密闭溶样-电感耦合等离子体质谱法测定煅烧高岭土中微量重金属元素

Determination of Trace Heavy Metal Elements in Caclined Kaoline by Inductively Coupled Plasma-Mass Spectrometry with Pressurized Acid Digestion

建立了密闭溶样-电感耦合等离子体质谱法同时测定煅烧高岭土中铜、铅、锌、铬、镉和锰等6个微量重金属元素的有效方法。实验中对仪器的最佳工作参数进行了优化，选择适当的同位素，并用铑作内标元素，有效地抑制了分析信号的漂移以及分子和多原子离子的质谱干扰；探讨了混合酸消解体系、消解液用量、密闭溶样的时间对测定结果的影响。以硝酸-氢氟酸作为消化试剂，在180℃下溶解4h能完全消解样品。在选定的实验条件下，对煅烧高岭土样品进行了精密度和回收率试验，方法相对标准偏差（RSD，n=9）为0．96％～2．22％．加标回收率为98．0％～101．5％。

A method for the determination of copper, lead, zinc, chromium, cadmium and manganese in calcined kaoline samples by inductively coupled plasma-mass spectrometry （ICP-MS） with pressurized acid digestion was developed. The ICP-MS instrument operating parameters were optimized. The mass spectral interferences were eliminated by selecting 65Cu, 208Ph, 66Zn, 52Cr, 114Cd and 55Mn as analytical isotopes. And Rh was selected as internal standard to compensate the analytical signal drift. The factors affecting the analytical results such as selection of sample digestion system, dosage of the digestion solvents and digestion time were studied. Under the optimized condition with HNO3-HF digestion system at 180 ℃ for 4 h, the recovery for these elements was 98.0% - 101.5% with precision of 0.96% - 2. 22% RSD （ n = 9 ）. The proposed method has been applied to the determination of these trace heavy metal elements in calcined kaoline samples with satisfactory results.