H_2O_2氧化橙黄G和间甲酚紫褪色光度法测定痕量Co^(2+)

Catalytic Kinetic Spectrophotometric Determination of Trace Cobalt Based on Oxidation of Orange G and m-Cresol Purple by Hydrogen Peroxide

在NH3-NH4Cl缓冲溶液中,利用痕量Co2+对H2O2氧化橙黄G(OG)和间甲酚紫(m-CP)混合指示剂的褪色反应具有催化作用,通过测量500nm和575nm波长处催化和非催化体系吸光度的变化值,建立了双波长双指示剂催化动力学光度法测定痕量Co2+的新方法。该方法的线性范围为0.004~0.04μg/mL,检出限为3.0×10-5μg/mL,用于维生素B12针剂中痕量Co2+的测定,回收率为95.8%~102.8%。

A dual-wavelength dual-indicator catalytic kinetic spectrophotometric method for the determination of trace Co2＋was studied.This method was based on Co2＋catalyzing oxidation of orange G（OG）and m-cresol purple（m-CP）by hydrogen peroxide in NH3-NH4 Cl medium.The absorbances of the catalytic and noncatalytic systems were measured at 500 and 575 nm,respectively.Under the optimum conditions,the linear range of determination is 0.004-0.04μg/mL and the detection limit is3.0×10-5μg/mL.The method was applied for the determination of trace Co2＋in vitamin B12 injection sample and the recoveries were in the range of 95.8%-102.8%.