CHEMSHEETS CHROMATOGRAPHY www chemsheets co uk GCSE 1254
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CHEMSHEETS CHROMATOGRAPHY © www. chemsheets. co. uk GCSE 1254 21 -Aug-2017
PAPER TYPE Mobile phase Stationary phase Paper solvent paper TLC solvent powder Column solvent powder Gas gas powder Separation depends on the relative strength of attraction/affinity of each substance to the mobile & stationary phases
© www. chemsheets. co. uk Analogy Mobile phase Stationary phase Swimmers = = GCSE 1254 21 -Aug-2017 Swimmers in race along a flowing river flowing water river bed mixture to be separated • some swimmers move along with the water quickly (strong affinity to water and swimming) • others move very slowly (poor swimmers – their feet have a strong affinity to the river bed, but do have some affinity for the water so do some swimming and move along) • some may just stand on the spot and not move at all (strong affinity for river bed and no affinity for the water)
TLC TYPE Mobile phase Stationary phase Paper solvent paper TLC solvent powder Column solvent powder Gas gas powder Separation depends on the relative strength of attraction/affinity of each substance to the mobile & stationary phases
COLUMN TYPE Mobile phase Stationary phase Paper solvent paper TLC solvent powder Column solvent powder Gas gas powder Separation depends on the relative strength of attraction/affinity of each substance to the mobile & stationary phases
GAS TYPE Mobile phase Stationary phase Paper solvent paper TLC solvent powder Column solvent powder Gas gas powder Separation depends on the relative strength of attraction/affinity of each substance to the mobile & stationary phases
CHROMATOGOGRAM P is a mixture of A and C A B C D P © www. chemsheets. co. uk GCSE 1254 21 -Aug-2017
Rf values solvent front 10 cm 7 cm Rf = distance travelled by spot distance travelled by solvent = 7 10 = 0. 7 starting line © www. chemsheets. co. uk GCSE 1254 21 -Aug-2017
