研究了新显色剂3-(6-溴苯并噻唑-2-偶氮)-2,6-二羟基苯甲酸(BTAB)与铁的显色反应及高纯石英砂中微量铁的测定。在pH=6.2的醋酸盐缓冲体系和溴代十六烷基吡啶溶液(CPB)存在下,BTAB与Fe(II)形成1:2的红色配合物,在566.0nm处有最大吸收,稳定常数为5.10×109,摩尔吸光系数为1.183×104L/(mol?cm),铁含量在0～2.54μg/mL内符合朗伯-比耳定律,建立了一种新的Fe(II)的测定方法。反应有很好的选择性。不经分离、掩蔽可直接测定高纯石英砂中微量铁。 The chromogenic reaction of iron (Ⅲ) with a new chromogenic reagent 3- (6-bromobenzothiazole-2-azo) -2,6-dihydroxybenzoic acid (BTAB) and the determination of trace iron in high purity quartz sand were studied. BTAB forms a 1: 2 red complex with Fe (II) in the presence of pH = 6.2 acetate buffer and brominated hexadecylpyridine (CPB) solution with maximum absorption at 566.0 nm. The stability constant Was 5.10 × 109, the molar extinction coefficient was 1.183 × 104L / (mol? Cm), and the iron content was within the range of 0 ~ 2.54μg / mL. This method established a new Fe (II) . The reaction is very selective. Without separation, masking can be directly measured in high purity quartz sand trace iron.