离子色谱-梯度淋洗柱后衍生紫外检测法测定面制品中溴酸盐

Determination of Bromate in Flour Prducts by Gradient Ion Chromatography with Postcolumn Deriviation and UV Detection

研究离子色谱柱后衍生紫外检测法快速测定面制品中溴酸盐含量。采用IonPac AS19分析柱(250 mm×4 mm),IonPac AG19保护柱(50 mm×4 mm),KOH梯度淋洗,柱温30℃。以0.26 mol/L KI为衍生试剂,2.0mmol/L(NH4)6Mo7O24.4H2O为催化剂,检测波长352 nm。样品用纯水萃取,经高速离心20 min(转速10 000 r/min),过C18预处理小柱,用0.45μm膜过滤后直接进样。试验结果表明,在0.01～1.0 mg/L范围,方法相关系数为0.9996,加标平均回收率85.0%～101.4%,检出限0.004 mg/L。该方法操作简单方便,灵敏选择性高,适用于常规样品分析。

An ion chromatography method with post-column reaction and UV detection for the determination of bromate has been developed and validated in flour products.The target separation was performed on the guard column IonPac AG19（50 mm×4 mm） and analytical column IonPac AS19（250 mm×4 mm） using KOH as an eluent with a self-regeneration suppressor.The postcolumn deriviation solution was 0.26 mol/L KI containing a catalyst of 2.0 mmol/L（NH4） 6Mo7O24.4H2O,a detection limit for bromate of 0.004 mg/L was generated.Calibration curve produced excellent regression（r2=0.9996） in the range from 0.01～1.0 mg/L.The real samples was extracted by ultrasonic bath by ultra water and then centrifuged for 20 min at 10 000 r/min.The supernatant filtered through C18 cleanup column and a 0.45 μm membrane filter was injected directly to IC system.Experimental results showed that the recovery obtained in the accuracy test for all flour products studied were in the 85.0%～101.4% range and the intraday precisions was smaller than 0.68%.It can be easily and conveniently adopted for the routine quality control analysis.