TO MAKE WORKING SOLUTIONS (10 uM and 100 uM)
The problem is this: you have a stock solution of 0.1 M (100 mM).
How do you make a working solution of 100 uM?
Expressed in another way, you want to dilute your 0.1 M solution down to 0.0001 M (or 0.1 mM).

There are some equivalences here that are important:
1 M = 1,000 mM = 1,000,000 uM.
Therefore, 0.1 M = 100 mM = 100,000 uM.
And thus, 0.0001 M = 0.1 mM = 100 uM.

To go from 0.1 M down to 0.0001 M (which is from 100 mM down to 100 uM), you have to make a 1:1,000 dilution.

TO MAKE 1 LITER (1L = 1,000 mL) OF A 100 uM WORKING SOLUTION:
Measure 1 L of water into the large bottle.  Put a mark (use a permanent marker) on the side of the large bottle to indicate the fill level for 1 L of fluid.  Empty the large bottle, which you have just turned into a 1 L graduated bottle.

Measure 9 mL water into the graduated cylinder.  Leave the water in the cylinder.

Use an eyedropper or pipette to add 1 mL of the 0.1M STOCK solution to the graduated cylinder.  You will be adding STOCK solution until the total in the cylinder reaches the 10 mL line (9 + 1 = 10).

Pour the cylinder into the 1 L large container.  Rinse the cylinder into the 1 L container two or three times.  Then add sufficient water to bring the total fluid level up to 1 L.  Cap and shake.  Label this container: "100 MICROMOLAR (100 uM) WORKING SOLUTION".

TO MAKE 10 uM WORKING SOLUTION:
You need to make a 1:10 dilution of the 100 uM working solution.

Measure 9 mL water into the graduated cylinder.  Leave the water in the cylinder.

Use an eyedropper or pipette to add 1 mL of the 100 uM WORKING solution to the graduated cylinder.  You will be adding 100 uM WORKING solution until the total in the cylinder reaches the 10 mL line (9 + 1 = 10).

Pour the cylinder into a small bottle.  Cap and shake.  Slowly uncap the bottle, and pour the solution back into the graduated cylinder.  Repeat transfer from cylinder to bottle and back again three or four times.  Make the last transfer into the small bottle, and cap securely.

Label this container: "10 MICROMOLAR (10 uM) WORKING SOLUTION".

There is an easier alternative, if you are able to accurately measure 0.1 mL:

 stock (0.1 M) dilute to: 100 uM working: 0.1 mL 100 mL 10 uM working: 0.1 mL 1,000 mL

Return to Credits and Intro
TO MAKE COLCHICINE STOCK  SOLUTIONS
TO MAKE ORYZALIN STOCK  SOLUTIONS