Tukiran, Andika Pramudya Wardana
As known that synthetic acid-base indicators can cause some environmental problems such as chemical pollution, availability problems and high cost. Therefore, many researchers are now trying to find an alternative indicator to substitute the synthetic indicators by optimizing the natural pigment of the plant. Related to this, an attempt to investigate the indicator activity of Thunbergia erecta L. flowers extract as natural indicators had been conducted. Flower pigment of the plant was extracted by maceration using ethanol and 1% HCl. The flower extract showed visible color change at pH from 1 to 14 and its absorbance was measured using a UV-Vis spectrophotometer. The indicator activities of flower extract had been applied in titration using a strong acid-strong base with given concentration. The extract showed an absorption band at 315 and 269 nm. The result showed pH range of indicators presented in at pH from 10 to 11 with 0.382 error percentage. Thus, Thunbergia erecta L. flower can be used as an alternative indicator to be commercial indicators that are more environmentally friendly. © RASĀYAN. All rights reserved.
Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Negeri Surabaya, Jl. Ketintang, Surabaya, 60231, Indonesia
