甲烷动态反应-电感耦合等离子体质谱标准加入测定高纯钛中痕量铁

Determination of Trace Iron in High Purity Titanium by Methane Dynamic Reaction-Inductively Coupled Plasma Mass Spectrometry Standard Addition Method

建立了电感耦合等离子体质谱(ICP-MS)快速测定高纯钛中痕量铁的方法。采用氢氟酸和硝酸溶解高纯钛样品,稀释、定容后直接进入ICP-MS检测;采用标准加入法消除基体效应,避免了离子交换、热水解沉淀等去除基体复杂的样品处理方式;以甲烷(CH4)为反应气,在实际样品中优化确定了动态反应池的最佳工作条件,CH4流量为0.7 L/min,低截取质量参数(RPq)为0.55,高截取质量参数(RPa)为"0",有效消除了ArO+(m/z=56)对56Fe+的干扰。在确定的检测条件下,绘制了一高纯钛样品中的标准加入工作曲线,线性方程为y=2745.53x+1708.19,相关系数r2为0.9999,此曲线可转换为"外标法"的校准曲线,线性方程为y=2745.53x+136.19,其它样品可在此曲线下检测,无需再进行标准加入操作,不会降低检测效率;方法的检出限和测定下限分别为0.029和0.097μg/g,精密度(RSD,n=11)小于7%,回收率为97.5%~106.0%。对3个实际高纯钛样品中痕量铁进行了测定,含量分别为0.53、0.96和4.74μg/g,测定过程及结果均表明本方法适用于高纯钛中痕量铁的快速准确测定。

A method for rapid determination of trace iron in high purity titanium by inductively coupled plasma mass spectrometry(ICP-MS)was developed.The high purity titanium samples are dissolved by hydrofluoric acid and nitric acid and directly determined by ICP-MS after being diluted to a fixed volume.The matrix effect is eliminated by a standard addition method,which avoids ion exchange,thermal hydrolysis precipitation or other complicated sample treatment methods.Taking methane(CH4)as the reaction gas,the optimum working conditions of the dynamic reaction are optimized for the real sample.When the flow rate of CH4 is 0.7 L/min,the Rpq is 0.55 and the Rpa is"0",the interference of ArO+(m/z=56)to 56Fe+is effectively eliminated.The standard addition curve of a high purity titanium sample is drawn under the determined testing conditions.The linear equation is y=2745.53x+1708.19,and the correlation coefficient is 0.9999.The curve can be transformed into the calibration curve of"external standard method"and the linear equation is y=2745.53x+136.19.The iron content in other samples can be detected under this curve,no standard addition operation is needed in every sample,and the detection efficiency is not reduced.The detection limit and the quantification limit of method are 0.029 and 0.097μg/g,respectively,the precision(RSD,n=11)is less than 7%,and the recovery is 97.5%~106.0%.The trace iron in three samples of the high purity titanium is determined,the results are 0.53,0.96 and 4.74μg/g,respectively.The determination process and results show that the method is suitable for rapid and accurate determination of trace iron in high purity titanium.