You are given a drug compound stock solution with a concentration of 5 mM. You n

Question

You are given a drug compound stock solution with a concentration of 5 mM. You need to prepare a dilution series in which you cover the range between approximately 200.0 pM and 1.00 pM of this compound in about dilution points (8 different concentrations). Describe how you make the dilutions. Consider using a diagram/cartoon for clarity or write your answer as steps 1. Do this, 2. Do that etc etc You have a protein stock with a concentration of 28 pM. The molecular weight of the protein is 56,000 Da Describe how you would use this stock solution to make 7.0 ml of a 25.0 pg/ml solution of this protein Write your answer as steps. 1. Do this. 2. Do that etc.

Explanation / Answer

1) For 8 different concentrations, we will dilte the solution as

Step 1. Take the original solution with concentration 5mM

Step 2. Now take 1mL from the same solution

Step 3. Add 24mL of water to it to make the solution 25mL

New concentration will be:

M1V1 = M2V2

5mM X 1mL = M2 X 25mL

M2 = 0.2mM

so new molarity = 200 micro Molar

Step 4. Again take 20mL of the above solution (200micro molar)

Step 5. Add 20mL of water in it. the new concentration will be 100micro molar

Step 6. Take 20mL of above solution ( 100 micro molar)

Step 7. Add 20mL of water in it to get new concetnration of 50 micro molar

Step 8. Take 10mL of above solution (50 micro molar)

Step9. Add 10mL of water in it to get solution of concentration 25 micro molar

Step 10. take 10mL of above soltuion and add 5mL of water in it to get solution of concentration = 25 X 10 / 15 = 16.67

Step 11. Take 10mL of above soltion and add 5mL of water in it to get soltion of concentration = 16.67 X 10 / 15 = 11.13

Step 12. Take 10mL of above soltion and add 5mL of water in it to get soltion of concentration = 11.11 X 10 / 15 = 7.4 micro molar

Step 13. Take 10mL of above soltion and add 5mL of water in it to get soltion of concentration = 7.4 X 10 / 15 = 4.9 micro molar

Ques 2)

Protein concentration = 28 micro molar

Molecular weight = 56000 Da

We need to prepare solution of concentration = 25microgram / mL with volume = 7mL

Step 1. Let us calculate the concentration of required solution in micro molar

Step2. 25micrograms = 446.3 pmoles / mL = 446.3nanomoles / L = 0.446 micromoles / L = 0.446 micro molar

Step 3 .

M1V1 = M2V2

M1 = 28 micromolar

V1 = ?

M2 = 0.446 micromolar

V2 = 7mL

so V1 = 0.446 X 7 / 28 = 0.111 mL

Step 4. so we will take 0.111mL of stock solution will dilte it to 7mL with water

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