超级微波消解-电感耦合等离子体质谱(ICP-MS)法测定石墨中的杂质元素

Determination of Impurity Elements in Graphite by Inductively Coupled Plasma Mass Spectrometry with Super-microwave Digestion

针对目前石墨的微波消解法存在用酸量大、酸体系复杂、处理时间长的问题,通过考察超级微波消解仪不同消解终点保持温度、消解酸体系及不同的保温时间,建立了电感耦合等离子体质谱(ICP-MS)法测定石墨中镁、铝、钾、钛、锰、铁、钴、镍、铜、锌、钼等11种杂质元素的分析方法。结果表明,在硝酸-高氯酸(1∶3)体系中,消解终点保持温度为260℃,保温时间为30 min,可将石墨完全消解,方法线性相关系数R^(2)均在0.999 5以上,方法检出限为0.001~0.19 mg/kg,方法定量限为0.004~0.62 mg/kg。通过合成样品法得到方法的加标回收率96.0%~118%,相对标准偏差0.60%~6.1%,可以满足石墨中多元素测定的需求。相较于传统石墨前处理方法,超级微波消解法具有用酸量少、酸体系简单、耗时短、安全性高、消解彻底等优点,可为各类石墨样品的多元素检测工作提供可靠的方法支撑。

In view of the problems of high acid consumption,complex acid system and long treatment time in the microwave digestion method currently used for digesting graphite,an analytical method for the determination of 11 impurity elements in graphite by inductively coupled plasma mass spectrometry(ICP-MS) was established by investigating the different end-point holding temperature,digestion acid system and holding time of super microwave digester.The results showed that in nitric acid-perchloric acid(1∶3) system,graphite could be completely digested by keeping the temperature at 260 ℃ for 30 min.The linear correlation coefficient R^(2) of the method was above 0.999 5,the detection limit was 0.001-0.19 mg/kg,and the quantitative limit was 0.004-0.62 mg/kg.The spiked recoveries was from 96.0% to 118%,and the precision was from 0.60% to 6.1%,which met the demand of multi-element determination in graphite.Compared with the traditional graphite pretreatment method,the super-microwave digestion method has many advantages,such as less acid amount,simple acid system,short time-consuming,high safety and thorough digestion,which can provide a reliable method for multi-element detection of various types of graphite samples.