Thioglycolic Acid as an Amperometric Reagent for Trace Determination of Fe(III) and Fe(II) In Presence of Each Other

Amperometry is a very simple though one of the formost instrumental method of determining even trace level dilute solutions. It is an extended application of polarography. Amperometric determinations of Fe(II) and Fe(III) was carried out with the help of thioglycolic acid (TGA) at d.m.e. in 0.1M KCl medium. In this method, Fe(III) involves no chemical interaction and is based on the phenomenon of mutual compensation of cathodic current of metal species and anodic current of TGA, Fe(II) method seems to be the consequence of complexation reaction. Metal species TGA titrimetric ratio has been found to be 1:2 for Fe(II) and 1:1 for Fe(III). Solutions as dilute as 13.96 ppm [Fe(II)] and 5.58 ppm [Fe(III)] estimated with high degree of accuracy.

Amperometric determination of Fe(III) in the presence of Fe(II) was also carried out successfully and was found that the presence of 0.2M (NH₄)2SO₄ in the Fe(II) solution did not allow it to react with TGA. While an indirect method has been developed for estimating Fe(II) in presence of Fe(III). Tolerance limits for foreign ions have been worked out. This method also enabled the estimation of ferrous content in a drug of the brand name Fefol.