吖啶红高灵敏催化荧光光度法测定痕量钴(Ⅱ)

在H2SO4介质中,KIO3可氧化吖啶红使之褪色并伴随着吖啶红荧光强度的减弱,但其反应速率较慢。当加入痕量钴(Ⅱ)时,氧化反应明显加快,体系荧光猝灭程度加强,钴(Ⅱ)对该氧化反应具有显著的催化作用。据此建立了一种灵敏度高、选择性好的测定痕量钴(Ⅱ)的催化荧光分析新方法,并研究了该方法的动力学条件。反应体系的激发波长和发射波长分别为530和550nm,催化体系可允许较大量的多种常见离子同时存在。测定钴(Ⅱ)的线性范围为0.3～4.8μg/L,检出限为2.5×10-11g/mL。方法可用于茶叶、人发和面粉等实际样品中痕量钴(Ⅱ)的测定。

Highly sensitive catalysis-fluorescence determination of trace cobalt(Ⅱ) based on the oxidation of acridine red by potassium iodinate

Acridine red can be oxidized by potassium iodinate in dilute sulfuric acid medium with discoloring and fluorescence quenching, but the reaction rate is very low. The presence of trace cobalt(Ⅱ) can accelerate the reaction rate apparently and make the net fluorescence value of the system decrease greatly, which indicates that the trace cobalt(Ⅱ) play a role as a catalyst in this reaction remarkably. Based on the investigation above, a highly sensitive and selective catalysis-fluorescence determination method of trace cobalt(Ⅱ) has been originally proposed. The wave-length of excitation is 530 nm and the wave-length of emission is 550 nm. The method permits the existence of more than 20 common foreign ions. The linear range of concentration of cobalt is 0.3～4.8 μg/L and the limit of detection is 2.5×10~(-11)g/mL. This method has been used for the determination of trace cobalt in tea, hair and wheat flour samples with satisfactory results.