Fluorimetric determination of total ascorbic acid by a stopped-flow mixing technique.


A simple, rapid and automatic fluorimetric method for the determination of total ascorbic acid is described. The method makes use of the stopped-flow mixing technique in order to achieve the rapid oxidation of ascorbic acid by dissolved oxygen to dehydroascorbic acid, which then reacts with o-phenylenediamine to form a fluorescent quinoxaline. The initial rate and fluorescence signal of this system are directly proportional to the ascorbic acid concentration. The calibration graph was linear over the range 0.1-30 microg ml(-1) (kinetic method) and 0.25-34 microg ml(-1) (equilibrium method). The precision (% RSD) was close to 0.5%. The method has been used for the determination of ascorbic acid in pharmaceutical formulations, fruit juices, soft drinks and blood serum.

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@article{PrezRuiz2001FluorimetricDO, title={Fluorimetric determination of total ascorbic acid by a stopped-flow mixing technique.}, author={Tom{\'a}s P{\'e}rez-Ruiz and Carmen Mart{\'i}nez-Lozano and Virginia Tom{\'a}s and Jos{\'e} Fenoll}, journal={The Analyst}, year={2001}, volume={126 8}, pages={1436-9} }