4,5-二溴邻硝基苯基荧光酮与镧(Ⅲ)显色反应研究与应用

Study on the Color Reaction of Lanthanum(Ⅲ) with 4,5-Di-bromo-2-nitro-phenylfuorone and Its Application

研究了在表面活性剂吐温-80存在下，镧（Ⅲ）与4，5-二溴邻硝基苯基荧光酮（DBONPF）的高灵敏显色反应，并建立了测定镧（Ⅲ）的新方法。实验发现，在PH=10.3NH4Cl-NH。缓冲溶液中，镧（Ⅲ）与4，5-二溴邻硝基苯基荧光酮形成紫色络合物，络合物的最大吸收波长为594．0nm，表观摩尔吸光系数ε=2．31×10^5L·mol^-1·cm^-1。镧（Ⅲ）的浓度在0～35μg／25mL的范围内符合比耳定律。本法用于铜合金试样中微量镧的测定，结果令人满意。

In the presence of surfactant tween-80, the photometric properties of color reaction of 4,5-Dibromo-2-nitro-phenylfuorone （DBONPF） with La（ Ⅲ ） were studied. Based on this fact, a new method was established for the determination of La（ Ⅲ）. The experimental results showed that La（ Ⅲ） reacted with DBONPF to form a micelle complex with a maximum absorption at 594.0 nm in a pH 10.3 NH4Cl- NH3 buffer solution. The apparent molar absorptivity of the complex was 2.31 × 10^5 L. mol^-1 . cm^-1. Beer＇s law was obeyed in the range of 0-35 μg La（Ⅲ） per 25 mL. The proposed method has been applied to the determination of trace amount of La（ Ⅲ ） in the copper alloy with satisfactory results.