阴离子交换离子色谱法间接测定食品馅料中的二氧化硫脲

Indirect determination of thiourea dioxide in food fillings by anion-exchange chromatography

目的建立食品馅料中二氧化硫脲的离子色谱快速检测方法。方法基于二氧化硫脲在碱性无氧条件下可快速完全分解生成亚硫酸根的反应原理，在氩气饱和的KOH水溶液中反应并超声提取，使馅料中的二氧化硫脲完全转化为亚硫酸根，该提取溶液离心后经RP柱去除脂溶性杂质，经阴离子交换色谱柱IonPacASll-HC（4mmol／L×250mmol／L，5μm）分离，抑制型电导检测器分析，通过检测亚硫酸钠含量间接测定二氧化硫脲含量。结果在1．26-252mg／L范围内目标物线性关系良好（r≥0．9987），检出限（LOD）不高于6mg／kg，定量下限（LOQ）不高于12mg／kg，3个加标水平的方法回收率为92．3％-102．6％，相对标准偏差（RSD）为2．9％～4．9％。结论本方法快速、准确、重现性好，适用于食品馅料中二氧化硫脲的快速分析。

Objective To establish a method for the determination of thiourea dioxide in fillings of food by anion - exchange chromatography. Methods Based on the reaction that thiourea dioxides can rapidly and completely decompose in alkaline and anaerobic conditions, food fillings was treated with potassium hydroxide solution saturated with argon ultrasonic extrac- tion. And the formed sulfite was extracted with RP column from the resulted solution. The chromatographic separation was performed on an IonPacAGll -HC column （4 mmol/L×50 mmol/L, 5 μm）. Sulfite was detected by a suppressed con- ductivity detector. Results The calibration curve of sulfite was linear in the range of 1.26 - 252 mg/L with good regres- sion coefficient （ r ≥ 0. 998 7 ）. The limit of detection （ LOD, S/N ≥ 3 ） was not more than 6 mg/kg and the limits of quantita- tion （LOQ, S/N≥10） was not more than 12 mg/kg. The average recoveries ranged from 92. 3% to 102. 6%, with the rel- ative standard deviations （ESD） in the range of 2.9% - 4.9%. Conclusion The proposed method is rapid, accurate and suitable for the determination of thiourea dioxide in food fillings.