Solid-Phase Spectrophotometric Determination of Mercury(II) Ions Using Diphenylcarbazone

A colorimetric sensor based on a transparent polymethacrylate matrix modified with diphenylcarbazone was developed with a view to spectrophotometric determination of Hg(II) in various objects. The effect of pH of a solution of diphenylcarbazone on its immobilization into a polymer matrix was studied. The maximum value of the analytical signal was reached near 520 nm and remained almost unchanged in the 3-11 pH range, as established. During the study of complexation of diphenylcarbazone immobilized into a matrix with mercury(II) ions, there were found optimum conditions for determination of Hg2+: pH 2.5-4 and duration of the interaction of mercury with diphenylcarbazone (with violet complex formation) of no more than 15 min. Mercury content was determined spectrophotometrically in the 1-25 mu g/dm(3) range by measuring absorption of light near 540 nm. The developed procedure of express analysis of mercury(II) was tested during studying organomercury granosan pesticide by indirect electrooxidation..