Highly Sensitive Method for Urea Detection in Wine

Trace amounts of urea (less than 50 μg/L) in wine were accurately determined using a modified high performance liquid chromatography (HPLC-fluorometric) technique. Appropriate selection of eluent, HPLC columns, and chiral derivatives for the o-phthalaldehyde solution provided a 20-fold enhancement of sensitivity over established methods. A linear relationship was observed at concentrations from 0.5–500 μg/L of aqueous urea solution. The threshold level for detectability of urea in wine was 5 μg/L. The method is simple enough to be applicable to most beverages.