[chickensoup]

 i should probably know this but its driving me nuts. Say i have a cuvette with 0.4mg/ml of tryptophan and have to dilute it with 1/2 deionized water. how much do i need for this dilution? It says i need at least 2ml total volume per dilution.
Also, I have to make four additonal serial dilutions from the 1/2 dilution.

Keep in mind that (1/6) is one part of one thing and five of another, as opposed to 1:6 where its one part one thing and 6 parts of another to make a total of 7 units.