Inside the bottle: fast analysis of amino acids in Italian wines by capillary electrophoresis with laser-induced fluorescence

Recent studies have shown the beneficial effects of reasonable amount of wine in the diet, probably due to its content of polyphenols, melatonin, serotonin, flavonoids, tannins and amino acids (AA). In particular, AA such as tryptophan, proline, arginine and alanine are important nutrients since they represent fundamental precursors in many physiological reactions. Moreover, it is known that the peculiar composition of AA in wine influence its bouquet (or flavor), since they are involved in the synthesis of volatile compounds. A fast analytical method has been developed for the determination of nine AA in wine. The method is based on capillary electrophoresis coupled to laser-induced fluorescence detection (CE-LIF). Separation was obtained by using a fused silica capillary and a background electrolyte composed of carbonate buffer, applying a 20 kV voltage. Direct hydrodynamic injection of samples was carried out after an original microwave assisted derivatisation step using 5-(4,6-dichlorotriazinyl)aminofluorescein (DTAF); the use of microwaves has the advantage of drastically reducing derivatisation times. The CE-LIF method has been validated in terms of precision and accuracy and successfully applied to some Italian wines of. Future method applications are planned to check for wine adulterations and commercial frauds.