Chromatography

background [prelab assignment (15 points); due at the beginning of the lab]

brief description on the applications of chromatography

using the concept of IMF, describe the basis of adsorption chromatography; include / define the terms "stationary-" & "mobile-" phase in your response  [hint]

MSDS data on isopropyl alcohol

purpose

analzye (i.e. separate) the dyes in Cool-Aid Grape drink mix

materials

Sep-pak C-18 cartridge, a reverse phase chromatography column material

syringe (1 & 10 mL); microplate (to collect eluant (solution coming out of the cartridge)); pipets

Cool-Aid Grape drink mix; water

70% isopropyl alcohol ("ROH");  red, blue, & purple pencils  (supply your own pencils)

methods [delegate work]

rinse cartridge with ~5 mL 70 % ROH, followed by ~5 mL water & ~ 5 mL air

load ~1 mL Cool-Aid Grape solution onto cartridge

elute (apply ~ 7 mL ROH (or water) using 10 mL syringe onto cartridge at a rate of ~ 1 drop / second), collect ~5 drop eluant and record your observations (see content of lab report; e.g. use colored pencils) until no changes are seen in the column or eluant.

experiment #	elute with ~10 mL
1	water
2	70 % ROH
3	15 % ROH
4	5% ROH, then 70% ROH

at the end of each experiment, rinse cartridge with ~5 mL 70 % ROH, followed by ~5 mL water & ~ 5 mL air; reload cartridge with Kool-Aid, then eluate with the next experimental condition.

for experiment 3, prepare 15 % ROH (i.e. mix 1.5 mL 70 % ROH + 5.5 mL water)

for experiment 4, prepare 5% ROH (i.e. 0.5 mL 70% ROH + 6.5 mL water)

Content of lab report [20 points; no lab report revision]

results   [10 points]

draw / describe the color of the eluant  AND  cartridge in each experimental condition as a function of the fraction number

discussion   [10 points]

rationalize any 3 of your experimental observations based on the concept of IMF - hints:  hydrophobic attraction & reverse phase chromatography (read section on polarity) & chemical structures of various chemicals in this lab (shown below):

(source:  stationary phase's surface)	(source:  isopropyl alcohol - mobile phase)
(source:  blue dye)	(& red dye)