能量色散X射线荧光光谱法对食品接触用紫砂制品中的钡元素测定研究

Determination of Barium in Purple Clay Products for Food Contact by Energy Dispersive X-Ray Fluorescence Spectrometry

为促使食品接触紫砂制品中添加剂的使用符合国家标准,通过仪器分析法,建立一种有毒钡盐添加于紫砂制品中的无损检测技术,使行业能有效利用于紫砂生产质量管理及产品材料的安全评估。以能量色散X射线荧光光谱法直接对样品进行测试,建立一套具有成分的标样以完成光子数与含量的函数关系,并对大量的紫砂原矿、泥料原料及各时期的紫砂制品进行对比数据库的建立以及精密度的分析。在所选择的仪器及工作条件下分析重复测试的一致性相对标准偏差RSD为1.75%~4.83%。标准样品的均匀性相对标准偏差RSD为3.10%~5.59%;选取10件紫砂器样品进行样品的均匀性分析,相对标准偏差RSD为1.23%~12.30%。对厚度由1.9~14.1 mm的试片进行检测,试验值与真实值的变化率为-6.94%~78.44%。对109件紫砂矿料样本进行分析,试验结果钡元素含量平均值为0.0295%。对三款原矿无添加碳酸钡的泥料原料以及两款添加约千分之三碳酸钡的紫砂泥料进行试验,结果显示有添加碳酸钡的泥料,钡的试验值为0.380%~0.398%。无添加碳酸钡的泥料,钡的试验值为0.0162%~0.0461%。对11件具有明确纪年的紫砂器进行试验,1979年及其之后样品的钡含量为0.2388%~0.3877%。从1085件紫砂成品样品实际分析数据中显示,1979年以后的紫砂制品中的钡含量呈现逐步攀升的趋势。该方法具有无破坏性、效率高、速度快、准确度及重复测试一致性好及操作简易等特点,相较于化学检验法更适合运用于食品接触陶瓷制品紫砂中添加剂碳酸钡的测定。同时,经过大量的试验数据得到人为添加碳酸钡的大致起始年代约在1979年,此后紫砂制品中钡元素的含量呈现不断上升的趋势,表明在缺乏有效测定方法和技术监管的情况下,当下添加碳酸钡的行为未能获得实质控制。

The purpose of this paper is to promote the use of additives in purple clay products for food contact in line with national standards.Through instrumental analysis,this paper has established a non-destructive testing method for toxic barium salt added purple clay products,so that the industry can effectively use this technology for purple clay production quality management and material safety assessment.The method is to directly test the samples by energy dispersive X-ray fluorescence spectrometry,establish a set of standard samples with components to complete the function relationship between photon number and content,and carry out a database of comparison and the precision analysis by a large number of purple clay raw ore,mud raw material and purple clay products in various periods.The process is to analyze the consistency of repeated tests under the selected instruments and operating conditions with RSD in 1.75%~4.83%.The relative standard deviations(RSD)of homogeneity of standard samples are 3.10%~5.59%.The relative standard deviations of 10 purple clay samples are 1.23%~12.30%.The test of the specimens with thickness ranging from 1.9 to 14.1 mm shows the change rate between the test value and the real value is-6.94%to 78.44%.The average content of barium in 109 samples of purple clay ore is 0.0295%.Tests are carried out on three kinds of clay materials without barium carbonate and two kinds of purple clay materials with barium carbonate of about 3‰and the results show mud materials with barium carbonate,and the test value of barium is 0.380%~0.398%.In the mud without barium carbonate,the test value of barium is 0.0162%to 0.0461%.The barium content of 11 purple clay ware samples from 1979 and later is 0.2388%to 0.3877%.The actual analysis data of 1085 purple clay samples show that barium content in purple clay products increased gradually after 1979.The conclusion is that this method has the characteristics of non-destructive,high efficiency,high speed,high accuracy,good consistency of repeated tests and easy operation,and it is more suitable for the determination of barium carbonate additive in food contact violet purple sand compared with the chemical test method.At the same time,through a large number of experimental data,it is found that the beginning of the artificial addition of barium carbonate was about 1979.Since then,the content of barium element in purple clay products has shown a rising trend,indicating that in the absence of effective measurement methods and technical supervision,the behavior of adding barium carbonate could not be substantially controlled.