A protein solution (0.3ml) is diluted with 0.9ml water. 0.5ml is taken and reacted with 4.5ml of reagent and the resulting colour allowed to develop. The Abs at 540nm was 0.18 in a 1cm cuvette. A standard protein solution (0.5ml containing 2mg) gave an absorbance reading of 0.12 when reacted in the same way. How much protein would you have in 100ml of the undiluted original sample?

Answer 1

Absorbance of 2 mg std = 0.12
Absorbance of unk = 0.18 so
2 mg x (0.18/0.12) = 3 mg protein in the measured sample. That came from the 1.2 mL diluted sample. The amount in that was
3 mg x (1.2/0.5) = 7.2 mg in the 1.2 mL dilution. In the initial 0.3 mL sample there is 7.2 x (0.3/1.2) = 1.8. In 100 mL there will be
1.8 x (100/0.3) = ?

Answer 2

I don't know