prepare 1:10 serial dilution of 300mg/ml stock in a total volume of 3ml of concentrations 150,15,1.5,0.15 mg/m

Question

how would you prepare 1:10 serial dilution of concentrated 300mg/ml stock in a total volume of 3 ml with concentrations 150mg/ml , 15mglml ,1.5 mg/ml and 0.15mg/ml ? what are the steps ?Can you explain hoew its working ?how many ml I need to transfer from stock ?What is dilution factor?

Answer 1

You just need to use the formula
M1*V1= M2*V2 => V1= (M2/M1)*V2
where M1 is the concentration of the stock solution
V1 the volume of stock solution that you need to prepare V2 volume of your dilute solution that will have concentration M2.

Usually M is expressed in mole/lt and V in liters.
However, with this formula the conversion factors are simplified and thus you can use directly the mg/ml values for concentration and ml for volume.

So you have V2= 3ml, M1=300 mg/ml and you need to calculate V1 for different M2. The dilution factor is M2/M1. So for

a)150 mg/ml
V1= (150/300)*3 =1.5 ml, dilution factor 150/300=1:2

b)15 mg/ml
V1= (15/300)*3 =0.15 ml, dilution factor 15/300=1:20

c)1.5 mg/ml
V1= (150/300)*3 =0.015 ml, dilution factor 1.5/300=1:200

d)0.15 mg/ml
V1= (0.15/300)*3 =0.0015 ml, dilution factor 0.15/300=1:2000

Preparing solutions:
When you are dealing with moderats/large volumes you use suitable volumetric cylinders (or volumetric flasks for higher accuracy), dissolve your compound in a bit of solvent, and add solvent up to the desired volume.
For very small volumes (<2ml) you have to do the approximation that you add V1 ml of your stock to V2-V1 ml of your solvent.

In your case you can use a volumetric cylinder (the smallest you can find in your lab, e.g. a 10ml cylinder)
You can simply add the amount of stock, fill-up to 3ml with water (assuming that is your solvent and mix.
For very small volume use a micro-pipette and pipette the stock solution in a it of water. You should note that the smaller volumes of stock solution you use the higher the error in the final concentration. Since you are making a dilution series, you could use the solution you make at each step as a stock for the next step. then you have always a dilution factor of 1:10 and you would need 0.3 ml of that solution. (For volumes <1ml use a micropipette). However this would mean that you are left with only 2.7ml of the first 3 solutions of your series. If you need the whole 3ml, just prepare a bit more (e.g. 3.5ml) using the formula I showed you.

Answer 2

How To Prepare Serial Dilutions

Answer 3

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