You have a protein solution with unknown concentration. Its extinction coefficient at 280 nm is...
Question:
You have a protein solution with unknown concentration. Its extinction coefficient at 280 nm is 23,000 M{eq}^{-1} {/eq}cm{eq}^{-1} {/eq}. You measure the absorption at 280 nm in a 1 cm path-length cuvette and get 0.3. What is the protein concentration? Explain your answer.
Beer-Lambert's Law:
Beer-Lambert's law relates the absorbance of a solution with its concentration. It says that the absorbance is directly proportional to the molar concentration of the solution and thus, the graph between A and c is a straight-line and hence can be used to find the concentration of an unknown solution. Mathematical expression for the relation is:
{eq}A=\epsilon bc {/eq}
where b is the path length that light travels = length of the cuvette
c = molar concentration of the solution
{eq}\epsilon {/eq} is the molar absorptivity
A is the absorbance of the solution
Although the law is valid only for very dilute solutions
Answer and Explanation:
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How to Use Spectrophotometry to Understand Beer's Law
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Chapter 4 / Lesson 9
35K
Understand the Beer-Lambert Law equation and Beer's law units. Explore how Beer's Law is used in spectrophotometry and solve problems involving Beer's Law example.
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