Ultra-trace determination of methyl carbamate and ethyl carbamate in local wines by GC-FID following preconcentration with C18-SPE

Abstract

An analytical method is described for ultra-trace determination of methyl carbamate and ethyl carbamate in locally produced fruit wines. The quantitative analysis involves with dichloromethane extraction followed by 30-fold preconcentration using C 18 SPE prior to measurement by capillary GC-FID. Under the optimized conditions, a good linearity of their calibration curves was obtained in the range of 0.1-50.0 mg/L with r 2 0.994. LOD and LOQ were 3.3-16.7 μg/L and 11.1-55.6 μg/L, respectively. The averaged recovery of these carbamates was ranged of 82.2-95.2% with RSD < 8.76%. The procedure was applied to determine both carbamate residues in various local wine samples. It was found that the concentration range of methyl carbamate (6.9-24.1 μg/L) was rather fluctuated and higher than that of ethyl carbamate (2.6-4.3 μg/L), suggesting that is a certain residual background contamination naturally occurring in the wine fermentation.