Trace Determination of Iron(ID) by a Kinetic Method Based on Catalase like Activity of [(trien)Fe( OH)2]+ Complex on Decomposition Rate of Hydrogen Peroxide

Abstract

A sensitive kinetic method is developed for the trace determination of Fe(III). The method is based on the catalase- like catalytic activity of [(trien)Fe( OH)₂]⁺ (trien=triethylenetetraamine) complex on the decomposition rate of hydrogen peroxide at <em>p</em>H = 10.0 &plusmn; 0.02 and temp. = 25 &plusmn; 0.1ᵒC. At moderately high concentration of hydrogen peroxide, the initial rate is linearly related to [catalyst]. A fixed-time procedure is used to obtain a linear calibration curve between the initial rate and [catalyst] in the ferric ion concentration range of 1.0 x 10^-8 to 4.9 x 10^-6 mol dm^-3. The detection limit is 1 x 10^-8 mol dm^-3 and maximum percentage error is 12.5 in the lower limit. The method is sensitive, accurate, inexpensive and rapid. The interferences from a large number of cations with the exception of Mn²⁺ are negligible.