【摘要】 本文系统探讨了聚乙烯醇（PVA-124）存在下,铬（Ⅲ）-溴邻苯三酚红（BPR）-乙基紫（EV）体系产生的协同显色反应。在pH4.8～5.5 HAc-NaAc缓冲介质中,Cr（Ⅲ）-BPR-EV形成[EV]^-·[Cr（BPR）]型离子缔合物,λ_max=535 nm,ε_535nm=1.1×10⁵L·mol^-1·mol^<sub>-1·Cm^-1,铬（Ⅲ）含量在0～7μg/25ml范围内吸光度遵从比尔定律,反应选择性好,用于污水中铬的测定得满意结果。根据络合物组成探讨了反应机理。更多还原

【Abstract】 Chromium( Ⅲ ) ion can form a colour ion-associate complex with both bromopyrogallol red (BPR)and ethyl violet (EV) in a HAc-NaAc medium (pH 5. 0). The composition of the complex was found to be Cr: BPR : EV = 1 : 1 : 1 with the apparent molar absorptivity of 1. 1 × 105 L · mol-1cm-1. Beer’s law is obeyedover the range of 0-7 μg/mi for chromium. This method has been applied to the determination of chromiumin water with good precision and accuracy.更多还原