表面活性剂的应用研究——动力学光度法测定痕量硒碲

Application Research on Surfactant—— Kinetic Spectrophotometric Determination of Trace Selenium and Tellurium

研究了表面活性剂在Se和Te诱导反应中的作用 ,对反应机理进行了初步探讨。实验表明 ,在选定条件下 ,加入适量非离子表面活性剂Tween-80 ,使Te的诱导反应速度加快 ,灵敏度提高 1倍 ,并利用其对Se有抑制反应速度的作用 ,使Te对Se的抗干扰能力增强。阴离子表面活性剂十二烷基苯磺酸钠对Se和Te均有加速反应的作用 ,Se的灵敏度提高 1 .3倍 ;Te的灵敏度提高40 %。基于此 ,所建立的方法可用于地质样品中纳克级Se和Te的测定。测定Te的线性范围 0 .0 1～ 0 .4μg/L ,相对标准偏差 (n =5) 5.6 % ;测定Se的线性范围 0 .1～ 2 μg/L ,相对标准偏差 (n =5)7.5%。经 4种地质标样分析验证 ,结果与标准值相符。

s: Effects of some surfactants on inductive reactions of Se and Te were studied and the reaction mechanism was discussed preliminarily in this paper. The results from the experiments show that by adding moderate amount of surfactant of Tween-80 the inductive reaction of Te can be speeded up with improvement of spectrophotometric sensitivity for Te by a factor of 2. The suppression effect of Tween-80 on the inductive reaction of Se reduces significantly the interference from Se on Te. The addition of anion surfactant of dodecylbenzene sulfonic acid sodium salt (SDBS) also speed up the inductive reaction for both Te and Se, which improves the spectrophotometric sensitivities by factors of 2.3 for Se and 1.4 for Te. These two systems can be used for spectrophotometric determination of trace Se and Te. The dynamic linearity ranges are 0.01～0.4 μg/L for Te with precision of 5.6% RSD ( n =5) and 0.1～2 μg/L for Se with precision of 7.5% RSD ( n =5). The methods have been verified by the determination of trace Te and Se in 4 geological standard reference materials. The results are in agreement with certified values.