lapaoran teleng & epms

7/31/2019 lapaoran teleng & EPMS

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1. Title : Absorption Analysis of EPMS and Acid-Base Indicators byUsing UV-Visible Spectrophotometer

2. Objective :- Determining the absorption of EPMS- Determining the absorption ofTeleng flower(Clitoria ternatea L.)- Determining the absorption of phenolphthalein

3. Basic Theory:Ultraviolet-Visible Spectrometry

Ultraviolet-visible spectrometry is an analytical method based on

molecular absorption using ultraviolet radiation and visible light, with

wavelengths between 160-780 nm. This method is widely used in quantitative

measurement of various inorganic and organic compounds. Ultraviolet light has a

wavelength between 160-400 nm and visible light that humans have typically seen

the wavelength range between 400-800 nm.

Description:

Violet : 400 - 420 nm Indigo : 420 - 440 nm Blue : 440 - 490 nm Green : 490 - 570 nm Yellow : 570 - 585 nm Orange : 585 - 620 nm Red : 680780 nm

Picture 1. Visible Spectrum


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Ultraviolet-visible radiant energy with wavelengths between 160-780 nm

corresponds to the transition of electrons involved in bonding in a molecule. In

organic molecules, radiant energy absorbance in the ultraviolet-visible causes

transition of electrons involved in bonding phi () primarily engaged in the phi

electron conjugation system. Organic molecules have phi electrons involved in phi

conjugated bond. While on an inorganic molecule, absorbance of radiation in the

region appear visible to the transition of electrons in dorbital, and this is more

common in complex compounds, because it is generally colored complex

compounds.

Sunscreen LotionThe wavelength range emitted by the sun's ultraviolet radiation covers that

cannot be viewed eye. Ultraviolet is very dangerous for some types of skin and

therefore skin should be protected with sunscreen lotion to avoid direct irradiation

of the skin from the tropical sun. The sun emits electromagnetic radiation into the

earth's surface with a range of 290 nm to 800 nm.

Range of ultraviolet radiation is divided into two parts roughly UV A:

320-400 nm and UV-B: 280-320 nm. UV-B is responsible for skin damage

(sunburn and tanning). When skin is exposed to ultraviolet radiation, skin cells

will produce brown pigment called melanin and will become more brown skin and

thinning. More and more exposed to ultraviolet radiation in the range 290-320 nm,

the more melanin is formed and the skin will get darker. Furthermore, ultraviolet

radiation causes skin damage to DNA and proteins, thus cause very harmful

effects of skin cancer or melanoma.

In an effort to minimize the effects of direct irradiation of ultraviolet

radiation, various lotions (sunscreen) (sunscreen lotion) have been developed. The

purpose of the lotion or cream is to filter out radiation that can potentially damage

the skin, the wavelength of 290-320 nm. Sunscreen products will be effective if it

contains compounds that can absorb radiation at these wavelengths. Usually more

than one compound should be used to convince a range of radiation is absorbed.

EPMS is extracted from greater is one of the active compound to make sunscreen.


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Ethyl p-Methoxycinnamate (EPMS)

Greater (Kaempferia galanga L.) is one type of drug plants belonging to

the Zingiberaceae. Rhizome or rhizome of this plant contains essential oils and

alkaloids are used as a stimulant. A compound most widely in the rhizome

essential oil of greater is ethyl p-methoxy cinnamate (EPMS). Rhizome isolation

of greater obtained EPMS by 2.4% of dry weight, because it can easily be isolated

from the tuber using a solvent of petroleum ether or ethanol. Ethyl p-

methoxycinnamate crystal has a melting point of about 48o-49

oC.

Ethyl p-methoxy cinnamate (EPMS) is one compound which is the basic

ingredient of sunscreen which protective skin from the sun. EPMS included in the

class of ester compounds containing benzene rings and methoxy group which is

nonpolar and also the carbonyl groups that binding of ethyl are less polar so that

the extraction can use solvents that have a polarity variation such as: ethanol,

ethyl acetate, methanol, water, and hexane.

