电感耦合等离子体质谱法测定锡粉基体的记忆效应研究

锡在质谱仪中的记忆效应较为严重,故消除锡粉基体效应是采用质谱法对锡粉中杂质元素进行测定的前提。采用王水加热溶解锡粉样品后,加入4 mL氢溴酸-盐酸混酸(V/V=1∶1),于110 ℃高温下挥发除锡约0.5 h,重复挥发过程共3次,以气溶胶稀释-电感耦合等离子体质谱法(ICP-MS)测定了样品中铅、铟、锰、锌的含量。实验表明:锡粉经过前处理后,样品溶液中锡的残留量均小于样品质量的0.04%;优化后的仪器参数为,载气流量0.60 L/min,稀释气流量0.42 L/min。将方法应用于锡粉实际样品中铅、铟、锰和锌的测定,相对标准偏差为3.6%～4.7%,回收率为89%～110%。选取一锡粉样品,分别按照实验方法和电感耦合等离子体原子发射光谱法对这4种元素进行测定,结果基本一致。

Study on memory effect of tin powder matrix by inductively coupled plasma mass spectrometry

The key to determination of impurity elements in tin powder was to eliminate the matrix effect of tin powder because of its serious memory effect in mass spectrometer. After the tin powder sample was dissolved with aqua regia by heating, 4 mL of hydrobromic acid-hydrochloric acid mixture (V/V=1∶1) was added, and tin was removed by volatilization at 110 ℃ for about 0.5 h. The volatilization process was repeated for three times in all. Then, the content of lead, indium, manganese and zinc in sample was determined by aerosol dilution-inductively coupled plasma mass spectrometry (ICP-MS). The results indicated that the amount of residual tin in sample solution was less than 0.04% of sample mass after the pretreatment of tin powder. The optimized instrumental parameters were listed as follows: carrier gas flow rate of 0.60 L/min, and dilution gas flow rate of 0.42 L/min. The proposed method was applied to the determination of lead, indium, manganese and zinc in actual tin powder sample. The relative standard deviations (RSD) were in range of 3.6%-4.7%, and the recoveries were between 89% and 110%. The contents of four elements above in one tin powder sample were determined by the experimental method and inductively coupled plasma atomic emission spectrometry, respectively, and the results were basically consistent.