Spectrophotometric determination of formaldehyde

A new spectrophotometric method for the determination of micro amounts of formaldehyde in aqueous and methanol solutions is based on the oxidation of formaldehyde by hydrous silver oxide at pH 11-12.5 and oxidation of the metallic silver produced, with iron(III) in the presence of Ferrozine. The absorbance of the resulting iron(II)-Ferrozine complex at 562 nm is proportional to the amount of formaldehyde and corresponds to an apparent molar absorptivity of 5.58 x 10(4) 1.mole(-1).cm(-1).