Capparis decidua as
Natural pH Indicator
Rushikesh M. Birajdar*,
Chandrakant S. Magdum, Shrinivas K. Mohite, Asma D. Ambekari, Smita R. Patil,
Ganesh B. Vambhurkar, Sandeep R. Kane.
Rajarambapu College of
Pharmacy, Kasegaon, Dist – Sangli, Maharashtra, India – 415404.
*Corresponding Author E-mail: rushikeshbirajdar123@gmail.com
ABSTRACT:
Acid –base indicators shows
change in color after change in pH of medium, and the flower extract of various
plants shows sharp color change with change in pH of reacting medium. The study
has been carry out to replace the synthetic indicator with Capparis Decidua
flower extract, because synthetic acid base indicators have some disadvantages
like complicated method of preparation, high cost and they may causes the
environmental pollution or may cause harm to user. The ethanolic extract of
Capparis Decidua flower is done to determine the indicator activity of Capparis
Decidua flower and compared with phenolphthalein indicator. Four deferent types
of neutralization titrations like HCl Vs NaOH, HCl Vs NH3,
CH3COOH Vs NaOH, and CH3COOH Vs NH3
are done to get precise and accurate results. This research work proves that we
can use Capparis Decidua flower extract as a substitute for synthetic acid base
indicator in various acid-base titrations.
KEYWORDS: Natural indicator,
Capparis Decidua flower extract, acid- base titration, neutralization
titration, phenolphthalein.
INTRODUCTION:
The plant Capparis decidua
(Forsk.) Edgew. Belongs to family Capparaceae[1], a small much
branched tree or shrub of arid regions in Africa, Middle East and Southern
Asia, including the Thar Desert[2]. It occurs in vegetative cover in
dry, hot, sandy desert and arid regions where little else grows and is an
extremely hardy species. It is a bushy shrub in dense tufts, 4-5 m high, or
occasionally a small tree with many green vine-like apparently leafless
branches, hanging in bundles. Bark turns whitish-grey color with age, but most
branches and twigs are a glossy dark green.
Small, light brown caducous, linear 1-2cm long
apex short, stiff, pale mucrolike prickle occur in pairs on the twigs at each
node; flowers red or pink, rarely yellow in lateral corymbs, berries globose or
ovoid 1-2cm in diameter, dull red; seed globose, 2-5mm in diameter[3].
Figure 1: Capparis
decidua
Most of the commercial or
synthetic indicators are more costly than natural indicator and also have some
harmful effects like environmental pollution[4][5][6]. Due to this
reasons there is increase in search for alternative indicator take place which
is mainly from plant sources. Because this source is easily available, chief,
and environment friendly. These natural indicators are used in volumetric
analysis for quantitative determination of both inorganic and organic acid
interaction with strong and weak acid or bases, this indicators may shows
intermediate or end stage of acid base reaction by changing the color of
solution[7]. Change in colour of solution is depend on acidity and
basicity of property of solution [8]. Numbers of acid base titration
itself gives the end point by changing the colour of reaction medium
[9][10]. Most of the electron donating and electron accepter substance means
weak acid or base acts as pH indicator. Now day automated titrations apparatus
are used to determine the equivalent point between two reacting substance but
still indicators are used in laboratories for simple titration. Flavanoids
present in flowers and fruits are colored and pH sensitive, hence we can use
fruit extract in various acid base titration as acid-base indicator. Because
pulp of fruit is also pH sensitive due this it gives change in color i.e. pink
at acidic condition and greenish in basic condition. Result obtained from
titration using flower or fruit extract matches with result obtained from
standard indicator. Some organic compounds are responsible for the colours of
flowers are anthocyanins, anthraquinonoids, and flavones. Moto behind this
study is to increase use of traditional medicine and use of plant pigment as
natural indicator instead of synthetic one [11].
REVIEW OF LITERATURE:
Pigments extracted from
Acalypha wilkesiana, Hibiscus Rosa-Sinensis, Allamanda cathartica, rose
etc. used as natural indicator most of the authers report that how natural
indicators are effective than synthetic one e.g. Helianthus annus,
Acalypha wilkesiana, red rose, Beetroot extracts. The extract of
above-mentioned plant was prepared using alcohol, methanol or water for use as
natural indicator.
METHODOLOGY:
Plant materials:
Fresh flowers of Capparis
Decidua are collected from Beed district region, Maharashtra, India. It was
then authenticated at Kusumtai Rajarambapu College Islampur.
Reagents:
To carry out the research work
various analytical grade reagents are used e.g. Sodium hydroxide, ammonia,
hydrochloric acid, ethanol, and phenolphthalein. Which are obtained from
department of chemistry Rajarambapu College of Pharmacy, Kasegaon. The reagent
and solutions are prepares according to procedure given in Indian Pharmacopoeia
1996.
