- Determine the final volume (Vf): How much to you want to make?
- Determine the dilution factor (d.f.). User either...
d.f. = Cs / Cf i.e. the ratio of starting concentration / final concentration:
d.f. = the fold concentration (e.g. 20x) of the starting material (if the final concentration is 1x)
- Calculate the starting volume (Vs): How much of the concentrated stock will you use?
Vs = Vf / d.f.
- Calculate the diluent volume (Vd): With how much water will you dilute the stock?
Vd = Vf - Vs
Example #1: You want to make up 1 mL of oligonucleotide N1 at a concentration of 2 µM using a stock of 50 µM using water as the diluent.
- Vf = 1000 µL
- d.f. = Cs / Cf = 50 / 2 = 25x
- Vs = Vf / d.f. = 1000 / 25 = 40 µL
- Vd = Vf - Vs = 1000 - 40 = 960 µL
- Thus add 40 µL of the N1 primer + 960 µL H2O.
Example #2: You want to make up 7 L of TAE buffer from a 20x stock using water as the diluent.
- Vf = 7000 mL
- d.f. = 20x
- Vs = Vf / d.f. = 7000 / 20 = 350 mL
- Vd = Vf - Vs = 7000 - 350 = 6650 mL
- Thus use 350 mL of 20x TAE + 6650 mL H2O.