Determination of Free and Bound Maleic Hydrazide Residues in Tobacco by High Performance Liquid Chromatography

A new method is described for the qualitative and quantitative determination of both free and bound maleic hydrazide residues in tobacco leaves and cigarette filler by high performance liquid chromatography. Analyses were carried out by hydrolyzing samples of ground tobacco with 4 N hydrochloric acid for 40 minutes under reflux followed by sample chromatography, running isocratic elutions with a dilute solution of phosphoric acid. The quantitative determination of maleic hydrazide was performed by light absorption at 320 nm, by the calibration curve method. Recoveries of maleic hydrazide added to tobacco samples were greater than 90 %. The detection limit of the method, determined on ground tobacco leaves, was at least 5 ppm. The results obtained by this procedure and by the ISO standard method no. 4876 are in good accordance.