1. What is the Beer-Lambert Law?

The Beer-Lambert Law relates the attenuation of light to the properties of the material through which the light is traveling. It is commonly used in chemistry to measure the concentration of chemical solutions.

2. How Does the Calculator Work?

The calculator uses the Beer-Lambert Law:

Where:

• \( C \) — Concentration (mol/L)
• \( A \) — Absorbance (dimensionless)
• \( \varepsilon \) — Molar extinction coefficient (L/mol/cm)
• \( l \) — Path length (cm)

Explanation: The law states that absorbance is directly proportional to the concentration of the absorbing species and the path length.

3. Importance of Concentration Calculation

Details: Accurate concentration measurement is crucial for quantitative analysis in chemistry, biochemistry, and molecular biology experiments.

4. Using the Calculator

Tips: Enter absorbance (typically between 0.1-1.0 for best accuracy), molar extinction coefficient (specific to your compound), and path length (usually 1 cm for standard cuvettes).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical molar extinction coefficient value?
A: It varies greatly by compound. For example, NADH at 340 nm has ε ≈ 6220 L/mol/cm, while proteins at 280 nm have ε ≈ 10,000-50,000 L/mol/cm.

Q2: Why is absorbance dimensionless?
A: Absorbance is a logarithmic ratio of light intensities (I₀/I), making it unitless.

Q3: What is the ideal absorbance range for accurate measurements?
A: 0.1-1.0 absorbance units. Values above 1 may be less accurate due to stray light effects.

Q4: Can I use this for mixtures?
A: For mixtures, you need additional information or measurements at different wavelengths to resolve individual concentrations.

Q5: How does path length affect the measurement?
A: Longer path lengths increase sensitivity but may require sample dilution to keep absorbance in the optimal range.