双波长双指示剂催化光度法测定痕量铬

Dual-wavelength dual-indicator catalytic spectrophotometric determination of trace chromium

目的:建立用双波长双指示剂催化动力学光度法测定痕量铬(Ⅵ)的新方法。方法:在HAc-NaAc缓冲溶液介质中,利用铬(Ⅵ)催化过氧化氢氧化罗丹明B和苯酚红的指示反应,分别在430 nm和550 nm处测量催化体系和非催化体系吸光度的变化,用双波长双指示剂催化光度法测定痕量铬(Ⅵ)。结果:测定痕量铬(Ⅵ)的线性范围为0.010～3.30μg/25 ml,检出限为3.2×10-10g/ml。结论:该法简单,灵敏度高,选择性好,可用于水中痕量铬(Ⅵ)的测定。

Objective：To establish a new dual-wavelength and dual-indicator catalytic kinetic spectrophotometric method for the determination of trace amount of chromium（Ⅵ）.Methods：Chromium（Ⅵ） was determined by dual-wavelength and dual-indicator catalytic kinetic spectrophotometric method which was based on the chromium（Ⅵ） catalyzed oxidation of rhodamine B and phenol red by hydrogen peroxide in the HAc-NaAc buffer solution.The absorbance of the catalytic and uncatalytic systems were measured at 430 nm and 550 nm.Results：The linear range of determination was 0.010～3.30 μg/25 ml.The detection limit was 3.2×10-10 g/ml.Conclusion：The method is simple and of high sensitivity and good selectivity.It can be applied to the determination of chromium in water.