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N. Turkmen, F. Sari and Y. S. Velioglu, “Effects of Extraction Solvents on Concentration and Antioxidant Activity of Black and Black Mate Tea Polyphenols Determined by Ferrous Tartrate and Folin-Ciocalteu Methods,” Food Chemistry, Vol. 99, No. 4, 2006, pp. 835-841. doi:10.1016/j.foodchem.2005.08.034.

has been cited by the following article:

• TITLE: Investigation of a Simple and Cheap Source of a Natural Indicator for Acid-Base Titration: Effects of System Conditions on Natural Indicators

  AUTHORS: Daniel A. Abugri, Ohene B. Apea, Gregory Pritchett

  KEYWORDS: Waakye Leaves; Ethanol; Natural Indicator; Acid-Base Titration; Dyes

  JOURNAL NAME: Green and Sustainable Chemistry, Vol.2 No.3, August 20, 2012

  ABSTRACT: This study investigated a natural indicator for acid-base titration which is extracted from guinea corn leaves popularly called “waakye leaves” in Ghana. Four types of acid-base titration were studied: strong acid versus (v/s) strong base, strong acid versus weak base, weak acid versus strong base, and weak acid versus weak base. The indicator color change, pH range and the average titre values were determined for each type of acid-base titration. These values were comparable to those obtained from three standard indicators: methyl orange, methyl red and phenolphthalein. Total flavonoids (TF) and condensed tannin (CT) from the crude leaves extract were determined which might be the major reasons for the activity of the extract as an indicator for simple acid-base titration. The authors suggest that the natural indicator is cheap, available, simple to extract, user and environmentally friendly and could be an excellent replacement for standard indicators.