Glass wares:
Calibrated apparatus are used
to perform practical work e.g. Burettes, pipettes, beaker, measuring cylinder,
funnel etc.
Preparation of flower extract:
20gm of Capparis Decidua
flower petals are cut into small pieces then these petals are soaked into
ethanol for 24 hrs for extraction of pigment present in flower. Then after 24
hrs solution is filtered to get pure ethanolic extract of Capparis Decidua
flower which we can use as natural indicator.
Test for
color change:
Measured amount of Capparis
Decidua flower extract i.e. 0.1ml is added into 25 ml of buffer solutions of pH
ranging from 1 to 14. Then this buffer solution is treated with acid or base up
to cooler change.
Titrations:
0.1 ml of flower extract was
added as indicator in the titration of HCl Vs NaOH, HCl Vs NH3, CH3COOH
Vs NaOH, and CH3COOH Vs NH3 and these titrations repeated
for 5 times to get precise results. Same titrations are done using
phenolphthalein as indicator then both result obtained from titration using
plant extract and titration using phenolphthalein are compared. Result obtained
from these titrations is mentioned in the tables 1A to 4B.
The equivalence point of
titration by using Capparis Decidua flower extract is very close to equivalence
point of titration by using phenolphthalein as indicator in acid-base
titrations. But in some cases flower extract shows good result as compared to
phenolphthalein with sharp color change in both the directions.
Hence from the study Capparis
Decidua flower extract we can realize that, flower extract can act good
substitute to phenolphthalein indicator because of simple method of
preparation, accurate results and good performance.
RESULTS:
Table No: 1A: Titration of HCl
against NaOH using Capparis Decidua Flower extract
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
9.0 |
9.10 |
|
2 |
10 |
00 |
9.3 |
|
|
3 |
10 |
00 |
9.1 |
|
|
4 |
10 |
00 |
9.0 |
|
|
5 |
10 |
00 |
9.1 |
|
Table No: 1B: Titration of HCl
against NaOH using phenolphthalein
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant (ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
9 |
9.10 |
|
2 |
10 |
00 |
9.1 |
|
|
3 |
10 |
00 |
9.3 |
|
|
4 |
10 |
00 |
9.0 |
|
|
5 |
10 |
00 |
9.0 |
|
Table No: 2A: Titration of HCl
against NH3 using Capparis Decidua Flower extract
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
9.5 |
9.56 |
|
2 |
10 |
00 |
9.3 |
|
|
3 |
10 |
00 |
9.4 |
|
|
4 |
10 |
00 |
9.9 |
|
|
5 |
10 |
00 |
9.7 |
|
Table No: 2B: Titration of HCl
against NH3 using phenolphthalein
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
10.5 |
10.40 |
|
2 |
10 |
00 |
10.7 |
|
|
3 |
10 |
00 |
9.5 |
|
|
4 |
10 |
00 |
10.6 |
|
|
5 |
10 |
00 |
10.7 |
|
Table No: 3A:-Titration of CH3COOH
against NaOH using Capparis Decidua Flower extract
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
6.0 |
6.14 |
|
2 |
10 |
00 |
6.2 |
|
|
3 |
10 |
00 |
6.3 |
|
|
4 |
10 |
00 |
6.0 |
|
|
5 |
10 |
00 |
6.2 |
|
Table No: 3B:-Titration of CH3COOH
against NaOH using phenolphthalein
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
6.3 |
6.14 |
|
2 |
10 |
00 |
6.0 |
|
|
3 |
10 |
00 |
6.3 |
|
|
4 |
10 |
00 |
6.1 |
|
|
5 |
10 |
00 |
6.0 |
|
Table No: 4A:-Titration of CH3COOH
against NH3 using Capparis Decidua Flower extract
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
9.2 |
9.14 |
|
2 |
10 |
00 |
9.3 |
|
|
3 |
10 |
00 |
9.0 |
|
|
4 |
10 |
00 |
8.9 |
|
|
5 |
10 |
00 |
9.3 |
|
Table No: 4B: Titration of CH3COOH
against NH3 using phenolphthalein
|
S. No. |
Volm of acid (ml) |
Burette reading |
Volm of Titrant(ml) Mean =£x/n |
|
|
Initial (ml) |
Final (ml) |
|||
|
1 |
10 |
00 |
9.5 |
9.54 |
|
2 |
10 |
00 |
9.3 |
|
|
3 |
10 |
00 |
9.9 |
|
|
4 |
10 |
00 |
9.5 |
|
|
5 |
10 |
00 |
9.5 |
|
ACKNOWLEDGEMENT:
Authers are highly Acknowledge
to the help of technical staff of Rajarambapu college of pharmacy, Kasegaon.
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Received on 17.12.2019 Modified on 31.01.2020
Accepted on 21.02.2020
©Asian Pharma Press All Right Reserved
Asian J. Pharm. Ana. 2020; 10(1):37-39.
DOI: 10.5958/2231-5675.2020.00008.3