Extinction Coefficient Calculator
What is the Extinction Coefficient?
The extinction coefficient (ε) is a measure of how strongly a chemical species absorbs light at a given wavelength. It is used in the Beer-Lambert Law, which relates absorbance (A), concentration (c), and path length (l):
A = ε × c × l
This calculator helps you determine ε when you know the absorbance, concentration, and path length.
Frequently Asked Questions (FAQ)
What is the Beer-Lambert Law?
The Beer-Lambert Law states that the absorbance (A) of light by a substance is proportional to its concentration (c) and the path length (l) of the light through the substance. The formula is: A = ε × c × l.
How do I convert mg/mL to mol/L?
To convert mg/mL to mol/L, divide the concentration in mg/mL by the molecular weight of the substance (in g/mol). For example, if the molecular weight is 100 g/mol, 1 mg/mL = 0.01 mol/L.
What units should I use for path length?
Path length should be entered in centimeters (cm). If your measurement is in millimeters (mm) or meters (m), you can use the dropdown menu to convert it automatically.
Why is my result negative?
A negative result may occur if the inputs are incorrect or if the absorbance value is less than zero. Ensure all inputs are positive and valid.