微波消解样品-电感耦合等离子体质谱法测定高纯金属硅中痕量硼

Determination of Trace Amount of B in High Purity Si by ICP-MS Using Microwave Assisted Dissolution

提出了用电感耦合等离子体质谱法(ICP-MS)测定高纯硅中痕量硼。高纯硅样品在密闭消解罐中用硝酸及氢氟酸混合酸进行微波加热消解,所得溶液用于ICP-MS测定其中的硼量,对基体和质谱干扰做了试验。质谱测定中选用铍作为内标以补偿信号漂移和基体效应,对样品的微波消解参数及测定时仪器的工作条件做了系统试验,并选定了优化的条件,所选用硼的同位素11B和12B均不受其它同量异位素及多原子离子等的质谱重叠干扰。对方法的回收率及精密度做了试验,所得结果为11B的回收率在98%～110%之间,12B的回收率在96%～107%之间,相对标准偏差(n=8)则依次为2.9%和2.8%,测得方法的检出限为4 ng·L-1(11B)和8 ng·L-1(12B)。

A method of ICP-MS for determination of trace amount of boron in high-purity silicon was proposed. Sample of high-purity silicon was digested with mixture of HNO3 and HF in the Mars-5 Microwave digestion system. The solution obtained was used for ICP-MS analysis. Matrix and MS interferences, working condition of the mass spectrograph and working parameter of the microwave digestion system were studied thoroughly and optimized. Beryllium was used as internal standard to compensate for the matrix and MS interferences. The isotopes, 11^B and 12^B were chosen as the analytical isotopes, since no mass spectrometric overlapping interferences due to co-existing isomers and muhi-atomic ions were observed with these 2 isomers. Tests for recovery and precision of the method were performed, and results obtained were as follows： values of recovery and RSD＇s （n=8） found were in the ranges of 98%-110% （for 11^B）, 96%-107% （for 12^B） and 2.9% （for 11^B）, 2. 8% （for 12^B） respectively. Values of detection limit found were 4 ng ·L^-1 （for 11^B） and 8 ng· L^-1 （for 12^B）.