【摘要】 本文报道了两种新显色剂3-溴-4-（4-硝基苯基重氮氨基）偶氮苯（BNDAB）和3-溴-4-（2-溴-4-硝基苯基重氮氨基）偶氮苯（BBNDAB）的合成,性质及其与Cd（Ⅱ）的显色反应。在弱碱性介质中,并有Triton X-100存在下两试剂均与Cd（Ⅱ）形成组成比为2:1的橙红色络合物。对BNDAB,λ_max^Cd-R=495nm,ε₄₉₅=1.56×10⁵L·mol^-1.cm^-1;对BBNDAB,λ_max^Cd-R=504nm,ε₅₀₄=1.50×10⁵L·mol^-1.cm^-11。镉量分别在0～8μg/25ml,0～10μg/2Sml范围遵守比耳定律。两试剂中BBNDAB有较好的选择性。用其测定环境水标样和锌合金中的镉含量,结果满意。更多还原

【Abstract】 Two new color reagents, 3-bromo-4-（ 4-nitrophenyldiazoamino ） azobenzene （BNDAB） and 3-bromo-4-（2-bromo-4-nitrophenyldiazoamino）azobenzene （BBNDAB）, were synthesized. In weakly alkaline medium and in the presence of Triton X-100, two reagents react with Cd to form orange-red complexes （2 : 1）. The molar absorptivity of BNDAB and BBNDAB was 1.56×10⁵ at 495 nm and 1. 50×10⁵ L ·mol_-1 ·cm_-1 at 504 nm, respectively. Beer’s law was obeyed in the range of 0-8 and 0-10 μg/25ml for BNDAB and BBNDAB, respectively. The selectivity of BBNDAB was better. It has been applied to the determination of trace Cd in standard water samples and zinc alloys with satisfactory results.更多还原