SPECTROPHOTOMETRIC DETERMINATION OF ASCORBIC ACID USING 18-MOLYBDODIPHOSPHATE IN INTENSELY COLORED JUICES
- T. A. Denisenko
- Yu. V. Miekh
- A. B. Vishnikin
DOIAbstract
A simple, selective and highly sensitive method is proposed for spectrophotometric determination of ascorbic acid in juices, which have their own intense coloration with the use of a 18-molybdodiphosphate heteropoly complex (18-MPC). If the reaction is carried out at pH <5, unlike the methods with the Folin-Chiocalteu and CUPRAC reagents, there is no interfering effect of intensely colored anthocyanins, large concentrations of sulfites, polyphenols, reducing sugars, proteins and amino acids. The absorbance is measured at a wavelength of 910 nm, which corresponds to isobestic point in the spectra of one- and twoelectron heteropoly blues that co-exist in solutions by reduction of 18-MPC. At this analytical wavelength, overlapping with anthocy...
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