate were in the range of 80.89%-93.61%, and values of RSD’s（ n = 3） were found in the range of 2.45%-4.85%. 【Conclusion】 The indirect method by ion chromatography is simple and sensitive, which is suitable for the determination of sulfur dioxide in herb tea. [ABSTRACT FROM AUTHOR]