How to weigh micrograms - (Oct/20/2009 )
I have 50 micrograms of a protein, of which I want to take 10 micrograms. My best scale is accurate to 0.01 milligram. I don't want to dilute everything at the same time since the expire time will shorten when diluting it and the protein is very expensive. Does anyone have any advice how I should do this?
is your balance "accurate" or "precise" to 0.01mg?
if it is "accurate" then you can weigh out 10ug with some confidence. if it is "precise" then i wouldn't consider weighing the protein.
is this a purchased protein? if so then it is usually accompanied by other solids of which the protein is a percentage of the total. in this case you can weigh out the protein and accompanying solids with confidence.
otherwise you will have to bite the bullet and dissolve the whole sample and pipette the amount you need.
Also, if it was bought, ask the company about ways to stabilise it after diluting it.