Abstract: The naphthalene phase spectrophotometer was used to determinate the micro aluminum in polypropylene resin samples with Chrome azurol S(CAS) as chromatogenic agent. Then the experimental conditions were carefully investigated by adding masking agent CyDTA-Mn with masked ions. The results indicate that when CAS, emulsifier OP, CTMBA and buffer solution, Al(Ⅲ) react with CAS, the complex compound form, which has maximum absorption wavelength at 680 nm. The reaction finished instantly, then kept 8.5 h. Under the optimum conditions, the linearity range of Al is 0～9.3 μg, the linearity coefficient is 0.999 2 and the apparent molar absorption coefficient is 8.98×104 L/(mol•cm). The polypropylene resin was analyzed. The average recovery rate of the artificial synthetic sample is 96.94%, the average recovery rate is 89.32%～102.70%, and the analytical result RSD is 2.63% .

Key words: Naphthalene phase spectrophotometer, Chrome azurol S, Aluminum, Polypropylene resin

摘要： 以铬天青S（CAS）为显色剂，采用萘相分光光度法测定聚丙烯树脂中的铝。通过加入掩蔽剂环己二胺四乙酸(CyDTA－Mn)掩蔽干扰离子。详细考察了测定条件。结果表明，在CAS、聚乙二醇辛基苯基醚（OP）、溴化十六烷基三甲基溶液（CTMAB）以及乙二胺-盐酸缓冲溶液存在下，铝与显色剂形成络合物，铝络合物的最大波长为680 nm，反应瞬时完成并保持8.5 h。在适合条件下，铝的线性范围为0～9.3 μg。线性相关系数为 0.999 2,摩尔吸光系数为8.98×104 L/(mol•cm)。人工合成样的平均回收率为96.94%。对实际聚丙烯树脂分析，相对标准偏差为2.63%，加标回收率为89.32%～102.70%。

关键词: 萘相分光光度法, 铬天青S, 铝, 聚丙烯树脂