In isolation experiments of EPMS can be used soxlet extraction method.Separation principle is based on the distribution ratio of solute in two solvents that

do not dissolve each other. Greater-paste, put in soxlet tool that has been wrapped

with filter paper. Extraction sokhlet discontinued when the suspected substance in

the circulation that will be extracted are exhausted, this is indicated by no color

change of solvent after passing through the sample. The organic solvent used in

isolation EPMS using soxlet extraction method is ether. Crystals of ethyl p-

methoxy cinnamate obtained usually is mixed with impurities. Purification can be

O

OC 2H 5

H 3CO

Picture 2. Greater andEthyl p-Methoxycinnamate (EPMS)


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done by recrystallization using ethanol and proceed with the test crystal melting

point EPMS.

Acid-Base Indicators

Acid-base indicator is a substance whose color can change as interact or

react with acidic compounds and basic compounds. Indicators of acid-base

commonly used are artificial and natural indicator.

a. Artificial IndicatorsThe nature of acid/base of a substance can be determined by taste.

However, not all substances to be sampled prior safe chemicals in the laboratory.

Accordingly, for purposes of experimentation, scientists create litmus. Litmus is a

similar substance obtained from the types of lichens (Roccella tinctoria). In

addition to litmus, are still a lot of artificial acid-base indicators such as

phenolphthalein, methyl red and blue bromthymol. Various types of artificial

acid-base indicator and changes color in a solution of acid or base and its pH

range can be seen in the following table:

Indicators

Color

pH range*In acid In base

Blue thymol Red Yellow 1.22.8

Blue bromophenol Yellow Blue purple 3.04.6

Orange methyl Orange Yellow 3.14.4

Red methyl Red Yellow 4.26.3

Blue chlorophenol Yelow Red 4.86.4

Blue bromotimol Yellow Blue 6.07.6

Red cresol Yelow Red 7.28.8

Phenolphthalein Colorless Reddish pink 8.310.0

* PH range is defined as the range in which the indicator color changes from

acid to alkaline color

Phenolphthalein is one of artificial indicator. Phenolphthalein as an acid-

base indicator, and will know that it is colorless in acidic conditions and magenta


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(bright pink) in an alkaline solution. This color change related to changes in the

molecule explains below:

The structures of the two differently colored forms are:

Both of these absorb light in the ultra-violet, but the one on the right also absorbs

in the visible with a peak at 553 nm.

The molecule in acid solution is colorless because human eyes can't detect

the fact that some light is being absorbed in the ultra-violet. However, human eyes

do detect the absorption at 553 nm produced by the form in alkaline solution. This

absorption at 553 nm is in the green region of the spectrum (the complementary

color of green is magenta - and that's the color human see).

Human have is a shift to absorption at a higher wavelength in alkaline

solution. As human have already seen, a shift to higher wavelength is associated

with a greater degree of delocalization. Here is a modified diagram of the

structure of the form in acidic solution - the colorless form. The extent of the

delocalization is shown in red.

Notice that there is delocalization over each of the three rings - extending

out over the carbon-oxygen double bond, and to the various oxygen atoms

because of their lone pairs. But the delocalization doesn't extend over the whole


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molecule. The carbon atom in the centre with its four single bonds prevents the

three delocalized regions interacting with each other. This is comparison with the

magenta form:

The rearrangement now lets the delocalization extend over the entire ion.

This greater delocalization lowers the energy gap between the highest occupied

molecular orbital and the lowest unoccupied phi anti-bonding orbital. It needs less

energy to make the jump and so a longer wavelength of light is absorbed.

b. Natural IndicatorsBesides the artificial indicators such as phenolphthalein, methyl red and

blue bromthymol, compound acid/base can be identified by using natural

indicators, such as hibiscus, turmeric, red cabbage and various other plant species.

The procedures for making a natural indicator of flower are as follows:

- The characteristics of a good flower used as a pH indicator that is stillfresh flowers dark colored (light), used only crown flower, while stamen

and pistil not in use.

- In the preparation of liquid indicators, flowers are washed with cleanrunning water for flower color pigments are intended to not participate

soluble in water.- Flower that has been washed and cut into small pieces to expand the

surface so that the process of dissolution rates of flower more effectively.

The more surface area of flower, the more color pigment of flower is

soluble in the leaching process. In the process of cutting, flower does not

chopped into small pieces.

