基于扫描电镜技术电弧直读原子发射光谱载体缓冲剂的改进

原子发射光谱粉末固体进样法由于样品处理方法简单,检出限低,环境污染小,被大量应用于痕量Ag、B、Sn等多种元素的同时测定,但显著的基体效应制约了方法的适用性。本文基于扫描电镜微区检测技术,对比分析了特定配方与不同样品、在不同时段反应产物的组成差异,结合蒸发曲线反推反应过程,研制了适用于不同基体类型地球化学样品的载体缓冲剂。在实现前人致力改善弧烧过程的基础上,研制的载体缓冲剂是以K2S2O7、Na F作为助熔剂,"催化"基体分解,与聚四氟乙烯、沉降S等协同促进待测元素以多种形式快速蒸发;缓冲剂在与样品基体作用过程中形成的Al_2O_3-SiO_2-CaO-BaO互熔体降低了Tammann温度,能够原位吸收Ca O、Si O等基体氧化物,抑制了其干扰。相比已有方法,灵敏度提高1.2倍以上,精密度、准确度、检出限等优于各类地球化学调查规范要求。

Improved Carrier Buffer for AC Arc Direct Reading Atomic Emission Spectrometry Based on the SEM Technique

Powder solid sampling atomic emission spectrometry is a simple sample pretreatment method with high sensitivity, low detection limit, and little environmental pollution. This method has been applied to the simultaneous analysis of trace Ag, B and Sn in geochemical samples. However, the serious matrix effect limits the application of this method. Based on the Scanning Electron Microscopy (SEM) technique, the differences in the composition of the reaction products at different times for specific formulations and different samples was compared. Combined with the evaporation curve to reverse the reaction process, a carrier buffer suitable for different types of geochemical samples was developed. In order to realize the improvement of the arc burning process, K₂S₂O₇ and NaF were used as flux during preparing carrier buffer to catalytically decompose the matrix. Synergizing with PTFE and sedimentation S promotes rapid evaporation of analyzed elements in various forms. The formation of Al₂O₃-SiO₂-CaO-BaO mutual melt lowers the Tammann temperature and can absorb matrix oxides in-situ, suppressing the interferences. Compared with the available method, the sensitivity increased by 1.2 times, and the precision, accuracy and detection limit are superior to a number of geochemical survey specifications.