Iron(III) oxidized nucleophilic coupling of catechol with o-tolidine/p-toluidine followed by 1,10-phenanthroline as new and sensitivity improved spectrophotometric methods for iron present in chemicals, pharmaceutical, edible green leaves, nuts and lake w

► New and sensitivity improved spectrophotometric methods for iron. ► Determine iron of chemicals, pharmaceuticals, leaves, nuts and water samples. ► A nucleophile from iron(III) and catechol couple with o-tolidine/p-toluidine. ► Coupled products with iron(II) and 1,10-phenanthroline improve sensitivity.