电感耦合等离子体质谱法测定大米粉中砷、铬、镉和铅元素的两种前处理方法比对研究

Comparative study of 2 kinds of pretreatment methods for determination of arsenic, chromium, cadmium and lead in rice flour by inductively coupled plasma mass spectrometry

中文关键词:  ICP-MS  湿消解法  大米粉  重金属元素

英文关键词:inductively coupled plasma mass spectrometry  microwave digestion method  wet digestion method  rice flour  harmful elements

中文摘要:

      目的 比对电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)检测大米粉中砷(As)、铬(Cr)、镉(Cd)和铅(Pb) 4种元素的两种前处理方法。方法 使用微波消解法和湿消解法对大米粉标准品进行前处理, 采用ICP-MS检测元素含量, 分别使用Z-比分数、标准值比较、平行偏差和加标回收率实验, 比较微波消解和湿消解法对元素含量测定结果的影响。结果 采用外标法建立的4种元素标准曲线的线性关系良好, 相关系数(r)>0.999。两种消解方法的|Z|均小于2, 平行偏差均小于5%[湿消解法(1.5 h, 120 ℃)]。使用湿消解法(1.5 h, 120 ℃)消解的大米粉中元素含量测定值更接近标准值。使用微波消解法的加标回收率分别为As 82.7%、Cr 95.9%、Cd 83.0%、Pb 101.4%, 而使用湿消解法(1.5 h, 120 ℃)的加标回收率分别为As 85.7%、Cr 99.0%、Cd 96.8%、Pb 112.8%, 湿消解法(1.5 h, 120 ℃)的加标回收率均高于微波消解法。结论 使用湿消解法(1.5 h, 120 ℃)作为前处理方法, 在检测大米粉中元素含量的准确性要优于微波消解法, 且具有简便、高效的特点。

英文摘要:

      Objective To compare 2 kinds of pretreatment methods of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of 4 kinds of elements (As, Cr, Cd and Pb) in rice flour. Methods Microwave digestion method and wet digestion method were used to pretreat the standard rice flour and the element content were detected by ICP-MS. The effect of two methods on element content determination were compared through Z-score method, comparing with standard values, parallelism error comparison and spiked recoveries experiments. Results The linear relationship between 4 kinds of element standard curves established using the external standard method was good, with a correlation coefficient (r)>0.999. The |Z| of both digestion methods were less than 2, and the parallel deviation was less than 5% [wet digestion method (1.5 h, 120 ℃)]. The measured value of element content in rice noodles digested by wet digestion method (1.5 h, 120 ℃) was closer to the standard value. The recovery rates of As using microwave digestion method were 82.7% Cr 95.9%, Cd 83.0%, Pb 101.4%, the recovery rates of As using wet digestion method (1.5 h, 120 ℃) were 85.7% Cr 99.0%, Cd 96.8%, Pb 112.8%, the spiked recovery rate of wet digestion method (1.5 h, 120 ℃) was higher than that of microwave digestion method. Conclusion The accuracy of element content determination in rice flour using the wet digestion method as the pretreatment method is better than that of microwave digestion method, and it has the characteristics of simplicity and efficiency.