微乳液增敏邻硝基苯基荧光酮光度法测定食品中痕量铅

Spectrophotometric Determination Trace Amount of Lead with o-Nitrophenylfluorone in Microemulsion after Sulfhydryl Dextrane Gel Preconcentration and Separation

本文研究了在微乳液介质中,pH=10.0时,铅与邻硝基苯基荧光酮(o NPF)显色生成稳定的1∶3配合物,在598nm处摩尔吸光系数为8.74×104L·mol-1·cm-1,铅含量在0～1.2μg/mL范围内符合比耳定律。采用巯基葡聚糖凝胶分离富集,消除了共存离子的干扰。用所拟方法测定食品中的微量铅,结果令人满意。

In this paper, the color reaction of lead with o-nitrophenylfluorone (o-NPF) in microemulsion has been studied. Lead (II) reacts with o-NPF to form a stable 1∶3 complex at pH 10.0. Its apparent molar absorptivity is 8.74×10~4 L·mol^(-1)·cm^(-1) at 598 nm. Beer's law is obeyed in the range of 0～(1.2 μg/mL). In order to improve the selectivity and sensitivity of the developed system in real sample analysis, sulfhydryl dextrane gel (SDG) separation/preconcentration prior to spectrophotometric analysis was employed. The method is used to determine trace amount of lead in food samples with satisfactory results.