CHEMISTRY; INSTRUMENTAL METHODS OF ANALYSIS – CHROMATOGRAPHY QUESTIONS AND CORRECT ANSWERS

CHEMISTRY; INSTRUMENTAL
METHODS OF ANALYSIS –
CHROMATOGRAPHY QUESTIONS
AND CORRECT ANSWERS
ChromatographyA2-A2Ans---
A2groupA2ofA2techniquesA2thatA2involveA2theA2separationA2ofA2mixturesA2ofA2substancesA2
-
A2observationsA2madeA2onA2theA2unknownA2mixtureA2areA2comparedA2toA2observationsA2o
nA2knownA2substancesA2(underA2theA2sameA2conditions)A2
-A2includesA2aA2mobileA2phaseA2whichA2passesA2overA2aA2stationaryA2phaseA2
-
A2eachA2componentA2inA2aA2mixtureA2absorbsA2andA2desorbsA2atA2differentA2rates,A2affectA
2theA2overallA2rateA2ofA2movement


MobileA2PhaseA2-A2Ans---A2theA2solventA2thatA2movesA2acrossA2theA2stationaryA2phase
-A2typicallyA2polar

StationaryA2PhaseA2-A2Ans---A2theA2surfaceA2ontoA2whichA2theA2componentsA2absorb
-
A2whenA2componentsA2absorbA2ontoA2theA2stationaryA2phase,A2thatA2areA2"heldA2inA2place
"A2
e.gA2celluloseA2paperA2inA2paperA2chromatographyA2
-A2mixtureA2isA2carriedA2withA2theA2mobileA2phaseA2intoA2theA2stationaryA2phaseA2
BONDEDA2PHASE:
-
A2isA2aA2stationaryA2phaseA2covalentlyA2bondedA2toA2theA2supportA2particlesA2orA2toA2theA2i
nsideA2ofA2theA2columnA2tubingA2walls

Retention/RetardationA2FactorA2-A2Ans---
A2theA2ratioA2ofA2theA2distanceA2travelledA2byA2theA2substanceA2toA2theA2distanceA2travelle
dA2byA2theA2solventA2
-
A2asA2componentA2hasA2toA2moveA2withA2theA2solventA2itA2cannotA2beA2lessA2thenA2zeroA2o
rA2biggerA2thenA21A2
-A2isA2usedA2toA2identifyA2ofA2substancesA2areA2possiblyA2theA2sameA2
-
A2havingA2aA2smallA2retentionA2factor,A2thereforeA2meansA2componentA2hasA2lowA2desorpti
onA2