面粉中溴酸钾的气相色谱测定

DETERMINATION OF POTASSIUM BROMATE IN FLOURS BY GAS CHROMATOGRAPHY

建立了面粉中溴酸钾的气相色谱测定方法。以Waters OASIS MAX阴离子交换固相萃取小柱对样品溶液进行净化,洗脱的溴酸根离子和溴离子在酸性条件下反应生成溴,而溴在酸性介质中与丁酮反应,生成溴丁酮,以气相色谱法分离,以电子捕获检测器检测其含量。通过对提取柱、溴化钾浓度、硫酸浓度、丁酮用量和反应时间等条件的优化,确立了最佳的测定参数。该方法的线性范围为1 mg/kg^20 mg/kg,标准曲线的相关系数为0.9988,回收率在94.0%~103.3%之间,平均回收率为97.9%,方法的精密度高(RSD在1.7%~4.0%),可作为一种新方法应用于面粉中溴酸钾的测定。

A gas chromatographic method for the determination of potassium bromate in flours has been established. Sample was refined by Waters OASIS MAX Extraction Cartridges, the eluted bromate ion reacts with bromide ion in an acidic medium, the produced bromine could reacts with butanone in the same acidic medium and produced bromobutanone, which can be separated by chromatograph and detected by ECD. The best conditions for the determination were optimized, including extraction column, concentration of potassium bromide and sulfuric acid, dosage of butanone, time of reaction and so on. The method proved to be reproducible(RSD=1.7%-4.0%),the calibration curve was linear in the range of 1-20 mg/kg,the coefficient of determination(R^2) was 0.9988,the recoveries ranged from 94.0%-103.5% with an average value of 97.9%.The new method could be used for the determination of potassium bromate in flours.