Thin-Layer Chromatography
Joseph Personelli Lab Partners: Dominic Gonzlez & Benjamin Lowry Chem. 24 Dr. Joseph !appel Lab "ssistant: #tacey $en%i'tia Jan'ary 2() 2*+
Abstract: ,he p'rpose o- this eperiment was to 'se a thin/layer chromatoraphic
techni0'e to calc'late retention -actors in or%er o r%er to %etermine the i%entity o- two 'n1nowns. ,hin/Layer chromatoraphy is a techni0'e 'se% to separate a sample so that the sample can be analyze% an% the p'rity %etermine%. t was hypothesize% that thin/layer chromatoraphy co'l% be 'se% to calc'late 3 - al'es that can be compare% to 3 - constants to %etermine the i%entity o- 'n1nown s'bstances. ,he hypothesis was accepte%. ,he 'n1nowns o- trial three were %etermine% to be ca--eine an% aspirin base% on the ,LC techni0'e 'se%.
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,he p'rpose o- this eperiment was to 'se a thin/layer chromatoraphic techni0'e to calc'late retention -actors in or%er to %etermine the i%entity o- two 'n1nowns. ,hin/ Layer chromatoraphy is a techni0'e 'se% to separate a sample so that the sample can analyze% an% the p'rity %etermine%. Chromatoraphic techni0'es 'tilize absorptie an% %istrib'tie properties o%i--erent compo'n%s an% solents. ,here are two phases) a stationary soli% ph ase an% a mobile li0'i% phase. ,he stationary phase is the s'r-ace that is 5staine%6 with a compo'n% yo' want to %etermine) in this case) the polarity o-. ,he mobile phase is the solent that the stationary phase is place% into an% is absorbe%. "s this solent rises 'p the stationary phase) it moes with it the blotte% compo'n%s on the stationary phase. ,he %istance -rom the solent -ront is then 'se% to calc'late the R f al'e o- the compo'n%. 3etention -actors 7 R f 8 are the %istance traele% by the s'bstance %ii%e% by the %istance traele% by the solent -ront*. ,he retention -actors o- s'bstances are a constant an% can be compare% to help %etermine the s'bstance an% the p'rity o- that s'bstance.
7acetaminophen8
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7ca--eine8
7"spirin8 Materials and Methods:
Please re-er to Chapter ) ;periment * on paes <(/<< o- $icroscale =ranic Laboratory with $'ltistep an% $'ltiscale #yntheses by $ayo) Pi1e) an% >orbes -or in-ormation rear%in the metho% an% 'tilization o- ,hin La yer Chromatoraphy 7,LC8. ,here were no a%j'stments ma%e to the eperimental proce%'re.
Results: Table 1: Trial 1 Thin-Layer Chromatography (Ethyl Acetate) ubstance !istance Tra"eled "cetaminophen 9.+ cm +.9 cm "spirin 4.2 cm +. cm Ca--eine 2. cm 4.4 cm Co/#pot 2. cm 4. cm +. cm #olent >ront +.? cm Table1: ,his table shows the %istance that each s'bstance traele% %'e to the solent ethyl acetate carryin it 'p the stationary phase plate. ;ach s'bstance ha% two %i--erent spots. ,he co/spot %istance represent acetaminophen) aspirin) an% ca--eine respectiely.
Personelli 4 Table #: Trial # Thin-Layer Chromatography ($e%ane) ubstance !istance Tra"eled "cetaminophen *. cm "spirin *.9 cm 9.< cm Ca--eine 4. cm *.9 cm Co/#pot .< cm 4.+ cm #olent >ront +.+ cm Table #: ,his table shows the %istance that each s'bstance traele% %'e to the solent heane carryin it 'p the stationary phase plate. Table &: Trial & Thin-Layer Chromatography ($e%ane) ubstance !istance Tra"eled "cetaminophen *. cm "spirin 9.? cm Ca--eine .4 cm *.+ cm @n1nown *.< cm 4.4 cm Co/#pot *.+ cm 4. cm #olent >ront +. cm Table &: ,his table shows the %istance that each s'bstance traele% %'e to the solent heane carryin it 'p the stationary phase plate. ,his trial ha% the a%%ition o- two 'n1nown a%%e%. Table ': R alues o Trial 1 ubstance "cetaminophen "spirin Ca--eine Co/#pot
R alue
.9 .(24 .94+ .94+
.<
.<*4 .?2 .(+ .?2
Table ': ,his table shows the calc'late% 3- al'es -or trial *. Table *: R alues o Trial # ubstance "cetaminophen "spirin Ca--eine Co/#pot
R alue .*?*
.29 .(9 .*4
.(< .29 .?*?
Table *: ,his table shows the calc'late% 3- al'es -or trial 2. Table +: R alues o Trial & ubstance "cetaminophen
R alue .2
Personelli + "spirin Ca--eine @n1nown Co/#pot
.( .? .9? .9
Table +: ,his table shows the calc'late% 3 - al'es -or trial 9.
