titrations - (Dec/08/2008 )

am wanting to titre some antibodies to work out the best concentration to use. The stock concentration is 2mg/ml. im wanting to do a dilution of my antibodies from 10ug to 5ug to 2ug to 1ug to 0.1ug .
how is the best way to do this when i need approx 200ul volume for each tube

Hey Minnie mouse

I dont have a lot of sample to spare so was only wanting to do 5 dilutions if possible. Ive never done titrations before so am unsure as to how to set it up?

If my stock concentration is 0.2mg/ml (not 2mg/ml) how do i start my titration off. I have about 200ul of sample to add to each tube for my titrations?

you got more than enough amount of sample.

stock concentration 0.2mg/ml
you got 200ul
therefore you have 0.2mg/ml x 200ul = 0.04mg =40ug

starting titration is 10ug in 200ul

I would be easier to do 1 in 2 dilution to avoid mistake

Tube 1: 20ug sample in 400ul (buffer/solution eg. PBS, water)
Tube 2-7: Put 200ul of buffer/solution into each tube

Method:
1. put 100ul of stock into Tube 1 that contains 300ul of buffer/solution
2. mix Tube 1
2. Transfer 200ul of Tube 1 into Tube 2 that contains 200ul of buffer
3. mix Tube 2
4. Transfer 200ul of Tube 2 into Tube 3 that contains 200ul of buffer
5. mix Tube 3
6 Transfer 200ul of Tube 3 into Tube 4 that contains 200ul of buffer
and so on.

The final amount of sample:
Tube 1: 10ug
Tube 2: 5ug
Tube 3: 2.5ug
Tube 4: 1.25ug
Tube 5: 0.625ug
Tube 6: 0.3125ug
Tube 7: 0.15625ug
Tube 8: 0.078125ug

it doesn't save you much samples if you decided to do 5 dilution.

Hope this may help.

I think you have posted in the incorrect forum. I have moved this post to Immunology Forum