胶束介质在速差动力学分析中的应用

本文主要报道溴化十六烷基三甲胺(CTMAB)表面活性剂在速差动力学分析中的应用,并用于高温合金试样中钼和钛的同时测定,在CTMAB存在下,3,5-二溴水杨基荧光酮(3,5-DBSF)与钼、钛形成三元配合物,其灵敏度比二元配合物分别提高了5.4和17.3倍,且由于胶束介质的存在,扩大了两组分形成配合物反应速率的差别,大大改善了方法的选择性。铝(III)、钙(II)、钴(II)、铬(III)、铜(II)、铁(II)、镁(II)、镍(II)等元素的允许量均在毫克级以上。钼的三元配合物形成速率较快,20秒内基本反应完全,钛的反应速率较慢,10分钟才达到平衡,基于两组分反应速率差别,采用对数外推法,经微机计算处理,进行了高温合金中钼、钛的同时测定,其相对偏差在5%以内。

The application of micellar media in rate differential kinetics analysis

The application of micellar media in rate differential kinetics analysis has been investigated. Molybdenum and Titanium in high temperature alloys were determinated. This method was based on the formation of ternary complex of them with 3, 5-dibromosalicylfluorone (3, 5-DBSF) and cetyltrimethylammonium bromide (CTMAB). In the medium of 0.4 mol.dm^-^3 HCl, the senstivity of ternary complex enhanced a ot with respect to the binary complex of 3, 5-DBSF without surfactant. In the meantime, the selectivity of reaction was improved obviously, because the difference of the rate of formation between titanium and molybdenum complex was increased. Al(III), Ca(II), Co(II), Cr(III), Cu(II), Fe(II), Mg(II) and Ni(II) did not interfere with the determination within the miligram region. The rate of the formation of ternary complex of Mo was very fast, but that of Ti was relatively slow. The relative deviation for determinations of two components was within 5%. The logarithmic extropolation method with microcomputer was used to calculate the contents of Mo and Ti in high temperature alloys.