- After cut flower, dried flower later in the oven to reduce the water contentcontained, conducted at a temperature of 50C for 15 minutes. At these


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temperatures, flower pigments have not changed so that when dissolved

will produce a readily observable color. When drying performed at a

temperature greater than 50C then the flower color will change because

the characteristics of early flower color is lost.

- Dried flowers are already included in the jar and alcohol 70% is added toapproximately 0.5 cm submerged flowers.

- Flowers left in place overnight for flower color pigment soluble in alcohol.Alcohol is actually 70% ethanol, which was chosen as a solvent in

addition to views of polar characteristics also be seen from the economic

aspect. Ethanol is more readily available and cheaper than other types of

alcohol. The use of solvents to dissolve the flower used to taste because if

excessive then the resulting solution will be diluted, causing the resulting

product is less good.

- After last night, the solution is filtered to obtain filtrate flower extract.Flower extract is a liquid indicator. Then the indicator liquid is poured in

another jar and stored in a refrigerator until used.

- How to use liquid indicator that these indicators shed on the solution to betested for its pH. Solution will provide the color change and then change

the color matched the color of the route pH indicator. Each color on the

route has different pH. The color of the same solution with the color on the

route showed that the pH of the solution pH equal to pH at pH route

indicator.

Flower is used as a natural indicator by observer is teleng flower. These

plants spread and usually found in the yard or forest edge. This plant family of the

tribe of legumes (papilionaceae) is derived from tropical Asia, but now has spread

throughout the tropical regions. Teleng flower(Clitoria ternatea L.), known as

the blue flower, telang flower. Teleng flower has a variety of chemical

constituents, including: saponins, flavonoids, alkoloid, Ca-oxalate and sulfur,

especially its leaves: kaempferol 3-glucoside and triterpenoids. The flowers also

contained delphinidin 3.3'.5' and triglucoside, phenol. Roots are poisonous.


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Picture 3. Teleng flower

Since the first plant in the garden is planted as an ornamental plant because

the flowers are bright blue. The flowers in various parts of Southeast Asia are

used as food coloring or cake. In Malaysia, crown flower extract is used to color

the sticky rice. In Thailand, the flowers are used as blue-colored beverages. Other

variety of this flower is a flower with a white crown.

4. Chemical and Chemical Apparatus :In this experiment, the chemical and chemical apparatus used are:

Apparatus Amount Chemicals Description

Digital Scales 1 solution of EPMS 10 mL

volumetric flash 25 mL 1 piece Clitoria ternatea L. 15 tangkai

volumetric flash 50 mL 1 piece Ethanol 500 mL

volumetric flash 100 mL 1 piece distillate water 500 mL

Mortar and pastle 1 set solution of PP 10 mL

Measuring pipette 5 mL 1 solution of HCl 0,1 M 5 mL

beaker 100 mL 1 piece solution of NaOH 0,1 M 5 mL

Spatula 1 piece

dropped 3 pieces

Watch glass 1 piece

stirring rod 1 piece


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Petri dish 1 piece

UV-Vis

spectrophotometer

1 set

tube 12 piece

Tube rack 1 piece

5. Procedure and Observation ResultPart I : Measurement EPMS

No Work procedures Observations

1 EPMS is still in the form of slightly

viscous liquid was dissolved by

using 95% ethanol.

EPMS slightly brown colored fluid. When

reconstituted with 95% ethanol solution formed a

transparent brown.

2 Cuvette is filled with EPMS solution,

then measured spectrum by using

95% ethanol as a reference sample.

EPMS spectra measurement, there are two peaks

where the maximum absorption at a wavelength of

307.0 nm with the absorbance is 1.834.

Part II : Measurement of Teleng Flowers


1 Flowers teleng smoothed by using a

mortar and pestle.

Teleng Flowers (Clitoria ternatea L.) is a blue

flower. When mashed produced little dark purple

liquid.


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2 Flowers that have been mashed

dissolved using 95% ethanol.

When reconstituted with using ethanol solution

remained purple.

3 Cuvette filled with extracts of

Teleng flower then measured

spectrum by using 95% ethanol as a

reference sample.

