Identification and quantification of ethyl carbamate occurring in urea complexation processes commonly utilized for polyunsaturated fatty acid concentration

- Concentration of PUFA with urea depends on the fatty acid profile of the raw oil.
- Generation of ethyl carbamates can be increased at 70 °C than at 21 °C.
- Washing steps with water are able to remove the ethyl carbamates from the product.
- The procedure at 21 °C with 0.4 mL ethanol and 3 g urea can be optimal.

The concentration of polyunsaturated fatty acids by formation of urea adducts from three different sources was studied to elucidate the formation of ethyl carbamates in the course of these procedures. Two different methodologies were performed: with ethanol at high temperature and with hexane/ethanol mixtures at room temperature. It was proved that the amount of urethanes generated at high temperature was higher than at room temperature. Besides, subsequent washing steps of the PUFA fraction with water were efficient to remove the urethanes from the final products. The methodology at room temperature with 0.4 mL ethanol and 3 g urea provided good relationship between concentration and yield of the main bioactive PUFA, with the lowest formation of ethyl carbamates in the process.