dilutions - (Dec/12/2008 )

I need help.!I'm need to run a 3 microliters in the gel lanes and I wanted to know how to go about figuring out what dilutions to use. For instance one the concentrations is 4.75, how would I figure out about going to find out the dilution to use.

What is the unit for the concentration "4.75"?

and how much do you want to put in each lane (mass, not volume).