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Protein Concentration Formula:
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Protein concentration calculation from absorbance is a common laboratory technique that uses spectrophotometry to determine the concentration of protein in a solution. This method relies on the Beer-Lambert law and requires a standard curve for accurate quantification.
The calculator uses the formula:
Where:
Explanation: The standard slope is determined by measuring the absorbance of known protein concentrations and calculating the slope of the resulting standard curve.
Details: Accurate protein quantification is essential for various biological and biochemical experiments, including enzyme kinetics, protein purification, Western blotting, and many other applications where precise protein concentrations are critical.
Tips: Enter the measured absorbance value and the standard slope obtained from your protein standard curve. Ensure both values are positive numbers with absorbance typically between 0.1-1.0 for accurate measurements.
Q1: What is the optimal absorbance range for accurate measurements?
A: The optimal range is typically between 0.1-1.0 absorbance units. Values outside this range may be less accurate due to instrument limitations.
Q2: How do I determine the standard slope?
A: The standard slope is determined by measuring absorbance of known protein concentrations and calculating the slope of the line in a plot of absorbance vs. concentration.
Q3: Which protein assay methods use this calculation?
A: This calculation is commonly used with Bradford, Lowry, and BCA assays, though each may have slightly different standard curves.
Q4: Why might my calculated concentration be inaccurate?
A: Inaccuracies can result from improper standard curve preparation, interfering substances in the sample, or measurements outside the linear range of the assay.
Q5: Should samples be diluted if absorbance is too high?
A: Yes, samples with absorbance above 1.0 should be diluted and re-measured to ensure accuracy, then multiplied by the dilution factor.