The present study consists in a comparative evaluation of the L-ascorbic acid (AA) concentration from some commercial Romanian juices and wines. The samples was analyzed by high-performance liquid chromatography (HPLC) on an Alltima C(18) column with isocratic elution of methanol and water with formic acid (pH 3) (65:35, v/v) at a flow rate of 0.3 mL/min, a column temperature of 26°C, and UV detection at 243 nm. The amperometric measurements were carried out under magnetic stirring using 0.1 M phosphate buffer solution as supporting electrolyte and pH 7 with a new biosensor, consisting in ascorbate oxidase (AOx) and bovine serum albumine immobilization on the membrane of an oxygen electrode, followed by cross-linking with glutaraldehyde (GA). Our study showed that the biosensor works well in synthetic samples of AA and may be recommended for testing in real samples (wine and fruit juices).