compositionink

InkChromatographyExperimentSafetyandFirstAidThissectionwillonlydealwiththespecificsafetyissuesregardingthechemicalsinvolvedandusedinthevideo;othersafetydatamayberequireddependingonthechemicalsused.
Therearelikelytobeothersafetyissuesthatwillneedtobeaddressedoutsidethescopeofthissectionandafullriskassessmentshouldbeperformedpriortoundertakingtheexperiment.
Studentsshouldnotingestanyoftheexperiment;goodlabpracticestartsyoung!
Rubbingalcoholistoxicifingestedandflammable.
Avoidprolongedinhalationoffumes.
FirstAid–washtheaffectedareawithwater.
Ifrubbingalcoholisingested,DONOTinducevomiting;rinsemouthwithwaterandseekmedicalassistance.
GlossaryChromatography–asetoflaboratorytechniquesusedfortheseparationofmixturesCapillaryaction–theabilityofachemicaltoflowintonarrowspaceswithouttheassistanceofanexternalforce,oftenagainsttheforceofgravitySuggestedTeachingPointsAnalyticalscience–thisexperimentwillintroducestudentstoanalyticalsciencebyinvestigatingthechemicalcompositionofinksChromatography–thisexperimentwillintroduceasimplemethodforchromatographyInvestigativetechnique–thisexperimentwillallowstudentstocomparethechemicalcompositionofdifferentinksProblemsolvinganddatainterpretation–pleaseseethe'MurderMystery'sectionofthe"Suggestedimprovements/studentchallenge"sectionWhattoExpectPleaseseethevideoforadetaileddepictionoftheexperiment.
Inthisexperiment,wewillbeinvestigatingthedifferentchemicalcompositionsofaselectionofinks.
Inordertoachievethis,wewilluseananalyticaltechnique,knownaschromatography,toseparateoutthedifferentmixturesofchemicalspresentintheink.
Forthisexperiment,filterpaperandasolvent(eitherwaterorrubbingalcoholinourcase)willseparateoutthechemicals.
Asmallsampleoftheinktobeinvestigatedisplacedonthebottomofthefilterpaperandthesolventallowedtobedrawnthroughthefilterpaperviacapillaryaction.
Asthesolventpassestheink,anychemicalsthatdissolveinthesolventwillbecarriedalongasthesolventcontinuesupthefilterpaper,whileinsolublechemicalswillremainatthebottom.
Thedistancethateachseparatechemicaltravelsupthefilterpaperisdependentonhowwellitdissolvesinthesolventandhowstronglyitbindstothefilterpaper.
Forachemicalthatdissolveswellinthesolventanddoesnotbindtothefilterpaper,itwilltravelmuchfurtherthanachemicalthatdissolveswellbutbindsstronglytothefilterpaper.
Oncethesolventhasreachedthetopofthefilterpaper,eachinkwillleavebehindaspecificcharacteristicpatternshowingthemixtureofchemicalsthatwerecontainedintheink.
EquipmentandChemicalsWaterRubbingalcoholFilterpaperPencilSelectionofdifferentinksSupplementaryInstructionsThebaselinemustbedrawninpencil.
Ifyouuseapen,theinkmaymoveandmixwiththeinksyouareinvestigating.
Itisessentialthatthelevelofsolventisbelowthepencilbaselineanddoescomeintocontactwithanyoftheinksyouareinvestigating.
Toincreasetherateatwhichthesolventtravelsthroughthefilterpaper,coverthetopofthecontainertomakeanairtightseal.
Tryandhandlethefilterpaperaslittleaspossiblewhilewettopreventtearing.
SuggestedQuestionsforStudentsWhatusecouldchromatographyhaveinchemicalindustry–chromatographyisanessentialtechniqueutilisedbyawideofanalyticalprofessions.
Forexample,syntheticchemistsusechromatographytopurifychemicalsbeforetheyareallowedintouse(e.
g.
pharmaceuticaldrugs).
Otherusesincludeforensicscienceandcheckingthepurityofwater.
Whydoinkshavedifferentcolouredchemicalsinthem–inkstendtohaveavarietyofdifferentcoloureddyestogivethedesiredoverallcolour.
Thisisdemonstratedinthevideoshowingthatgreenhighlightersaremadeofablueandyellowdye.
SuggestedImprovements/StudentChallengeUseothersolvents–studentscouldinvestigatehowothersolventsseparateoutthedifferentchemicalspresentinink.
Ethylacetateandacetone(foundindifferenttypesofnailvarnishremover;seetheingredientslabelforwhich)couldbeused;remembertocompleteanewriskassessmentforthis!
Murdermystery–ascenariocouldbesetupinwhichstudentsundertaketheroleofaforensicscientist.
Thestudentscouldbegivenasampleofinkandtoldthatthiswasfoundonthe'victim'.
Thestudentsshouldthenbegivenaselectionofotherinks,whichprovideuniquedyepatternswhenseparated,thathavebeenobtainedfromthe'suspects'.
Thestudentswouldthencomparethe'victim'samplewiththoseofthe'suspects'todiscoverwhowasresponsible.
CleanupandWasteDisposalThespecificwastedisposalprotocolsforthisexperimentwilldependuponthechoiceofliquidsused.
Spillagescanbecleanedwithwaterandpapertowel.
Filterpapercanbedisposedofinthebin.