双波长双指示剂催化动力学光度法测定痕量Fe(Ⅲ)

Dual-Wavelength Dual-Indicator Catalytic Kinetic Spectrophotometry for Determination of Trace Fe(Ⅲ)

研究了在HCl介质中,Fe（Ⅲ）催化H2O2氧化甲基橙和亚甲基蓝褪色的指示反应。通过测量510nm和660nm波长处催化和非催化体系吸光度的变化,基于Fe（Ⅲ）的浓度与两波长处吸光度差值的加和呈线性关系,建立了双波长双指示剂催化动力学光度法测定Fe（Ⅲ）含量的新方法。方法的线性范围为0.008-0.24μg/mL,用该法测定菠菜、紫菜、蛋黄中Fe（Ⅲ）含量,相对标准偏差为1.0%-4.6%,加标回收率为98.9%-104.6%。

The oxidization fading of methy1 ene blue and methyl orange catalyzed by trace iron in HC1 medium was studied.And,a new dual-wave1 ength and dual-indicator catalytic kinetic spectrophotometric method was established for the determination of trace iron.The absorbance of catalytic and non-catalytic systems was measured at 510 nm and 660 nm,respectively.The concentration of Fe（Ⅲ）showed linear relationship with the difference between absorbance at two wavelengths.The linear range of method was0.008-0.24μg/mL.The method could be applied to the determination of trace Fe（Ⅲ）in samples（such as spinach,laver and yolk）without pre-separation,giving the relative standard deviations of 1.0%-4.6% and the recoveries of 98.9%-104.6%.