SCREENING AND DEVELOPMENT OF HERBAL ACID-BASE pH INDICATOR FROM TRADITIONAL FLOWERS

Indicators used in titrations show well-marked changes of color in certain intervals of pH. Most of these indicators are organic dyes and are of synthetic origins. But due to environmental pollution, availability and cost, the search for natural compounds as an acid-base indicator was started. The present vocation highlights the exploit of the ethanolic extract of Calendula officinalis and Butea monosperma flowers as an acid-base indicator in acid-base titrations. This natural indicator is easy to extract as well as easily available. Promising results were obtained when it was tested against standard synthetic indicators. Titration shows sharp color change at the equivalence point. The equivalence points obtained by the flowers extract coincide with the equivalence points obtained by standard indicators. The rationale behind using these natural indicators in preference to synthetic indicators is its easy availability, inertness, ease of preparation and cost effectiveness.