Calculations: R alues rom Table + rom Trial & Acetaminophen: ( %istance compo'n% traele% A %istance solent traele%8
7*. A +.8 .2 Aspirin: (%istance compo'n% traele% A %istance solent traele%8
79.? A +.8 .( Caeine : (%istance compo'n% traele% A %istance solent traele%8
#pot *: 7.4 A +.8 .? #pot 2: 7*.+ A +.8 .9 ,nno.n : (%istance compo'n% traele% A %istance solent traele%8
#pot*: 7*.< A +.8 .9? #pot2: 74.4 A +.8 .?? Co-pot: (%istance compo'n% traele% A %istance solent traele%8
#pot *: 7*.+ A +.8 .9 #pot 2: 74. A +.8 .?
.9 .?? .?
Personelli !iscussion:
,he p'rpose o- this eperiment was to 'se a thin/layer chromatoraphic techni0'e to calc'late retention -actors in or%er to %etermine the i%entity o- two 'n1nowns. ,hin/ Layer chromatoraphy is a techni0'e 'se% to separate a sample so that the sample can be analyze% an% the p'rity %etermine%. ,hin/Layer chromatoraphy can also show the polarity o- a s'bstance. ,he -'rther %istance that a 5spot6 traele% the less polar that s'bstance is. n or%er to see the 5spot6 an% the %istance it traele% the stationary phase was place% 'n%er a blac1 liht an% ill'minate%. "-ter %eterminin the %istances o- the spots) the 3 - al'es were calc'late%. t was hypothesize% that thin/layer chromatoraphy co'l% be 'se% to calc'late 3 - al'es that can be compare% to 3 - constants to %etermine the i%entity o- 'n1nown s'bstances. ,hree trials were per-orme% %'rin this eperiment. n trial one the solent that was 'se% is ethyl acetate an% in trial two the solent was heane. n trial three the solent heane was 'se% aain beca'se it showe% the most -aorable res'lts. n eac h o- the trials three 1nown samples were 'se%: acetaminophen) ca--eine) an% aspirin. n trial three) there was an a%%itional 'n1nown compo'n% a%%e%. ;ach o- the samples were place% onto the stationary phase plate an% the plate was then a%%e% to the bea1er containin the solents. ,he solents bean to trael 'p the stationary phase plate an% when it reache% near the top the sheet was remoe% an% note% where the solent -ront reache%. ,his %istance that the solent -ront traele% was 'se% at a later time in the eperiment to calc'late 3 - al'es. "-ter eaporation the plates were place% in the @ liht an% ill'minate%. ,his ca'se% the spots to low so that the %istance -rom the initial %rop spot
Personelli ( can be compare% to the new spot -or calc'lation o- the 3 - al'e. ,ables two an% three show the %istance each spot traele% when place% into heane. "-ter %eterminin the %istance that the spots traele% the retention -actor al'es 73 - 8 co'l% be calc'late% 'sin the 3 - e0'ation: 3 - (%istance compo'n% traele% A %istance solent traele%8. ,ables 4) +) shows the calc'late% 3- al'es -or each trial. =ne reason that there are many spots on the stationary phase plate co'l% be %'e to the solent bein heaily concentrate%. ,his co'l% be era%icate% %'rin -'t're eperiments by a%%in %rops o- another s'bstance to %il'te it. ,able three an% table si show the %istances an% 3 - al'es o- trial three. n trial three) two %i--erent 'n1nowns were place% on the startin line alon with the other a-orementione% s'bstances. "-ter placin the trial three stationary phase plate into the @ liht it co'l% be seen that the 'n1nown spot was a combination o- Ca--eine an% "spirin. ,his was eri-ie% by comparin the 3 - al'es o- trial three to the 3 - al'es o- the preio's trials.
Conclusion:
"-ter %eterminin the 3 - al'es -or trial three an% comparin them to trials two an% one the 'n1nowns were ca--eine an% aspirin. ,he i%entity o- the 'n1nown spots was able to be %etermine% by way o- a thin/layer chromatoraphic techni0'e. ,he hypothesis was accepte%. =ne way to improe the res'lts o- this eperiment is to hae a more %il'te% solent so that the spots arent heaily a--ecte%.
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/ost-Lab 0s:
*-&*: Disc'ss the similarities an% %issimilarities o- ,LC) paper) an% col'mn
chromatoraphy. A: n col'mn chromatoraphy) j'st li1e the name s'ests) a col'mn has a soli%
stationary phase pac1e% into it. ,he mobile phase -lows 'p the col'mn an% is separate% %'e to sol'bility) polarity) an% a%sorption -orces. n paper chromatoraphy) cell'lose paper is 'se% as an a%sorbent 'nli1e the col'mn chromatoraphy. Eoweer in thin/lay chromatoraphy a thin/layer o- al'mina or silica is 'se%. n thin/layer chromatoraphy the mobile phase moes 'p the stationary phase while in col'mn chromatoraphy the mobile phase moes %own the col'mn o- silica. #imilarities o- ,LC an% paper is that both 'se strips o- a -ilter paper as a stationary phase.
*-&2: n -i're +.4* why is a sept'm) not j'st a plain cap) 'se% on the top o- the as
collection t'beF A: " sept'm is 'se% beca'se it allows -or easier remoal o- the collecte% aseo's
b'tenes 'sin a astiht syrine.
Personelli < Reerences:
$ayo) D. .) Pi1e) 3. $.) & >orbes) D. C. 72**8. Microscale Organic Laboratory with Multistep and Multiscale Synthesis. Eobo1en: John iley & #ons) nc.
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