微波消解-ICP-MS测定富硒大米中5种微量元素和5种重金属元素

Determination of 5 trace elements and 5 heavy metal elements in selenium-rich rice by microwave digestion-ICP-MS

建立电感耦合等离子体质谱法(ICP-MS)同时测定富硒大米中5种微量元素和5种重金属元素的方法 ,研究市售富硒大米中10种元素的含量。分别对硝酸用量、过氧化氢用量、微波消解程序进行优化,得出优化前处理方法,并用质控样品进行验证。结果表明:优化的前处理条件为:7 mL硝酸,20℃升温5 min、恒温5 min,160℃升温5 min、恒温5 min,180℃升温5 min、恒温15min。该方法简单快速、试剂用量少,准确性好,适用于富硒大米中多元素的同时测定;用该方法测定市场上随机购买的富硒大米,硒元素含量参差不齐,与其他4种微量元素(Zn、Fe、Co、Mo)没有明显的正相关或负相关关系,5种重金属(Pb、As、Hg、Cd、Cr)均在限量范围内。

The method for determination of five trace elements and five heavy metals in selenium-rich rice was set up by inductively coupled plasma mass spectrometry (ICP-MS), and the content of ten elements in selenium-rich rice from the market was studied. The optimum pretreatment method was obtained by optimizing the amount of nitric acid, the amount of hydrogen peroxide and the microwave digestion procedure, and the quality control sample was used to verification. The results showed that the optimal pretreatment conditions of the method were: 7 mL nitric acid, heating up time to 20 ℃ was 5min and constant temperature for 5 min, heating up time to 120 ℃ was 5min and constant temperature for 5min, heating up time to 180 ℃ was 5 min and constant temperature for 15 min. The method was simple and fast, with a little reagent and good accuracy. It was suitable for simultaneous determination of many elements in selenium-rich rice;the selenium contents of selenium-rich rice which purchased randomly from the market were different. There was no obvious positive or negative correlation with the other four trace elements (Zn, Fe, Co, Mo). The five heavy metals (Pb, As, Hg, Cd, Cr) were within the limits.