In the spectrum measurement teleng flower extract

contained five peaks where maximum absorption at a

wavelength of 211.0 nm with the absorbance is

1.042.

4 Extracts that had been measured

earlier added a few drops of HCl 0.1

M. Furthermore, its spectrum was

measured again.

In the spectrum measurement extracts of teleng

flower were added with HCl there are four peaks

where maximum absorption at a wavelength of 268.0

nm with the absorbance is 1.022. When the first

extract ofteleng flower purple plus HCl solution

turns red.


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5 Teleng flower extract on cuvette

replaced with a new pupil flower

extract and then added a few drops

of NaOH. Next measured spectrum.

In the spectrum measurement teleng flower extract is

added with NaOH there are five peaks where

maximum absorption at a wavelength of 277.0 nm

with the absorbance is 0.826. When the first extract

of teleng flower purple plus NaOH solution

changes color to green.

Part III : Measurement of PP


1 PP solution made by dissolving 1

gram of solids into a 100 mL

phenolphthalein aquades.

PP is a white solid. When diluted with water does not

all dissolve PP. Colorless solution was formed.


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2 Cuvette filled with a solution of PP

and its spectrum was measured using

95% ethanol as a reference sample.

In the spectrum measurement of PP solution there are

three peaks in which the maximum absorption at a

wavelength of 229.0 nm with the absorbance is

0.396.

3 Cuvette filled PP solution is then

added with HCl and measured

spectrum.

In the spectrum measurement of PP were added to a

solution of HCl, there are three peaks in which the


with the absorbance is 0.329. PP solution is a

colorless solution when added to HCl solution

remains colorless.

4 Cuvette PP filled with a new

solution is then added with NaOH

then measured spectrum.

In the spectrum measurement of PP were added to a

solution of NaOH, there are two peaks where the


with the absorbance is 0.407. PP solution is a

colorless solution when added to the NaOH solution

became pink.

6. DiscussionThe discussion of this experiment are :

Wavelength Absorption Determination of Compound Lotion Active Ingredients

in Sunscreen EPMS

In this experiment the wavelength of absorption measurements were taken

the active ingredients in products sold sunscreen free. One of the active compound

in question is ethyl the methoxycinnamate. Before the measurement wavelength

absorption in these compounds, the methoxy ethyl which is in the form of viscous

liquid was dissolved in ethanol. Ethanol solvent was chosen because a compound

will be dissolved (EPMS) are compounds that dissolve in organic solvents besides

ethanol also showed no absorption at 200-1000 nm spectral region. This ethanol

solution was put into cuvette. Subsequently a solution of ethyl p-


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methoxycinnamate which has been diluted and incorporated into spectra cuvette

measured.

EPMS is one of the active ingredients found in sunscreen lotions. EPMS

Solution absorbance was measured with UV-Vis spectrometer instrument, the way

to put the solution on cuvette and operated tool for measuring absorbance. The

EPMS absorption curve generated from UV-Vis instrument as follows.

From the absorption curve above can be seen that the absorption EPMS

gives two peaks and one valley, where the highest peak shows a maximum

absorption of Ethyl p-methoxycinnamate which occurs at a wavelength of 307 nm

with 1.834 absorbance.

Determining The Absorption ofTeleng Flower(Clitoria Ternatea L.)

Teleng flowers or Clitoria ternatea L. is blue flowers that including

Papilionaceae family of plant. The variety chemical content, already been known

that is: Saponins, flavonoids, alkoloids, Ca-oksalat and sulphur. In this experiment

the flower was crushed and dissolved in ethanol produces a dark purple solution.

After that the Solution was diluted with ethanol until the color is transparent. This

diluted solution that has been tested by UV-Vis and obtained the following data:

Figure 4. EPMS absorption curve


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Figure 5. Absorbance curve of neutral solution

From the curve is known that compound on solution of Clitoria ternatea

L. solution can absorb light with a wavelength of 211.0 nm with absorbance 0168,

wavelength 268.0 nm by absorbance 0179, wavelength 308.0 nm by absorbance

0870, at a wavelength of 577.0 nm with 1.012 absorbance , at a wavelength of

623.0 nm with the absorbance of 1.042. This shows that the compound on Clitoria

ternatea L. solution can absorb visible light (wavelength 577.0 nm and 623.0 nm)

and ultraviolet light (wavelength 211.0 nm, 268.0 nm, and 308.0 nm). But there is

maximum absorption at a wavelength of 211.0 nm that is equal to 1.042 so that

the maximum absorb ultraviolet radiation and can be used as a sun screen lotion.

