Question

Determine the quantity of unknown protein that has an absorbance of 0.308 when a blank has an absorbance of 0.072. the previously determined calibration curve has the form of a straight line with the equation a = 0.0182 × x 0.007, where a is the corrected absorbance and x is quantity of protein in units of μg.

Answer 1

If the calibration curve is a straight line, it must follow the general form, y=mx+b. Thus, the equation must be: A = 0.0182x + 0.007. The corrected absorbance is:

Corrected Absorbance = 0.308 - 0.072 = 0.236
Substitute this to the formula to find x.
0.236 = 0.0182x + 0.007
Solving for x,
x = 12.58

Thus, the concentration of the protein at this absorbance is 12.58 μg.