ED-XRF法快速测定食盐中碘元素的实用性分析

Applicability Analysis of Iodine Elemental in Salt by Rapid ED-XRF Test Method

碘元素是合成甲状腺激素的重要元素,其摄入量的多少直接影响人体的健康。为了保证食用盐碘含量的合理性,碘元素的添加量已成为食盐企业生产控制的重点,因此碘元素的快速分析对生产企业提出了新的要求。文章介绍一种能量散射X射线荧光光谱(ED-XRF)快速测试方法:对食盐进行简单预处理(研磨、过筛),用XRF光谱仪建立食盐中碘元素含量和强度的校正工作曲线,然后测定未知食盐样品中的碘元素。该方法具有较低的检出限(LOD)和定量限(LOQ),检出限为0.67 mg/kg,定量限为1.54 mg/kg,完全满足食盐中碘元素的限量标准18 mg/kg^33 mg/kg的测量要求;测量定量限以上的含碘食盐样品时,其准确性与化学分析结果相当、测量结果的重复性等性能测试结果完全符合GB/T 4889-2008数据的统计处理标准。该方法预处理时间不超过4 min,完成一个样品的检测时间不超过6 min,该方法在食用盐生产企业中的加碘量监控上,有非常广阔的应用前景。

Iodine is an important element in the synthesis of thyroid hormones,and its intake directly affects the health of the human body.In order to ensure the rationality of consumption of salt-containing iodine,the addition of iodine has become the focus of production control in edible salt enterprises,and a new requirement for rapid testing of iodine elemental in salt has been put forward.A rapid Energy Dispersive X-ray Fluorescence Spectrometer(ED-XRF)test method is introduced in this article.One sample pretreatment method of salt is used,such as grinding and sieving.A calibration curve for the content and intensity of iodine in salt is established by XRF spectrometer,and then the iodine elemental in unknown salt is determined.This method has a low limit of detection(LOD),Limit of Quantity(LOQ),the LOD an LOQ of this method are 0.67 mg/kg,1.54 mg/kg respectively.And the LOQ of iodine elemental in salt can meet the national limit of iodine elemental in salt standard 18 mg/kg^33 mg/kg.When measuring the sample containing iodine salt above the LOQ,the accuracy of the test results is comparable to the results of the chemical analysis,and the repeatability of the test results is in full compliance with the standard statistical treatment of date of GB/T 4889-2008.The pretreatment time of the method is no more than 4 min,and the test time of samples is no more than 6 min.This method has a very broad application prospect in the monitoring of iodine addition in edible salt production enterprises.