Not only absorption test in neutral circumstances, but also absorbance at

acidic and alkaline conditions ofClitoria ternatea L. solution was determined. To

pickle Clitoria ternatea L. solution, some of 0.1 M HCl was added and the color


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of solution turns red. This solution was tested by UV-Vis absorbance. From the

measurement results obtained the following data:

Figure 6.Absorbance curve ofClitoria ternatea L. solution in acidic

conditions

From the curve is known that Clitoria ternatea L. solution in compounds

in acidic conditions can absorb light with a wavelength of 225.0 nm with

absorbance 0845, wavelength 268.0 nm by absorbance 1.022, wavelength 299.0

nm with the absorbance of 0.884, and at a wavelength of 549.0 nm with the

absorbance 0174. This shows that the compound on Clitoria ternatea L. solution

can absorb visible light (wavelength 549.0 nm) and ultraviolet light (wavelength

299.0 nm, 268.0 nm, and 225.0 nm). But there is maximum absorption at a

wavelength of 268.0 nm that is equal to 1.022 so that it can absorb ultraviolet

radiation and can be used as a sun screen lotion.


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Furthermore, to Clitoria ternatea L. solution in a state of alkaline

condition can be made by adding 0.1 M NaOH solution, the solution changes

color to green. From the measurement results with UV-Vis data obtained

following data:

Figure 7. Absorbance curve ofClitoria ternatea L. solution in an alkaline

condition

From the curve is known that Clitoria ternatea L. solution in alkaline

conditions, which can absorb green light with a wavelength of 229.0 nm with

absorbance 0.738, wavelength 277.0 nm by absorbance 0.826, wavelength 312.0

nm by absorbance 0.558, at wavelength of 396.0 nm with absorbance 0.617, and

at a wavelength of 593.0 nm with the absorbance of 0.092. This shows that the

compound on Clitoria ternatea L. solution can absorb visible light (wavelength

593.0 nm) and ultraviolet light (wavelength 229.0 nm, 277.0 nm, and 312.0 nm,

and 396 nm). But there is maximum absorption at a wavelength of 277.0 nm that


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is equal to 0.826 so that the maximum absorb ultraviolet radiation and can be used

as a sun screen lotion. From these observations may also note that the flower

extract Clitoria ternatea L. can be used as an indicator of acid-base due to show

obvious color changes. It changes because of anthocyanin that contented on the

flowers. Anthocyanin is one kind of flavonoid that has conjugated double bond.

This bounding make the flowers can absorb visible light. This following figure is

the structure of anthocyanin

Figure 8. Structure of anthocyanin

Wavelength Absorption Determination of PP In The State of Acids and Bases

The wavelength of absorption measurements was taken the active

ingredients in the PP (phenolphthalein). The structure of PP when added with the

acid and base are as follows.

Figure 9. Fenolfttalein reaction with acids and bases

PP In Neutral Condition

Before the measurement wavelength absorption in the compound, the PP

is in the form of a white crystalline solid that is dissolved in distillate water. After

reconstitution formed a colorless solution. First of all water put into cuvette one as

a reference. Furthermore, PP solution incorporated into the two and spectra


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measured. PP neutral solution absorbance measured by UV-Vis spectrometer

instrument, the way to put the solution on cuvette and operated tool for measuring

absorbance. The PP neutral absorption curve generated from UV-Vis instrument

as follows.

From the absorption curve above can be seen that the absorption of PP

gives three peaks, namely at a wavelength of 342.5 nm with 0.130 absorbance, at

wavelength 276 nm with 0.163 absorbance, and at a wavelength of 229 nm with

0.396 absorbance. Where the highest peak is shows a maximum absorption of the

PP that occurs at a wavelength of 229 nm with 0.396 absorbance.

PP In Acid Solution

Then the second experiment, a solution of 0,1 M HCl added PP Once

added, a solution of PP is not being changed. The following reaction is the

reaction between the PP with acid.

