Question

Five ?L of a 10-to-1 dilution of a sample were added to 5mL of Bradford reagent. The absorbance at 595 nm was 0.78 and,according to a standard curve, corresponds to 0.015 mg of proteinon the x axis. What is the protein concentration of the original solution?

Answer 1

Answer:

0.03g/mL

Explanation:

Given parameters include:

Five μL of a 10-to-1 dilution of a sample; This implies the Volume of dilute sample is given as 5 μL

Dilution factor = 10-to-1

The absorbance at 595 nm was 0.78

Mass of the diluted sample = 0.015 mg

We need to first determine the concentration of the diluted sample which is required in calculating the protein concentration of the original solution.

So, to determine the concentration of the diluted sample, we have:

concentration of diluted sample = $\frac{mass}{volume}$

= $\frac{0.015 mg}{ 5 \alpha L}$   (where ∝ was use in place of μ in the expressed fraction)

= 0.003 mg/μL

The dilution of the sample is from 10-to-1 indicating that the original concentration is ten times higher; as such the protein concentration of the original solution can be calculated as:

protein concentration of the original solution = 10 × concentration of the diluted sample.

= 10  × 0.003 mg/μL

= 0.03 mg/μL

$= \frac{0.03*10^{-3g}}{10^{-3}mL}$

= 0.03g/mL

Hence, the protein concentration of the original solution is known to be  0.03g/mL