Spectrophotometric determination of periodate with salicylaldehyde guanylhydrazone. Indirect determination of some organic compounds using the Malaprade reaction

Abstract

Salicylaldehyde guanylhydrazone reacts with periodate in ammoniacal buffer (pH 9.2) to give a red colour. The reaction can be used for the spectrophotometric determination of trace amounts of periodate. The maximum molar absorptivity at 495 nm is 3.5 × 10³ l mol^–1 cm^–1 and Beer's law is obeyed between 10 and 45 p.p.m. of periodate with a relative standard deviation of 0.5%. The determination of periodate can be performed in the presence of a 50-fold (m/m) excess of iodate. The method was applied to the indirect determination of several organic compounds via the Malaprade reaction and good results were obtained.