Expressing concentration in units of μg/mL or mg/mL are common in biochemistry, where accurate molecular weights of biomolecules are not always known. The plot below is the standard curve of a Bradford assay, a colorimetric method used to determine the concentration of protein. Assume you have 5.00 mL of a protein-containing solution. You take 0.0500 mL of your protein solution, add 0.950 mL of Bradford reagent, and measure the absorbance of the mixture. If the mixture has an absorbance of 0.546, what concentration of protein is present in your original solution?
I thought that I was supposed to use the equation given by the line of best fit (y=0.0119x), but that answer was incorrect (45.9M). Please help if you can! Thank you!
Oh! I forgot to include the r^2 value (if that is needed)
r^2=.9917
Nevermind :)
I figured it out!
Thank you though!
To determine the concentration of protein in your original solution, you need to use the equation of the standard curve, which relates the absorbance (y) to the protein concentration (x). In your case, the equation of the standard curve is y = 0.0119x.
Given that the absorbance of your mixture is 0.546, you need to substitute this value for y in the equation and solve for x, which represents the protein concentration.
0.546 = 0.0119x
To solve for x, divide both sides of the equation by 0.0119:
x = 0.546 / 0.0119
Using a calculator, this gives you:
x ≈ 45.8 mg/mL
So, the concentration of protein in your original solution is approximately 45.8 mg/mL.