PHOTOMETRIC-DETERMINATION OF DISSOLVED-OXYGEN WITH IRON(II) CACOTHELINE OXALATE BLUE

Iron (II)-cacotheline-oxalate blue solution is used as reductometric reagent for the estimation of dissolved oxygen. By titrating the blue complex solution photometrically, the dis-solved oxygen in water samples can be accurately determined in the range of 2 to 8 mg/l. The stoichiometry of the reaction between dissolved oxygen and the blue complex was found to be 1 : 0.8 or 5 : 4. The applicability of this method to distilled water, river water and reservoir water was tested. The Winkler's method [1] and its various modifications and adaptations, widely used for the determination of dissolved oxygen, are laborious and time consuming. Therefore a new method using iron (II)-cacotheline-oxalate (ICO) blue solution was developed for this purpose.