COMPETITION OF TWO ESSENTIAL METALS (Fe an‎d Cr) FOR COMPLEXATION WITH DTPA

DTPA formed stable complex with Cr(III) and Fe(III). Both the two metals are essential nutrient for biological system. DTPA introduced in the body for heavy metals detoxication, where it may interact with essential metals also.In this regard effect of concentration of added metal, pH and temperature on the exchange of metal fromits DTPA complex was studied. Fe(III)DTPA is very strong complex, Cr(III) is unable to replace Fe(III)from its DTPA complex. Increase in concentration of added metal and ligand has negligible effect. Therise of temperature from 30 to 60°C has also small effect on the trend.At pH 4.0, Cr(III)can replace a maximum of 30% Fe(III) from the Fe(III)-DTPA complex. Whereas pH7.0 increased the stability of Fe(III)-DTPA complex and only a small amount of Fe(III) can be replaced.