EVALUATION OF YELLOW ASOKA (IXORA COCCINEA L.) FLOWER ETHANOL EXTRACT AS A NATURAL ACID–BASE INDICATOR
DOI:
https://doi.cibangsa.org/DOI-2026-342Keywords:
Yellow Asoka, natural acid–base indicator, pH response, acid–base titration, ethanol extractAbstract
Natural acid–base indicators derived from flowers offer a potential alternative to synthetic indicators, but their performance depends strongly on extraction solvent and pH response. This study evaluated Yellow Asoka (Ixora coccinea L.) flower extracts prepared with 96% ethanol and ethyl acetate for pH-dependent color behavior and application in acid–base titration. The extracts were examined across buffer solutions from pH 1–13, and the ethanol extract was subsequently tested in strong acid–strong base, weak acid–strong base, and strong acid–weak base titration systems against conventional indicators. Ethanol produced a dark-yellow extract with a 19.77% yield, whereas ethyl acetate produced a lighter-yellow extract with a 6.99% yield. The ethyl acetate extract showed no visible color response across pH 1–13, while the ethanol extract remained colorless at pH 1–6 and changed from yellow to orange at pH 7–13. In hydrochloric acid–sodium hydroxide titration, the ethanol extract changed at 7.4 mL and pH 9.6, compared with 6.6 mL and pH 8.8 for phenolphthalein. For acetic acid–sodium hydroxide, the extract responded at 7.5 mL and pH 10.4, while strong acid–weak base titration produced an endpoint at 7.7 mL and pH 2.16. The findings demonstrate solvent-dependent extraction and pH-responsive indicator behavior, with practical applicability dependent on titration chemistry.References
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