1. The problem statement, all variables and given/known data I need to calculate molar extinction coefficient for Albumin at 280nm. 2. Relevant equations A=ε*c*L ε=A/(c*L) But since L=constant, I can just say ε=A/c 3. The attempt at a solution The given molecular mass of albumin is 66,5kDa, which equals 66500g/mol. I do understand that I can find c (concentration) via the molecular mass. What I don't understand is how can I find ε if I still have another unknown, which in this case happens to be A. So: ε(unknown)=A(unknown)/c(known). Have I missed something really simple and overthinking this for myself? How can I find Absorbance?