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2016 ANNUAL REPORT
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SCIENCE NEWS
IN HIGH SCHOOLS
INHIGHSCHOOLS
AnalyzingPlantPigmentsUsingPaperChromatography
BLACKLINEMASTER4,P1
PART1: INTRODUCTIONTOSPINACHCHROMATOGRAPHY
Directions:Practicethepaperchromatographyprocess
1. Prepareadata tablesimilar to theoneshown inStep8below.
2. Putonyourglovessoyoudon’t transfer theoils fromyourskin to thechromatographypaper. (This is
knownascontaminating thesampleandwillaffectyourresults.)Cutyourchromatographypaperso
it is theright length for thebeakerorcupyouwillbeusing.
3. Placeabout5 leavesofchopped, freshspinach inamortarandadd5mLacetone.Use thepestle to
release thepigment from the leaf.Youwantavery intensecolorsolution.
4. Usingapencil,drawareference lineabout1 to2cm from thebottomof thechromatographypaper.
5. Useapipetteordroppertotransferadropofsolutiontoyourchromatographypapersothatthemid-
dleofthedot isonthereference line.Letthedropdry,thenaddanothertothesamespot.Repeatuntil
thespot isverydark (about20drops).Onlyaddthenext
dropwhenthe last isdry (youcanblowon itgently).
6. Prepareyourchromatographypaperso ithangs froma
pencil (ordowel) justabove thebottomofyourbeaker
(asshown inFigure1).
7. Whenyou’reready togo,addsolventsolution (92%
vinegar8%acetone) to thebottomof thebeakerso the
tipof thechromatographypaper issubmerged,butyour
dot isnot.Leave thebeakeruntouched forabout10 to
20minutes.Watchas thesolvent (mobilephase)moves
up thepaper (stationaryphase)andobservewhathap-
pens to thepigmentdotover time.Remove thechroma-
tographypaper from thesolution justbefore thesolu-
tionreaches the topof thepaper (where it touches the
pencil).Usingapencil,mark thefinalsolvent lineand the
locationofeachpigmentasseen inFigure2 (theseget
harder toread laterwhen thepaperdries).
8. Useyourruler tomeasure thedistanceeachpigment
traveledcompared to thereference lineandrecordyour
dataona table like thisone:
FIGURE1:BEAKERANDPAPERSETUP
FIGURE2:LABELYOURPAPER
Pencil
Chromatography
paper
iswrappedand
hung from thepencil
with itsenddipped in
theacetonesolution
Sample
issuspended
above theacetone
solution
D
S
D
X1
D
X2
Solventflowed tohere
Onepigmentflowed
tohere (X
1
)
Onepigmentflowed
tohere (X
2
)
November 26, 2016
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Onepigmentflowed
tohere (X
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SOCIETYFORSCIENCE&THEPUBLIC
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Scientistsenlistsymbiotic life-form
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AMY KOCHENSPARGER, HIGH SCHOOL OF SCIENCE & TECHNOLOGY, OHIO
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on my students’ learning and love of science!
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