Folin-Ciocalteu spectrophotometric assay of ascorbic acid in pharmaceutical tablets and orange juice with pH adjustment and pre-extraction of lanthanum(III)-flavonoid complexes

Olgun F. A. O., OZYURT D., BERKER K. I., DEMIRATA B., APAK R.

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, vol.94, no.12, pp.2401-2408, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 94 Issue: 12
  • Publication Date: 2014
  • Doi Number: 10.1002/jsfa.6569
  • Journal Name: JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2401-2408
  • Istanbul Technical University Affiliated: No

Abstract

BACKGROUND: This study proposes modifications to the conventional Folin-Ciocalteu (FC) spectrophotometric method for individually determining ascorbic acid (AA) in complex matrices in the presence of other phenolics and potential interferents. The conventional FC assay in the aqueous phase, which normally measures total water-soluble phenolics and other antioxidants, has recently been modified by incorporating isobutanol (iso-BuOH) in the solvent mixture for the simultaneous determination of lipophilic and hydrophilic antioxidants in foods.