新显色剂5-(4-溴苯偶氮)-8-羟基喹啉与钴(Ⅱ)显色反应的研究及应用

Study and Application of the Chromogenic Reaction of Co(II) with a New Chromogenic Reagent 5-(4-Bromo phenylazo)-8-Hydroxy1-Quinoline

研究了新显色剂 5 -(4-溴苯偶氮 ) -8-羟基喹啉 (BAHQ)与钴 (Ⅱ )形成配合物的条件。试验表明 ,该显色剂的离解常数pKa1 ,pKa2 分别为 1.80 ,7.90。BAHQ与钴 (Ⅱ )形成配合物的最大吸收峰在 483nm处。钴 (Ⅱ )浓度在 0～ 16 μg/ 2 5mL范围内符合比耳定律 ,表观摩尔吸光系数ε483 =5 .10× 10 4L·mol- 1 ·cm- 1 ,对比度△λ =88nm。考查了二十多种离子的干扰情况 ,用于测定维生素B1 2 药品中的钴 。

The conditions for the color reaction of Co(II) with the new chromogenic reagent 5\|(4\|Bromo\|Phenylazo)\|8\|Hydroxy1\|Quinoline(BAHQ) are studied.The pk\-\{a1\},pk\-\{a2\} of the chromogenic reagent are 1.80 and 7.90. A complex is formed from the reaction between Co(II) and BAHQ. The complex maximum absorption is at 483 nm,Beer's law is obeyed in the range of 0～16 μg/25 mL and the apparent molar absorption coefficient is 5.10×10\+4 L·mol\+\{-1\}·cm\+\{-1\}.The interference of more than twenty ions is investigated.This method is applied to determination of Co(Ⅱ) in vitamin B\-\{12\} with satisfactory results.