Determination of maleic hydrazide residues in cured tobacco by gas chromatography.

A rapid and sensitive method for measuring maleic hydrazide (6-hydroxy-2H-pyridazin-3-one) residues in cured tobacco is described. A mixture of free and bound maleic hydrazide is extracted with hydrochloric acid in which maleic hydrazide glycoside is simultaneously hydrolysed. The free maleic hydrazide obtained is methylated using dimethyl sulphate and the derivative is partitioned into chloroform and determined by capillary gas chromatography using a nitrogen-phosphorus detector. The limit of detection of maleic hydrazide is 5 ppm.