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Beer-Lambert Law:
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The Beer-Lambert Law describes the relationship between the concentration of a solution and its absorbance of light at a specific wavelength. It states that absorbance is directly proportional to the concentration of the absorbing species and the path length of the light through the solution.
The calculator uses the Beer-Lambert Law equation:
Where:
Explanation: The equation calculates the concentration of a solution by dividing the measured absorbance by the product of molar absorptivity and path length.
Details: Accurate concentration determination is crucial for quantitative analysis in chemistry, biochemistry, pharmaceuticals, and environmental testing. It allows researchers to determine the amount of a specific substance in a solution.
Tips: Enter absorbance (unitless), molar absorptivity in M⁻¹ cm⁻¹, and path length in cm. All values must be positive numbers. The calculator will provide concentration in molarity (M).
Q1: What is the valid range for absorbance values?
A: The Beer-Lambert Law is most accurate for absorbance values between 0.1 and 1.0. Values outside this range may suffer from significant measurement errors.
Q2: How do I determine the molar absorptivity (ε)?
A: Molar absorptivity is typically determined experimentally by measuring absorbance of solutions with known concentrations and calculating ε from the slope of the calibration curve.
Q3: What is the standard path length used in spectrophotometry?
A: The standard path length for most cuvettes is 1.0 cm, though other sizes (0.1 cm, 1.5 cm, etc.) are also available and must be specified.
Q4: Does the Beer-Lambert Law work for all concentrations?
A: The law assumes ideal behavior and works best for dilute solutions. At high concentrations, deviations may occur due to molecular interactions.
Q5: Can this calculator be used for mixtures?
A: For mixtures with multiple absorbing species, more complex calculations involving multiple wavelengths and simultaneous equations are required.