Abstract

Investigation of charge transfer complex formation between Fe(III) and 2,6-dihydroxy benzoic acid and its applications for spectrophotometric determination of iron in aqueous media

Author(s): Mohammad Saeid Hosseini, Sara Madarshahian

On the basis of affinity of Fe(III) ions toward functional groups of 2,6- dihydroxy benzoic acid (2,6-DHB), a charge transfer complex (CT) is formed between Fe(III) ion and 2,6-DHB in acidic media. The stoichiometry and stability constant of the complex was determined using both mole ratio and Job’s methods. It was established a 1:1 complex was formed and the stability constant obtained fromboth themethod,mole ratio: 2.550.14105 and Job: 2.700.12105 is in agreement with together. This method was used for spectrophotometric determination of Fe(III) in aqueous media. The dynamic range and detection limit (DL) were 1.210-5 to 3.610-4M and 1.510-6M, respectively. The relative standard deviation (RSD) was found to be 0.76%in the replicate treatments (n=7) with 1.610-4MFe(III). The accuracy of the method was confirmed using a certified reference material (CRM) and it was applied satisfactorily for determination of iron in amultivitamin-multimineral tablet and variouswater samples.