I have a stock solution of 20 uL which contains 4000 ng of cDNA.
My desired reaction for each PCR is 20 uL reaction and I need a total of 8 uL containing 10 ng of cDNA from my stock solution. What calculations/dilutions would need to be done to obtain that in a 5 uL pipetted from the initial 20 uL stock solution?
Vana Ali So you are saying your entire 20μL contains 4000 ng of cDNA.
That means you have 200 ng/μL (per microlitre).
So you want 10 ng total DNA in 8μL right? Therefore 10 in 8 is 10/8 = 1.25 ng/μL.
So, you will have to add 0.05 μL of your stock cDNA solution in 7.95 μL of nuclease free water.
I suggest you to calculate for more volume than for how much you want so that you can pipette entire 8 microlitre easily. (For example, for 10 μL; 0.06 μL of cDNA solution in 9.94 μL of nuclease free water).
I hope you understood how I calculated. For the volume addition and all, if you don't understand, I might suggest you to use an app for android phone in Play Store called 'Lab Hacks'. There you can make all your dilutions in a matter of seconds by giving your required input.
Cheers!
Hi Vana,
You may use the web tool to calculate
https://www.alfa-chemistry.com/solution-dilution-calculator.htm
- Badges
- Science topic