GC-ITMS Determination and Degradation of Captan during Winemaking

• Published in: Journal of agricultural and food chemistry Vol. 51; no. 23; pp. 6761 - 6766
• Main Authors: Angioni, Alberto, Garau, Vincenzo L, Aguilera Del Real, Ana, Melis, Marinella, Minelli, Elizabeth V, Tuberoso, Carlo, Cabras, Paolo
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 05.11.2003
• Subjects: Biological and medical sciences; Captan - analysis; Captan - metabolism; Chromatography, High Pressure Liquid; Fermentation; Fermented food industries; Food Handling; Food industries; Fruit - chemistry; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Hydrogen-Ion Concentration; Phthalimides - analysis; Vitis - chemistry; Wine - analysis; Wines and vinegars; winemaking; Metabolite; Wine making; Pesticides; residues; Foodstuff; Grape must; Recovery; metabolites; Fungicide; Captan; Imide; Gas chromatography; Rapid technique; Toxicology; Phthalimide derivatives; Dicarboximide; Measurement method; tetrahydrophthalimide; Degradation product
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0342876

Captan and its metabolite tetrahydrophthalimide (THPI) were determined in grapes, must, and wine by GC-ITMS. Pesticides were extracted with acetone/petroleum ether (50:50 v/v). Because of the high selectivity of the ITMS detector, no interferent was found and cleanup was not necessary. Recoveries from fortified grapes, must, and wines ranged between 90 and 113% with a maximum coefficient of variation of 11%. Limits of quantitation were 0.01 mg/kg for both compounds. In model systems, captan and its metabolites, THPI, cis-4-cyclohexene-1,2-dicarboxylic acid, and 1,2,3,6-tetrahydrophthalamic acid, were determined by HPLC. The degradation of captan during winemaking was studied. Captan degraded in must, giving 100% THPI, and at the end of fermentation, only THPI was found in wine. The degradation of captan to THPI was due to the acidity in must and wine. This metabolite was present at low levels on grapes, and, unlike captan, it had no negative effect on the fermentative process. Model systems showed that the mechanism of disappearance of captan in grapes was due to photodegradation and codistillation. Keywords: Captan; tetrahydrophthalimide; metabolites; winemaking; residues