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NAME:Glendon Lewis

DATE:February 6, 2015

TITLE:THIN LAYER CHROMATOGRAPHY

AIM: To identify the components in a plant extract usin thin layer chromatoraphy

APPARATUS/MATERIALS: !ilica TL" plate #plastic bac$in%, "apillary tube, &ea$ers, 'exane,

(cetone, 'ibiscus #plant extract%

METHOD:

1% ( baseline was drawn approximately 1cm from the bottom of the TL" plate)

2% The extract was obtained and dissol*ed in 60+ hexane and 0+ acetone,

-% ( clean capillary tube was used to introduce dissol*ed extract into TL" plate)

% The spotted TL" plate was placed into the bea$er consistin of the suitable sol*ent . 60+

hexane, 0+ acetone)

5% The plate was remo*ed when the sol*ent front was approximately 0)5cm from the top of the

plate)

6% (ll *isible spots were circled with a dull pencil on the chromatoram)

/% Two spots were identified and used to calculate the F *alue)

OBSERVATION:

TLC PLATE SHOWING RESULTS OF THE SEPARATION OF COMPONENTS OF A SOLVENT

MIXTURE OF HEXANE AND ACETONE

CALCULATIONS:

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etention Factor istance mo*ed by solute 3 distance mo*ed by sol*ent

istance mo*ed by sol*ent 5cm

Therefore F *alue distance mo*ed by solute 3 5

For !pot (, distance mo*ed 1)4cm

Therefore F 1)4cm3 5 cm

0)-

For !pot , distance mo*ed -)6cm

Therefore F -)6cm35cm

0)/2

f alue of & 0)2

f alue of " 0)

DISCUSSION:

"hromatoraphy is a techni7ue used the separation and analysis of colored dyes and plant piments)

There are many methods of chromatoraphy) Four of these include, paper chromatoraphy, thin layer

chromatoraphy, as li7uid chromatoraphy and column chromatoraphy )(ll chromatoraphy methodsuse the same principle of mobile phase a li7uid or a as mo*in past a stationary phase) The stationary

phase may be a solid onto which the solutes are adsorbed) The solute molecules partition themsel*es

between the stationary phase and the mo*in phase) this partition is not a true e7uilibrium since the

mobile phase is constantly mo*in past the area on the stationary phase where a particular solute is

adsorbed or dissol*ed )Thus a fresh partition with pure mobile phase , is continually bein setup) The

mobile phase should ne*er become saturated with the solute)

8n thin layer chromatoraphy the stationary phase is a thin layer of a solid such as alumina or silica

supported on an inert base such as lass aluminum foil or insoluble plastic) This plate can be prepared inthe laboratory b usin a slurry o the powder and then carefully o*en dryin) The practice is necessary to

ma$e standard and uniform co*erins of the plates) They can also be obtained from laboratory suppliers

which is the normal practice) The plate is relati*ely small of around 5 cm by 12 cm) The mixture to be

analy9ed is spotted at the bottom of the TL" :late and allowed to dry) This area is labelled as the base

line or the lie of oriin) The plate is placed in a closed *essel such as a co*ered container containin the

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mobile phase so that the li7uid le*el is below the spot) TL" 8s *ery efficient and the sol*ent ascends the

plate by capillary action) urin TL" the li7uid is fillin spaces between solid particles) This techni7ue is

usually done in a closed *essel to ensure that the atmosphere is saturated with sol*ent *apor and that

e*aporation from the plate is minimi9ed before the run is complete) The partition here is between the

solute adsorbed onto the silica or alumina particles *ia polar and hydroen bonded interactions and to a

lesser extent acid base attractions due to the sliht acidity of the silica or alumina plate) The plate is

remo*ed when the sol*ent front approaches the top of the plate and the position of the sol*ent front is

recorded before it is dried) This allows the calculation of the retention factor)TL" has many uses such as

determinin the proress of reactions and in determinin the components of products)

SOURCE OF ERROR:

1) "ontaminations may ha*e occurred while usin the capillary tube)

2) ;nouh solution may not ha*e been spotted to ensure that all the components would be produced)

PRECAUTIONS:

1)