A new spectrophotometric method is proposed for the determination of saccharin sodium. The present method is based on solvent extraction into nitrobenzene of the ionpair formed between tris (1, 10-phenanthroline)-iron (II) and the anion of saccharin. The maximum absorbance of the extract in the organic phase is at 516 mμ. To obtain optimum conditions for the determination of saccharin sodium, various factors were investigated, A maximum extraction is obtained at pH 4-8, when an excess of at least 20-fold (molar) of the phenanthroline-iron (II) chelate to saccharin is present. The color intensity of the extracted species remains constant at room temperature for several hours after separation of the organic layer. A linear relationship is obtained over the tested range of 10-6 to 3.2 × 10-5M of saccharin in aqueous solution. The effect of several other food additives on this method was investigated. Saccharose, glucose, dulcin, citric acid, and sodium chloride do not interfere with the determination in a moderate amount. Sodium cyclamate gives a slight positive error.
