How much of the stock solution do you need to add to make 1000 microliters of 1 picomolar plasmid DNA?
In a DNA cloning experiment, the plasmid DNA concentration for the transformation reaction is supposed to be 1 picomolar. A stock solution of 1 micromolar was ordered. How much of the stock solution do you need to add to make 1000 microliters of 1 picomolar plasmid DNA?
When solutions are diluted or
concentrated, the equality is:
Ms x Vs = M x V
where,
Ms = molarity of stock
Vs = volume of stock
M = new molarity
V = new volume
———————————-
For this problem,
M stock x V stock = M plasmid DNA x V plasmid DNA
Solving for V stock:
V stock = (M plasmid DNA x V plasmid DNA) / (M stock) ~(eq1)
where,
M stock = 1 micromolar = 1 µM = (1×10^-6 M)
M plasmid DNA = 1 picomolar = 1 pM = (1×10^-12 M)
V plasmid DNA = 1000 microliter = 1000 µL = 1000·(1×10^-6 L)
Substituting numbers into ~(eq1):
V stock = (1 pM x 1000 µL) / (1 µM)
canelling-out/dividing µ
= (1 pM x 1000 L) / (1 M)
canelling-out/dividing M
= 1 p x 1000 L
= 1000 pL
Answer:
*** 1000 pL ***