间溴偶氮羧-m与钡的显色反应研究

Reaction Between Barium and 3-(3-Bromophenylazo)-6-(3-carboxylphenylazo)chromotropic Acid and Its Analytical Applications

研究了显色剂间溴偶氮羧-m与钡的显色反应,探讨了配合物形成的条件及酸度、温度和表面活性剂等对反应的影响. 在pH值为4.0的乙酸-乙酸钠缓冲溶液中,Ba2+与显色剂在 l =670nm 处形成蓝色稳定配合物e=2.2 ×105Lmol-1 cm-1 ,络合物组成比为M:R=1:2 . 在0-11 ug /25ml范围内符合比耳定律. 用于土壤及白薯样品分析,效果良好.

A new type reaction between Barium and 3-(3-Bromphenylazo)-6-(3-carboxylphenylazo) chromotroic Acid is described .The suitable condition forming complex and the influence of acid media , temperature and surfactants on the complex formation reaction are examined .In HAc NaAc buffer solution(PH2.4), the two form a blue coordination compound , M:R=1:2 and absorption maxima at 670nm ,The apparent molar absoptivity is found to be 2.2 ×105 L·mol-1cm-1 ,over the concentration range of 0-1.1ug of Ba(Ⅱ) per twenty five milliliter solution is coincided with Beer抯 law.The method has been applied to the determination of Ba(Ⅱ) in soil and sweet potato .