Home
Back
Beer-Lambert Law:
| From: | To: |
The Beer-Lambert Law describes the relationship between absorbance and the properties of the material through which light is passing. It states that absorbance is directly proportional to the concentration of the absorbing species and the path length of the light through the material.
The calculator uses the Beer-Lambert Law equation:
Where:
Explanation: The equation calculates the concentration of a solution based on how much light it absorbs, the substance's inherent ability to absorb light, and the distance the light travels through the solution.
Details: Accurate concentration determination is crucial for chemical analysis, pharmaceutical preparations, environmental monitoring, and various scientific research applications where precise measurements are essential.
Tips: Enter absorbance (unitless), molar absorptivity in L/mol cm, and path length in cm. All values must be positive numbers greater than zero for accurate calculation.
Q1: What is molar absorptivity?
A: Molar absorptivity (ε) is a measure of how strongly a chemical species absorbs light at a particular wavelength. It's a constant for each substance at a specific wavelength.
Q2: What are typical absorbance values?
A: Absorbance values typically range from 0 to 2 for accurate measurements. Values above 2 may indicate the solution is too concentrated and should be diluted.
Q3: Why is path length important?
A: Path length directly affects absorbance - longer path lengths result in greater absorbance. Standard cuvettes typically have a 1 cm path length.
Q4: What are the limitations of Beer's Law?
A: The law assumes monochromatic light, dilute solutions, and that absorbance is solely due to the analyte of interest without chemical interactions or scattering.
Q5: Can this calculator be used for any wavelength?
A: Yes, but molar absorptivity values are wavelength-specific, so you must use the ε value corresponding to the wavelength at which absorbance was measured.