# Solution Preparation - (May/03/2007 )

Hi,

So my PI asked me to make up stock solutions for a project and I'm a bit confused. He told me to make the stock solutions up at 1000x in DMEM. My question is that if the final concentration is supposed to be 2g/L am I supposed to make up a solution that is 2000g/L because that seems like alot of substance to weigh out? Also, how much of the stock solution should I make? Similarily, what should I do if the final concentration is supposed to be 0.025mg/L?

Thanks for your help, I'm new at this stuff.

Hi

I don't know of may chemicals that will dissolve at 2000 g/L. Perhaps the stock is supposed to be 2 g/L. What solution are you trying to make? Also check the protocols pages, there are a lot of recipes for making a huge range of solutions on there.

Bob

final conc.= **2g/L**=2000mg/L=2000mg/1000ml=**2mg/ml**

stock--> 2000mg/L

m1v1=m2v2

2000mg X v1=0.025mg X 1000ml

v1=0.0125ml from stock

If the final concentration is supposed to be 0.025mg/L then a 1000x solution is 25mg/L. That's basically nothing!

Perhaps you mean 0.025g/L in which case a 1000x solution is 25g/L which is perfectly reasonable.

2000g/L is, as far as I know, impossible. I'd like to hear of any examples otherwise!

yes, 2000g is really impossible

Thanks for the input.

I do mean 2g/L for a final concentration, so what should the stock concentration be made up as if my PI wants the dilution to be 1000x? This a componet of for cell culture media.