Chen Qian, Wu Xi, Hou Xian-deng, Xu Kai-lai
Guang Pu Xue Yu Guang Pu Fen Xi. 2015 Sep;35(9):2393-6.
Methyltin mercaptide is widely used as one of the best heat stabilizer in the polyvinylchloride (PVC) thermal processing due to its excellent stability, good transparency, high compatibility and weather resistance. The content of sulfur and tin significantly affects its quality and performance, so it is of great significance to develop an analytical method for the simultaneous determination of sulfur and tin. Inductively coupled plasma atomic emission spectrometry (ICP-OES) has been a powerful analytical tool for a myriad of complex samples owing to its advantages of the low detection limits, rapid and precise determinations over wide dynamic ranges, freedom from chemical inter-element interferences, the high sample throughput and above all, simultaneous multi-elements analysis. Microwave technique as a well-developed method for sample preparation can dramatically reduce the digestion time and the loss of volatile elements compared with the traditional open digestion. Hereby, a microwave-assisted acid digestion (MW-AAD) procedure followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis was developed for the simultaneous determination of Sn and S in methyltin mercaptide. This method has the advantages of simplicity, rapidness, good accuracy, green and less use of samples. Parameters affecting the MW-AAD such as the digestion solution and digestion time were optimized by using a chemical analyzed reference sample (DX-181) to attain tin and sulfur quantitative recoveries. HNO3-HCl-HClO4 (v/v/v=9:3:1) and 10 min were the optimum digestion solution and digestion time, respectively. Under optimum conditions, the standard addition method and the standard calibration curve method were both been used to detect Sn and S in DX-181. There was no significant difference between two methods and the relative deviations to the chemical analysis values were both less than 2%. Additionally, the accuracy of the MW-AAD method was examined by analyzing three methyltin mercaptide samples (DX-181, DX-990, DX-960). The results were satisfactory with the relative deviations (<3%) and the recoveries of standard addition (99%~102%).
巯基甲基锡因其优异的稳定性、良好的透明度、高相容性和耐候性，被广泛用作聚氯乙烯（PVC）热加工中最佳的热稳定剂之一。硫和锡的含量显著影响其质量和性能，因此开发一种同时测定硫和锡的分析方法具有重要意义。电感耦合等离子体原子发射光谱法（ICP-OES）由于具有检测限低、在宽动态范围内快速准确测定、不受化学元素间干扰、样品通量高以及最重要的是可同时进行多元素分析等优点，已成为分析众多复杂样品的强大工具。微波技术作为一种成熟的样品制备方法，与传统的开放式消解相比，可显著缩短消解时间并减少挥发性元素的损失。据此，建立了一种微波辅助酸消解（MW-AAD）程序，随后采用电感耦合等离子体发射光谱（ICP-OES）分析，用于同时测定巯基甲基锡中的锡和硫。该方法具有操作简单、快速、准确度高、绿色环保且样品用量少的优点。通过使用化学分析标准样品（DX-181）优化影响MW-AAD的参数，如消解溶液和消解时间，以实现锡和硫的定量回收。HNO3-HCl-HClO4（v/v/v=9:3:1）和10分钟分别为最佳消解溶液和消解时间。在最佳条件下，采用标准加入法和标准校准曲线法对DX-181中的锡和硫进行检测。两种方法之间无显著差异，与化学分析值的相对偏差均小于2%。此外，通过分析三个巯基甲基锡样品（DX-181、DX-990、DX-960）检验了MW-AAD方法的准确性。结果令人满意，相对偏差（<3%）和标准加入回收率（99%~102%）。
