dilution - diluting (May/30/2009 )

Could someone please explain how to complete the following dilution calculation:

I have 100ug/ml NGF (nerve growth factor) and I need my final volume to be 50ng/ml. The total volume is 200 mls. Essentially, I need to know how much NGF (100ug/ml) to add to 200 mls growth media to make 50 ng/ml.

If someone could explain this in detail that would be greatly appreciated.

iceman08 on May 30 2009, 12:53 PM said:

Hi,
the formul u have to follow is V1*N1 = V2 * N2

V1 = the volume u need
N1 = stock concentration 100ug/ml otherwise 100,000ng(since ur desired concentration is in ng)

V2 = ur final volume, 200ml
N2 = desired concentration 50ng

therefore, V1 = V2*N2/N1

= 200 * 50ng / 100,000ng
= 0.1ml or 100ul...

So u need 100ul of ur stock into 200ml of ur growth media, although u have to discard 100ul of the growth media prior to adding ur NGF.

Please recheck the calculations with someone else too.. Good luck... Hope it helps...