Answer to Question #288692 in General Chemistry for Mika

Question

I have a stock of 3.15mg/ml and I need to make a solution with water total volume of 200 ul with concentration of 200 ng/ml. I get serial dilution math but how do I make this pipettable volume?

Answer 1

Given, M₁ =3.15$\frac{mg}{mL}$  , V₁ = ? 

M₂ =200$\frac{mg}{mL}$  , V₂ = 200$\mu L$

M₁ in ng per mL

We know, 1 mg = 1.0 x 10⁶ ng

So, 3.15 mg = 3.15 x 10⁶ ng

Dilution law,   

M1V1=M2V2

V1=0.0127$\mu L$

We need to take 0.0127  of 3.15$\frac{mg}{mL}$   and diluted to 200$\mu L$  to prepare  of 200$\frac{mg}{mL}$of 200$\mu L$