9: Try a biology example

It is exactly the same in the lab–try it yourself

John and Suzy want to measure the concentrations of a protein (Bovine Serum Albumin, BSA) in solution. After finding the proper wavelength (280nm), the ODs of 1 mg/mL, 2 mg/mL, 4 mg/mL, and 8 mg/mL BSA solutions were obtained. They then measured the ODs of two unknown BSA solutions. What were the concentrations of the protein solutions?

BSA concentration (mg/mL)

OD
(280 nm)

1

0.3

2

0.6

4

1.2

8

2.4

Unknown 1

0.7

Unknown 2

1.5

First, what is “e”?

So far, we know that e = 0.3 OD/mg/mL. Fitting that into our equation, we get

  OD = 0.3 c

Now that you have “e”, what are the concentrations of the two unknown protein samples? (Their ODs were 0.7 and 1.5).