Question

you have a glucose stock solution that has a concentration of a 4 mg/ml. How would you make a solution containing 1 mg of glucose in a 1 ml total volume?

Answer 1

Consider you have 10 ml of 4mg/ml glucose stock solution. If now total glucose in mg will be 40 mg in 10 ml solution. Now you make up the volume of this 10ml to 40 ml. Now, 40 ml solution will have 40 mg glucose. This will be 1 mg/ml.

So, if you are having V1 volume of 4mg/ml stock solution, add 3*V1 ml of water which gives 4*V1 volume of solution that has 1mg/ml.