Question

How would you do four fold dilutions for ELISA given that each well must have 50ul of the diluted sample. The first dilution is 1:100 which would be 49.5 ul of buffer and 0.5ul of sample. How would I go about doing serial dilutions to get 1:400, 1:1600, 1/3200 etc? Sorry for the scarce information. Thanks for the help.

Answer 1

In order to obtain the desired dilution, following steps can be taken:

Dilution 1:400

Dilute 1ul of sample with total of 400-1 = 399 ul of sample buffer to get 1/4+396 or 1:400 dilution.

Dilution 1:1600

Dilute the 1:400 dilution to 4 times i.e. by taking one part of the dilute sample and simply adding 4 parts of sample buffer to it. This will give a final 1/400*4 or 1:1600 dilution.

Diltuion 1:3200

Dilute the 1:1600 dilution to 2 times i.e. by taking one part of the dilute sample and simply adding 4 parts of sample buffer to it. This will give a final 1/1600*2 or 1:3200 dilution.