Two figures in, a clear answer out. The protein concentration calculator uses absorbance at λmax, dilution factor, extinction coefficient, molecular weight and pathlength to produce concentration, applying the standard relationship for this problem in the order the calculation actually needs it.
What Is the Protein Concentration Calculator?
The protein concentration calculator works out concentration from absorbance at λmax, dilution factor, extinction coefficient, molecular weight and pathlength.
Biological relationships are usually approximations rather than exact laws, so the output is best treated as an estimate with a sensible range around it.
How the Protein Concentration Calculation Works
The calculation applies the relationship as published, step by step, so each intermediate value can be checked against the underlying theory.
Keep the units consistent throughout. Mixing a percentage with a proportion is the single most common source of an answer that is out by a factor of a hundred.
Assumptions Worth Knowing
Any relationship used here assumes a constant rate, a representative sample, or a stable population. Real populations rarely meet those conditions for long, so treat the answer as a guide.
Where the inputs are field measurements, a single misread value can shift the result noticeably. Measure carefully and record what you used.
A Worked Example
Working through an example, with absorbance at λmax set to 10, dilution factor set to 5, extinction coefficient set to 2, the calculator returns concentration of 250. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out concentration?
Enter absorbance at λmax, dilution factor, extinction coefficient, molecular weight and pathlength. The calculator then works through the relationship and reports concentration.
What does the protein concentration actually calculate?
It takes absorbance at λmax, dilution factor, extinction coefficient, molecular weight and pathlength and converts them into concentration using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter absorbance at λmax?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.
Is the answer exact?
It is as exact as the formula and the inputs allow. The method itself is the standard one for this problem, so the only sources of error are the figures you enter and the precision you ask for.