Quantification ethyl carbamate in wines using reaction-assisted-extraction with 9-xanthydrol and detection by heart-cutting multidimensional gas chromatography-mass spectrometry.

9-Xanthydrol was introduced as an assisted-extraction-reagent to quantify ethyl carbamate (EC) in wines by heart-cutting multidimensional gas chromatography coupled with mass spectrometry (MDGC-MS). 9-Xanthydrol could help to increase the extraction efficiency, because it could react with ethyl carbamate to form the low-polar product, which facilitated the transfer of ethyl carbamate into organic phase. Then the reaction product was decomposed in high temperature, so ethyl carbamate could be obtained again in injector port. Heart-cutting multidimensional gas chromatography coupled with mass spectrometry was used not only for avoiding 9-xanthydrol interference but also for getting a larger volume injector, higher sensitivity and lower limit of detection. The method was optimized and validated in terms of sample volume, sodium chloride, the acid concentration, the 9-xanthydrol concentration and the reaction time. Good linear relationship (R = 0.9998) over the concentration range of 2.00 μg L - 200.00 μg L was obtained. The limit of detection (LOD, 0.02 μg L) and quantification (LOQ, 0.10 μg L) were lower than previously reported. The RSDs of precision (repeatability and reproducibility) were lower than 8.15%, and the recovery (96.17-99.25%) and accuracy (99.21-110.93%) were validated as well. This methodology was applied to the quantification of ethyl carbamate in several different fermented wines with values ranging from 13.05 to 155.20  μg L.