Addition of acid (hydrogen ions) excess will shift the position of

equilibrium to the left, and turn the indicator colorless. As already seen, the shift

to higher wavelength associated with a greater degree of delocalization. Here is a

diagram of a modification of the structure forms in acid solution. Delocalization

level shown in red.

Figure 10. PP neutral absorption


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Figure 11. The level of acid delocalization

Notice that there is delocalization over each of the three rings - extending

out over the carbon-oxygen double bond, and to the various oxygen atoms

because of their lone pairs. But the delocalization doesn't extend over the whole

molecule. The carbon atom in the centre with its four single bonds prevents the

three delocalized regions interacting with each other. So the acid molecule in

solution is colorless because our eyes cannot detect the fact that light is absorbed

in the ultra-violet.

Further absorption wavelength measurement of PP in a acidic atmosphere.

PP solution in acidic conditions was measured absorbance with UV-Vis

spectrometer instrument, the way to put the solution on cuvette and operated tool

for measuring absorbance. The absorption curves of PP in a state of acids

produced from UV-Vis instrument as follows.

From the absorption curve above can be seen that the uptake of PP in a

acidic conditions gave three peaks, namely at a wavelength of 342 nm with 0.079

absorbance, at wavelength 276 nm with 0.108 absorbance, and at a wavelength of

Figure 12. Absorption curves of PP

in an atmosphere of acid


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228.5 nm with 0.329 absorbance. Where is the highest peak of maximum

absorption of the PP in an atmosphere of acid occurs at a wavelength of 228.5 nm

with 0.329 absorbance.

PP In Base Solution

The third experiment, a solution of 0,1 M NaOH added PP once added, the

solution changes color from colorless PP turn pink. The following reactions that

occur between the PP with the bases.

This is caused by the addition of hydroxide ions which remove hydrogen

ions from the equilibrium that leads to the right to replace the indicator change to

pink. In this case occurred the rearrangement now lets the delocalization extend

over the entire ion. This greater delocalization lowers the energy gap between the

highest occupied molecular orbital and the lowest unoccupied pi anti-bonding

orbital. It needs less energy to make the jump and so a longer wavelength of light

is absorbed. The following structures.

In this case, our eyes do detect absorption at 553 nm generated by the

shape of the base solution. Where 553 nm is in the green region of the spectrum.

When seen again the color wheel, will find that the complementary color is

magenta and green color that is being viewed.

Furthermore, uptake measurement wavelength of PP under alkaline

conditions. Alkaline solution of PP in a state of measured absorbance on UV-Vis

spectrometer, by putting the solution on kuvet and operated tool for measuring

absorbance. The absorption curves of PP in alkaline conditions resulting from

UV-Vis instrument as follows.


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Figure 13. Absorption curves of PP under alkaline

From the absorption curve above can be seen that the uptake of PP inalkaline conditions gave two peaks, i.e. at a wavelength of 553 nm with 0.407

absorbance and the wavelength of 370 nm with 0.082 absorbance. Where is the

highest peak of maximum absorption of the PP under alkaline conditions occurs at

a wavelength of 370 nm with 0.082 absorbance.

7. ConclusionAccording to the discussion above, it can concluded that:

a. The absorption of EPMS is 1.834 at a wavelength of 307.0 nmb. The absorption of Teleng flower (Clitoria ternatea L.) is 1.042 at a

wavelength of 211.0 nm

c. The absorption of phenolphthalein is 0.407 at a wavelength of 553.0 nm

REFERENCES

Anonim. 2009. Analysis UV-Visible. Accessed on April 1

st

fromhttp://www.chemguide.co.uk/analysis/uvvisible/theory.html#top

Clark, Jim. 2007. Phenolphthalein. Accessed on April 1st

2011 from

http://www.digipac.ca/chemical/mtom/contents/chapter3/phenolphthalein.

htm

Muderawan, I Wayan. 2010. Analisis Instrumen. Singaraja: Jurusan Pendidikan

Kimia, UNDIKSHA.


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Wikipedia. 2009. Phenolphthalein. Accessed on April 1st

from

http://en.wikipedia.org/wiki/Phenolphthalein

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