Determination of Ascorbic Acid in Pharmaceuticals and Biological Fluids by the Quenching of Europium Luminescence

Abstract

Here we present a novel strategy for the quantification of ascorbic acid (AA) (vitamin C). The developed method is based on the quenching effect produced by AA on the time-resolved luminescence signal of europium ions using excitation and emission wavelengths of 388 nm and 617 nm. The method presents a linear dynamic range from 0.2 to 2 µg mL−1 with a detection limit of 0.06 µg mL−1 and a relative standard deviation lower than 6%. The method was applied to the determination of AA in pharmaceutical preparations, human serum and human urine. The obtained results in pharmaceuticals were compared with a reference method; the recovery yields were close to 100% in all cases. The accuracy of the method was statistically assessed, demonstrating the suitability of this alternative method for the determination of AA in pharmaceuticals and biological samples, requiring no sample treatment except for a dilution step.