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Beer-Lambert Law:
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The Beer-Lambert Law relates the absorption of light to the properties of the material through which the light is traveling. It states that the concentration of a substance is directly proportional to the absorbance of a solution and inversely proportional to the path length and molar extinction coefficient.
The calculator uses the Beer-Lambert Law equation:
Where:
Explanation: The equation shows that concentration can be determined by measuring how much light a solution absorbs, knowing the substance's specific absorption characteristics and the distance the light travels through the solution.
Details: This calculation is fundamental in analytical chemistry, biochemistry, and molecular biology for determining unknown concentrations of solutions using spectrophotometry.
Tips: Enter absorbance (typically between 0.1-1.0 for best accuracy), the substance's molar extinction coefficient (found in literature), and path length (usually 1 cm for standard cuvettes).
Q1: What is the ideal absorbance range for accurate measurements?
A: The most accurate measurements are typically obtained between 0.1 and 1.0 absorbance units.
Q2: Where can I find molar extinction coefficients?
A: These are substance-specific and can be found in chemical literature, databases, or published papers for known compounds.
Q3: Why is path length important?
A: Path length affects how much light is absorbed - longer path lengths mean more absorption at the same concentration.
Q4: Does this work for all wavelengths?
A: You must use the extinction coefficient that corresponds to the wavelength at which you measured the absorbance.
Q5: What if my solution is too concentrated?
A: For high concentrations, dilute the sample and multiply the result by the dilution factor to get the original concentration.