Zinnia bicolor as Natural pH Indicator

 

Asha M. Jagtap*, Ganesh B. Vambhurkar, Akshata S. Gavade, Manohar D. Kengar, Nisha M. Jagtap, Omkar A. Patil.

Rajarambapu College of Pharmacy, Kasegaon, Dist – Sangli, Maharashtra, INDIA – 415404.

*Corresponding Author E-mail: ashajagtap018@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 zinnia 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 zinnia flower is done to determine the indicator activity of zinnia 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 zinnia flower extract as a substitute for synthetic acid base indicator in various acid-base titrations.

 

KEYWORDS: Natural indicator, zinnia flower extract, acid- base titration, neutralization titration, phenolphthalein.

 

 


INTRODUCTION:

Zinnia is a genus of plant belonging to daisy family of the sunflower tribe [1][2]. This is inhabitant to southwestern United States including centre of diversity in Mexico. These flowers have long stem also these flowers observed in variety of bright colors’. Height of this plant is ranges from 10 to 100 cm tall [3].leaves of this plant are stalk less (sessile) and apposite to each other, mostly ovate in shape and color is medium green.

 

 

 

 

Figure 1: Zinnia bicolor

 

Scientific classification:L

Kingdom: Plantae

Clade: Angiosperms

Order: Asterales

Family: Asteraceae

Species: Z. bicolor

Binomial name: Zinnia bicolor

Synonyms: Crassina bicolor (DC.) Kuntze, Mendezia bicolor DC.

 

Zinnia flower is observed in various colors and shapes hence this is popular garden flower, it can survive in hot summer temperature, and it is easily grows from seeds [4]. To grow well this plant requires full sun light, well drained, fertile humid soil. These plants reseed within a year.

 

Most of the commercial or synthetic indicators are more costly than natural indicator and also have some harmful effects like environmental pollution [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 zinnia bicolor are collected from from sangali 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:

20 gm of Zinnia 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 zinnia flower which we can use as natural indicator.

 

Test for color change:

Measured amount of zinnia flower extract i.e. 0.1 ml 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 zinnia 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 zinnia flower extract we can realize that, flower extract can act good substitute to phenolphthalein indicator because of simple method of preparation, accurate resultsand good performance.

 

RESULTS:

Table No: 1A:-Titration of HCl against NaOH using Zinnia Flower extract

S.No.

Volm of acid (ml)

Burette reading

Volm of Titrant(ml)

Mean =£x/n

Initial (ml)

Final (ml)

1

10

00

8.0

 

 

8.10

2

10

00

8.3

3

10

00

8.1

4

10

00

8.0

5

10

00

8.1

 

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

8.1

 

 

8.10

2

10

00

8.1

3

10

00

8.3

4

10

00

8.0

5

10

00

8.0

 

Table No: 2A:-Titration of HCl against NH3 using Zinnia 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

 

 

9.16

2

10

00

9.3

3

10

00

9.4

4

10

00

8.9

5

10

00

8.7

 

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

9.5

 

 

9.40

2

10

00

9.7

3

10

00

8.5

4

10

00

9.6

5

10

00

9.7

 

Table No: 3A:-Titration of CH3COOH against NaOH using Zinnia Flower extract

S.No.

Volm of acid (ml)

Burette reading

Volm of Titrant(ml)

Mean =£x/n

Initial (ml)

Final (ml)

1

10

00

5.0

 

 

5.14

2

10

00

5.2

3

10

00

5.3

4

10

00

5.0

5

10

00

5.2

 

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

5.3

 

 

5.14

2

10

00

5.0

3

10

00

5.3

4

10

00

5.1

5

10

00

5.0

 

 

 

Table No: 4A:-Titration of CH3COOH against NH3 using Zinnia Flower extract

S.No.

Volm of acid (ml)

Burette reading

Volm of Titrant(ml)

Mean =£x/n

Initial (ml)

Final (ml)

1

10

00

8.2

 

 

8.14

2

10

00

8.3

3

10

00

8.0

4

10

00

7.9

5

10

00

8.3

 

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

8.5

 

 

8.54

2

10

00

8.3

3

10

00

8.9

4

10

00

8.5

5

10

00

8.5

 

ACKNOWLEDGEMENT:

Authers are highly Acknowledge to the help and guidance of Dr. M. A. Bhutkar, Patil indrajeet, Chawan rohan and Bilaskar vishal.

 

REFERENCES:

1.       https://www.biodiversitylibrary.org/page/557.

2.       Linnaeus, Carl von Systema Naturae, Editio Decima 2: pp 1189, 1759.

3.       Flora of North America Editorial Committe. Flora of North America.,FNA Vol.21page 3,64-74

4.       Singh AK. Flower Crops: Cultivation and Management, New India Publishing, 2006.

5.       Wadkar KA, Magdum CS and Kondawar MS. Use of Careya arborea Roxb. Leaf Extract as an Indicator in Acid-Base Titrations. Journal: Research Journal of Pharmacy and Technology. 2008; 1(4): 535-536.

6.       Pimpodkar N, Shikalgar S, Shinde N, Bhise S, Surve B. Rhoeo syathacea and Allamanda cathartic extract as a Natural Indicator in Acidometry-Alkalimetry. Asian Journal of Pharmaceutical Analysis. 2014; 4(2): 82-84.

7.       Nair S and Sheetal P. Eco-friendly Indicator from the Leaf Extract of Alternanthera dentate. Journal: Research Journal of Pharmacy and Technology. 2011; 4(7): 2011.

8.       Thote P. Green Chemistry: Study of Acid-Base Indicator Property of Golden Beet Root. International Journal of Research – Granthaalayah. Social Issues and Environmental Problems, 2015; 3(9).

9.       Mendham J, Denny R, Barness J, Vogel T. A Textbook of Quantitative Chemical Analysis. New Delhi, 2004; 6th Ed: pp.335-39.

10.     Patil SB, Kondawar MS, Ghodke DS, Naikwade NS and Magdum CS. Use of Flower Extracts as an Indicator in Acid-Base Titrations. Journal: Research Journal of Pharmacy and Technology. 2009; 2(2).

11.     Pathade KS, Patil SB, Kondawar MS, Naikwade NS and Magdum CS. Fruit herbal alternative to synthetic acid base indicators. International Journal of Chem Tech Research CODEN (USA) 2009; 1:549-51.

 

 

 

 

 

 

Received on 21.05.2018       Accepted on 28.07.2018     

© Asian Pharma Press All Right Reserved

Asian J. Pharm. Ana. 2018; 8(3): 137-139.

DOI: 10.5958/2231-5675.2018.00025.X