Indonesia has a very rich variety of plants, it is said to be among the largest in the world. Among them there are a number of plants that can be utilized as an alternative indicator on acid-base compounds. During this indicator acid bases using many chemicals or litmus. Labratoiun which has no acid-base indicator will be difficult to determine the pH of an acid-base substance. Besides litmus or chemicals, pH meter is quite expensive. Actually acid-base indicator can be made from natural materials from surrounding environment. The principle of the indicator is the material that gives different colors to the acidic and alkaline environments.
The Butterfly Pea flower (Clitoria ternatea) is selected because it is a wild plant that is often found in many fields, besides that the Butterfly Pea flower contains anthocyanin extract which can be used to measure acid and base of a solution. An anthocyanin extract was made using 2 grams of flower of the telang and 50 ml aquades or crushed tap water using mortar and pestle. Furthermore, the mixture is filtered to form an anthocyanin extract.
After the anthocyanin extract was obtained then trials of anthocyanin extract in buffer solution. Initially, some buffer solution is specified at a certain pH to be used as a sample. In order to show the changes generated from the various pHs, a buffer solution of pH 3 and pH 5 represents an acidic atmosphere, buffer solution pH 7 represents a neutral atmosphere, and a solution of pH 9 and pH 13 represents an alkaline atmosphere. Furthermore, the three samples in the raksi tube input approximately 2 ml. After that, the anthocyanin extract that had been made was dropped on each sample (as much as 2 ml). When the anthocyanin extract is mixed in the buffer solution there will be a change of color.
Based on the results of this experiment, it is concluded that extracantocyanin can cause red color change in acidic, blue atmosphere in neutral, and green and yellow conditions at base, or can be seen in table below
|Colour Of Buffer Solution|
(Before Added Extract)
|Colour Of Buffer Solution
(After Added Extract)
|Buffer pH = 3||Colorless||Red|
|Buffer pH = 5||Colorless||Pink|
|Buffer pH = 7||Colorless||Blue|
|Buffer pH = 9||Colorless||Light Green|
|Buffer pH = 13||Colorless||Yellow|
2. Butterfly Pea flower (Clitoria ternatea) Extract As a Universal Indicator Substitute
The universal indicator is generally paper, but there is also a solution, which can indicate the pH range price of a wide solution. If this indicator paper is immersed in the solution it will give a certain color which is then compared to the standard color shown in the container to know the pH of the actual solution. The market price for the current universal indicator is Rp.185,000 in 1 pack (100 Tests), the universal indicator can show the pH by benchmarking the dipped indicator paper into the standard color present on the indicator pack
In above figure showed that a Butterfly Pea Flower extract at pH 1,2,3,4,5,6 and neutral pH of 7. in below figure showed a Butterfly Pea Flower extract at alkaline atmosphere starting at pH 8 to pH 14, at a low pH or acid, the color of the a Butterfly Pea Flower extract shows a stronger and sharper red color while the pH rises its solution gradually into pink, the become purple on weak acid and blue in a neutral atmosphere , green on weak bases, yellow and dark yellow on a strong base atmosphere
To utilize the flower extract of telang as a substitute of universal indicator hence need to do direct comparison between color of ekrak flower solution of telang at certain pH with measurement using universal indicator paper.
In a solution having a pH of 14 with the addition of the flower extract of the telang will give a dark yellow color, while the universal indicator shows the color as the color shown on the pH 14 scale, in a solution having a pH of 13 will give a yellow color when added in the flower extract of the telang, whereas with the indicator paper showing the color scale shown pH 13, and the results are the same for the sample at the other alkaline pH that is at pH 12,11,10,9 and 8
3. Butterfly Pea flower (Clitoria ternatea) Extract As Indicator on Acid-Base Titration
Titration of acid-bases is a conventional method of chemical analysis used to determine the concentrations of acids and bases. Until now the titration method is still used although other methods have evolved by using certain instruments because the titration method is a fairly simple, easy, cheap and safe method when applied to food.
Acid base titration is based on the equivalent point between acid and base. The equivalent point is usually determined by the end point of the titration at the time of acid concentration equivalent to its base concentration. The end point of the titration is characterized by the addition of the substance into the analytical solution so that a color change occurs after the equivalent point occurs. Substances added to the analyte are referred to as indicators. Indicators required for titration purposes usually have a pH range that called pH trajectory.
In this study the flower extract is used as an indicator of phenolphthalein and ethyl red, while the substance used for titration is a strong acid with strong base and strong base acid with strong acid
4. Use of Butterfly Pea Flower (Clitoria ternatea) Extract as an Indicator Water Pollution
River water sample testing conducted in the village of Bejan Siwalan Gresik Indonesia, a researcher village, a river flowing in this village and a source of water comes from rain water, river lately is somewhat tainted because presumably there is disposal of household waste into the river, but when the observed physically invisible. Samples taken from some point in the river, a sample was taken in the upstream area, the sample B in the area near the school, sample C in the river springs and D samples taken near the house and allegedly dumping waste into the river.
Anthocyanin extracts are used to test the river water is made in accordance with the results obtained from the previous stage of research. with comparisons between anthocyanin extract and test solution 1: 1 and has a period of 5-10 from extraction process trials.
River water is the replacement buffer acids and bases used in the initial experiment, is thought to have been contaminated chemicals that are acidic and alkaline and is still neutral. Besides using universal indicator paper or a standard for comparison.
After that, test the pH using anthocyanin extracts from Butterfly Pea Flower . Process and composition used was the same as the first stage of the study and the sample used is 1: 1 (3 ml: 3 ml).
The results of the color changes in this experiment can be seen in the following table
|initial color||After added ekstrak|
|Sampel B||slightly turbid||turquoise|
|Sampel D||slightly turbid||yellowish green|
|Initial color||Indikator universal|
|Sampel B||slightly turbid||8|
|Sampel D||slightly turbid||9|
Based on the results of this experiment, it can be concluded that the extract Butterfly Pea Flower can be used as indicators of water pollution, and can be used to replace the universal indicator. In addition, the anthocyanin extract is more effective to use as an indicator of water pollution when used at a ratio of 1: 1 between anthocyanin extract Butterfly Pea Flower interest and test solutions, extracts derived from materials that contain high levels of anthocyanins, and the span of time between the extraction and testing of the pH does not exceed 30 minutes.
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