Quantify proteins in solution using spectrophotometric absorbance (A280) or the Warburg-Christian correction method.
Spectrophotometry
Protein Quantification
0.750mg/mL
Protein Concentration
In 10 μL7.5μg
A260/A2800.50ratio
Beer-Lambert Projection
About this calculator
Overview
Protein quantification by absorbance at 280 nm is a non-destructive method based on the aromatic amino acids (Trp, Tyr) and Disulfide bonds present in the sample.
💡
Pro Tips
A280 Method: Best for purified proteins with a known extinction coefficient.
Warburg-Christian: Best when nucleic acid contamination is suspected (using A260/A280 ratio).
Most accurate results are obtained between 0.1 and 1.5 Absorbance units.
Always zero the spectrophotometer with the appropriate buffer blank.
!
Fun Facts
"A280 relies on Tryptophan and Tyrosine residues; proteins lacking these cannot be measured this way."
"A pure protein typically has an A260/A280 ratio > 1.8; lower values suggest DNA/RNA contamination."
"The method is non-destructive, allowing sample recovery."
