The application of iron(III) complexlng with different forms of DNA for the development of the biosensor for blood serum assay

Abstract

Fe(III) complexing with DNA was studied using spectrophotometric and voltamperometric data and mathematic simulation as well. The binding constant for the hypothetical complex Fe(III)-DNA 1:1 was 1.4×10-3 mol-1·1. Fe(III) complexes with various forms of DNA were characterized in terms of their composition and binding constants. The complex composition for the immobilized denatured DNA (d-IDNA) was found to be 1:2.25 (nucleotide:Fe(III)); this complex was characterized by the highest value of binding constant. d-IDNA was included into an amperometric biosensor for assay of Fe(III) content in human blood serum. The method of Fe(III) selective determination in the form of the complexonate was elaborated with the lower limit of detection of 1×107 mol·l-1. The linear region of Fe(III) detection was within the following concentration range 1.0×10-7 - 6.0×10-5 mol·l-1. Determination of Fe(III) in the presence of matrix blood serum ions such as Mg(II), Zn(II), Cu(II) and Al(III) was carried out. The proposed method is well reproducible, characterised with an easy sampling and speed.