Jove Lab Chem
Column Chromatography — Lab Prep
Source: Lara Al Hariri at the University of Massachusetts Amherst, MA, USA
- Preparation of the Dye Solution
Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed.
-
Before you get started, put on a lab coat, safety glasses, and nitrile gloves, and make sure that the lab has a labeled organic waste container.
-
Prepare 5 mL of green food dye solution in ethanol. First, tare a clean empty 5-mL volumetric flask and slowly add 2.5 g of green food dye to the flask.
-
Add about 1.5 mL of 95% ethanol to the flask, stopper it, and seal it with plastic paraffin film.
-
Hold the stopper firmly in place and invert the flask several times to mix the ethanol and food dye together.
-
Then, add 95% ethanol to the fill line, reseal the flask, and invert it until the solution color appears even throughout.
-
Label the flask with its name and concentration and place it in a central area.
-
- Preparation of the Laboratory
-
Ensure that the lab has labeled waste containers for silica gel and glass.
-
Fill a plastic wash bottle with acetone and set it by the organic waste container. This is for students or teaching assistants, who will clean the columns after the lab.
-
Place a container of silica gel powder, a container of sand, a box of laboratory wipes, several clean spatulas, and enough weighing boats for each student group by a calibrated balance in a well-ventilated area.
-
Place a bottle of 95% ethanol in a nearby hood. Then, make sure that the stopcocks for the columns fit securely but still turn easily.
-
Close the stopcocks after testing them and distribute the columns to the benchtop workspaces.
-
Make sure that each workspace has a lab stand or a scaffold and an appropriate clamp for the column being used.
-
Set out the following glassware and equipment at each student lab station (we suggest that students work in pairs):
5 50-mL beakers 1 100-mL beaker 1 5- or 10-mL graduated cylinder 2 50-mL graduated cylinders 2 Small powder funnels 1 Glass stirring rod 1 Roll of laboratory tape 1 Marking pen 1 Ruler 2 Pipette bulbs -
Lastly, place glass or cotton wool, at least one long, blunt-ended metal or wooden rod, and a box of Pasteur pipettes in the central area with the dye solution.
-