## Calculations help

**Moderators:** honeev, Leonid, amiradm, BioTeam

### Calculations help

Hi i was wondering if you can help me i have a total volume of 400ul. I have a reagent that is 100ng/ml in 20ug/ml stock. I was wondering what is the volume of the reagent i need to add to the 400ul. Can you also show me the calculations

use the simplest formula ever c1V1 = c2V2

the stock is 20 ug/ml and final conc. should be 100 ng/ml, right? So, c1 = 100 ng/ml; V1 = 400 ul; c2 = 20 ug/ml and V2 you calculate

Otherwise you can think, that you need to dilute it 20 000/100 = 200-times, so the volume must be 200-times smaller i.e. 400/200 = 2 ul

the stock is 20 ug/ml and final conc. should be 100 ng/ml, right? So, c1 = 100 ng/ml; V1 = 400 ul; c2 = 20 ug/ml and V2 you calculate

Otherwise you can think, that you need to dilute it 20 000/100 = 200-times, so the volume must be 200-times smaller i.e. 400/200 = 2 ul

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*Cis*or*trans*? That's what matters.### Re:

RAZriz wrote:I have a reagent that is in PBS at 500x (1mg/ul) I need to know how much i need to add to a 50ml solution so the concentration would be 2ug/ml

50/500= ? That is what 500x mean, divide your final volume by the concentration factor (here 500) and you know how much to use.

Patrick

Science has proof without any certainty. Creationists have certainty without

any proof. (Ashley Montague)

Science has proof without any certainty. Creationists have certainty without

any proof. (Ashley Montague)

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