Assay of riboflavin in sample wines by capillary zone electrophoresis and laser-induced fluorescence detection

To routinely assay the concentration of riboflavin (RF) in wines, a rapid and sensitive method was developed and evaluated. The method is based on a simple sample preparation, capillary zone electrophoretic separation and laser-induced fluorescence detection (CZE-LIF). Sample preparation required only dilution and filtration. Under optimized conditions, the limit of detection of riboflavin was 0.5 micro g/L, using a hydrodynamic sample introduction of 10 s at 54 mbar. The method was fully validated: the recovery of RF in wines was >95%. The concentrations of RF within the three sample types of Italian wines investigated here ranged from 69 to 151 micro g/L with a mean value (+/-SD) of 112 +/- 25 micro g/L, from 74 to 193 micro g/L with a mean value of 115 +/- 45 micro g/L, and from 156 to 292 micro g/L with a mean value of 226 +/- 40 micro g/L, for white, rosé, and red wines, respectively. Such an accurate and highly sensitive CZE-LIF method represents a powerful improvement over previous methods in terms of sensitivity, simplicity, and efficiency. It is well suited to satisfy the demands for accurate and sensitive detection with minimal sample preparation and cleanup.