Suppose you have a protein sample and its concentration is 10mg/ml. If you take 0.5 ml aliquot and make up to 3 ml. How many mg protein is present in ml of fraction?

Answer 1

The answer is fairly straight forward on one condition- and that is that the diluent allows for the protein to be totally and evenly soluble. If you start with a concentration of protein X at 10mg/ml (no matter what the starting volume is) and you take 0.5ml of that material - than you are now starting with 5mg (or 5mg in one half of a ml). However the concentration will be lower as you are putting 5mg into a total 3ml. This will now give you 1.5mg in 3ml. If you want to know how much is in every single ml of that solution than you simply divide by 3. You will have 0.5mg/ml in each ml.