SPECTROPHOTOMETRIC DETERMINATION OF ASCORBIC-ACID USING AN IRON(II)-PYRIDINE-PICOLINIC ACID COMPLEX

An extractive spectrophotometric method for the determination of micro amounts of ascorbic acid has been developed by exploiting its reducin g nature. Iron(III) is converted to iron(II) by the addition of ascorb ic acid, which forms an extractable yellow-colored complex with picoli nic acid and pyridine. The absorbance is measured at 400 nm. Beer's la w is obeyed in the concentration range 0.4-5.6 mu g ml(-1). This metho d has been satisfactorily applied to the analysis of a variety of samp les, including pharmaceuticals, food products and biological fluids.