电感耦合等离子体质谱法测定Oleflex催化剂中铂

Oleflex工艺越来越受到关注,其所用Oleflex催化剂中的Pt含量对催化剂活性有较大影响,因此迫切需要一种高效稳定的检测Pt的方法。采用王水溶解样品,通过对绘制校准曲线用标准溶液系列进行Al基体匹配的方法消除基体效应,以¹⁹⁵Pt为测定同位素,建立了电感耦合等离子体质谱法(ICP-MS)测定Oleflex催化剂中Pt含量的方法。对等离子体气流量、测定介质进行了优化,确定等离子体气流量为10.5L/min,测定介质为2%HCl(V/V)。考察了基体Al对Pt测定的影响,结果表明,其负影响比较显著。用ICP-MS对样品溶液中的Al含量进行了测定,结果表明,无论称样量为0.1g还是0.2g,最终被溶解的Al₂O₃占催化剂的质量比均为19%左右。因此,实验选定称样量为0.1g,采用基体匹配法使得校准曲线用标准溶液系列中Al的质量浓度均为40μg/mL来消除基体效应。在选定的实验条件下测定Pt标准溶液系列,以Pt的质量浓度为横坐标,其对应的分析信号强度为纵坐标绘制校准曲线。方法的线性范围为0.001~2.00μg/mL,线性相关系数为0.9999,检出限为0.0004μg/mL。对新鲜Oleflex催化剂、再生Oleflex催化剂和废Oleflex催化剂样品按实验方法测定Pt含量,测定结果的相对标准偏差(RSD,n=5)为1.5%~2.8%,加标回收率为97%~104%。用实验方法与标准方法GB/T 23524—2009分别测定上述3种Oleflex催化剂样品中Pt,用t检验对测定结果进行验证。结果表明,两种方法测定样品中Pt含量的结果没有显著性差异。

Determination of platinum in Oleflex catalyst by inductively coupled plasma mass spectrometry

Oleflex process has been paid more and more attention. The platinum content in Oleflex catalyst has a great influence on the activity of catalyst. Therefore, it is necessary to develop a high-efficiency and stable method for the determination of platinum. The catalyst sample was dissolved with aqua regia. The standard solutions for the preparation of calibration curve were treated by the matching of Al matrix to eliminate the matrix effect. ¹⁹⁵Pt was selected as the isotope to establish the determination method of platinum in Oleflex catalyst by inductively coupled plasma mass spectrometry (ICP-MS). The carrier gas flow and determination medium were optimized: the carrier gas flow was 10.5L/min and the medium was 2% HCl (V/V). The effect of matrix Al on the determination of platinum was investigated. It was found that the negative effect was significant. The content of Al in the sample solution was determined by ICP-MS. The results showed that the mass ratio of dissolved Al₂O₃ in catalyst was about 19% regardless the sampling amount was 0.1g or 0.2g. Therefore, 0.1g of sample was used in experiments. The matrix matching method was adopted to make sure that the mass concentration of Al in standard solution series for calibration curve was all 40μg/mL, thus eliminating the matrix effect. The standard solution series of Pt were determined under the selected experimental conditions. The calibration curve was prepared using the mass concentration of Pt as the horizontal coordinate and the corresponding analysis signal intensity as the vertical coordinate. The linear range of method was 0.001-2.00μg/mL, the linear correlation coefficient was 0.9999, and the detection limit was 0.0004μg/mL. The content of platinum in fresh Oleflex catalyst, regenerated Oleflex catalyst and waste Oleflex catalyst samples were determined according to the experimental method. The relative standard deviations (RSD, n=5) of measured results ranged from 1.5% to 2.8%. The spiked recoveries were between 97% and 104%. The content of platinum in three catalysts above was determined by the experimental method and standard method GB/T 23524-2009, respectively. The determination results were verified by t test. The results showed that there was no significant difference between two methods for the determination of platinum content in catalyst samples.