ICP-AES内标法测定铬系乙烯聚合催化剂中Cr、Ti、Mg、Al的含量

Determination of titanium, chromium, magnesium and aluminum in chromium-based ethylene polymerization catalysts by ICP-AES with internal standard method

关键词:  电感耦合等离子体发射光谱法  ICP-AES  微波消解  铬系乙烯聚合催化剂  基体效应 内标法 

Key words:  inductively coupled plasma atom emission spectrometry  ICP-AES  microwave digestion  chromium-based ethylene polymerization catalyst  matrix effect  internal standard method

摘要:

采用微波消解技术对铬系乙烯聚合催化剂进行了处理,制备样品水相测定溶液,对各元素分析谱线选择进行确定,对样品测定中产生的基体效应进行讨论,建立可靠的微波消解-等离子发射光谱法测定铬系乙烯聚合催化剂中Cr、Ti、Mg、Al含量的方法。溶液中Cr含量偏高,对Ti、Mg、Al的测定有显著的影响,加入混合内标溶液可以消除基体对待测元素的干扰。实验结果表明,各元素校准曲线线性相关系数均不小于0.999 8,检出限Cr为0.001 05 mg/L、Ti为0.001 35 mg/L、Mg为0.000 66 mg/L、Al为0.002 34 mg/L。按照该实验方法测定铬系聚乙烯催化剂样品中Cr、Ti、Mg和Al的含量,其结果的回收率为97.5%~104.0%,相对标准偏差(RSD,n=6)为0.51%~4.45%。 

Abstract:

The chromium-based ethylene polymerization catalyst was treated by microwave digestion, and aqueous sample solution was prepared. The selection of the analytical spectral lines for the measured elements was determined. The matrix effect in sample determination was discussed. The determination method of Cr, Ti, Mg and Al in chromium-based ethylene polymerization catalyst with microwave digestion technique and inductively coupled plasma atom emission spectrometry(ICP-AES)was established reliably. The high content of Cr element in solution had a significant effect on the determination of Ti, Mg and Al. Adding the mixed internal standard solution, the matrix interference to the measured elements was eliminated. According to the results, the linear correlation coefficient of the calibration curve of each element was not less than 0.999 8. The detection limits of Cr, Ti, Mg and Al were 0.001 05 mg/L, 0.001 35 mg/L, 0.000 66 mg/L and 0.002 34 mg/L, respectively. With this method, the recoveries were between 97.50% and 104.0%, and the relative standard deviations (RSD, n=6) were between 0.51% and 4.45%.