GC-ITMS determination and degradation of captan during winemaking.
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.
Dipartimento di Tossicologia, Università di Cagliari, via Ospedale 72, 09124 Cagliari, Italy.
Alberto
A
Angioni
Vincenzo L
VL
Garau
Ana
A
Aguilera Del Real
Marinella
M
Melis
Elizabeth V
EV
Minelli
Carlo
C
Tuberoso
Paolo
P
Cabras
D002215:Captan / Q000032:analysis* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D005511:Food Handling; D005638:Fruit / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D010797:Phthalimides / Q000032:analysis; D027843:Vitis / Q000737:chemistry; D014920:Wine / Q000032:analysis*
D010797:Phthalimides; C009417:tetrahydrophthalimide; D002215:Captan