酰氯化分离-电感耦合等离子体质谱法测定高纯铬中的痕量杂质元素

建立了酰氯化分离-电感耦合等离子体质谱法(ICP-MS)测定高纯铬中的12种痕量杂质元素的新方法。利用基体酰氯化生成酰氯铬具有低沸点的特性分离基体,有效克服了基体对待测元素的干扰和对仪器进样系统的污染。研究了温度和酸的加入量对分离效果的影响;测定不同基体~(50) Cr残留下~(50) V(R=0.25%)和~(50) Ti(R=5.18%)的值;在2h内酰氯化温度为130℃,酸的加入量为12mL时,可以实现基体99.99%分离;基体对~(50) V和~(50) Ti的干扰可以完全消除;与电感耦合等离子体发射光谱直接溶样法(ICP-OES),全谱直读型直流电弧原子发射光谱法(DC-Arc-AES)的对照实验表明本方法准确可靠;在选定的实验条件下,方法检出限(3σ)介于0.000 01%~0.000 06%,相对标准偏差(RSD)为1.7%~5.8%,加标回收率为90%~104%。本方法简单实用,能够满足纯度为4N(99.99%)的高纯铬中12种杂质元素的测定。

Chloroformylation-Separation of Matrix and Determination of Trace Impurities in High Purity Chromium by ICP-MS

A new method was developed for the determination of twelve different trace impurities in high purity chromium by ICP-MS after chloroformylation separation.The interferences on analytes and the pollution of sample introduction system were efficiently avoided by separation impurity elements from matrix chromium which makes use of chromyl chloride'low boiling point.The influences of temperature and dosage of acid separation effects were studied.The content of 50 V and 50 Ti changing with the amount of residual chromium in sample solution was determined.The analytical results proved to be accurate and valida-ted by comparing the proposed method with ICP-OES and AES with D.C electric as the excitation.Under optimized conditions, over 99.99% of the matrix chromium was removed by chloroformylation separation at 130 ℃ with the acid addition of 12 mL for 2 h,which eliminated the matrix effect and spectra interference in the following ICP-MS detection.It showed that the detection limit of the method was 0.00001%~0.00006%;the RSD was 1.7%~5.8%;and the recovery of standard addition was 90%~104%.The method is simple,applicative and suitable for the determination of impurities in high purity chromium of 99.99%.