【摘要】 研究了4-(2-吡啶偶氮)间苯二酚与铂(Ⅳ)的显色反应,建立了一个测定铂的光度分析新方法。在pH5.0的醋酸-醋酸钠缓冲介质中,溴化十六烷基三甲基铵(CTMAB)存在下,4-(2-吡啶偶氮)间苯二酚与铂(Ⅳ)反应生成摩尔比为2∶1稳定络合物,该络合物可用阳离子交换树脂固相萃取柱富集,吸附柱上富集的络合物用乙醇洗脱后用分光光度法测定。分离后的测定液中,络合物最大吸收波长为490nm,表观摩尔吸光系数ε=1.22×105L·mol-1·cm-1,铂(Ⅳ)含量在0～1.6μg/mL内符合比尔定律,相关系数r=0.9978,对30余种共存离子进行试验,结果表明,大多数常见离子不干扰测定。方法用于合金、矿石、粉煤灰等样品中铂的分析,相对标准偏差小于5.1%,加标回收率在96%～105%之间。更多还原

【Abstract】 A new spectrophotometric method was developed for the determination of trace platinum based on the rapid reaction of platinum (Ⅳ) with 4-(2-pyridylazo)resorcin. In the presence of CTMAB and HAc-NaAc buffer solution (pH 5.0), 4-(2-pyridylazo)resorcin reacted with platinum (Ⅳ) to form a stable (2∶1) complex. The colored complex could be extracted by cation exchange resin cartridge and eluted from cartridge with ethanol before being determined by spectrophotometry. Its apparent molar absorptive coefficient ε was 1.22 ×105 L·mol-1·cm-1 at 490 nm. Beer’s law was obeyed in range of 0-1.6 μg/mL for Pt(Ⅳ), and r = 0.997 8. More than 30 categories of co-existing ions didn’t interfere with the determination of platinum. This method has been applied to the determination of platinum in samples with the RSD smaller than 5.1 % and the recovery of 96 %-105 %.更多还原