absorbansmätning

Absorbansmätning, or absorbance measurement, is a fundamental technique in analytical chemistry and various scientific fields used to quantify the amount of light absorbed by a sample. This method relies on the principle that substances absorb light at specific wavelengths, and the degree of absorption is directly proportional to the concentration of the substance.

The most common instrument for absorbance measurement is a spectrophotometer. A spectrophotometer works by passing a beam of light of a specific wavelength through a sample contained in a cuvette. A detector then measures the intensity of the light that has passed through the sample. The difference between the initial intensity of the light and the intensity after passing through the sample is used to calculate the absorbance.

Absorbance is typically reported on a logarithmic scale, often following the Beer-Lambert law, which states that absorbance is directly proportional to the path length of the light through the sample and the molar absorptivity of the substance, as well as the concentration of the substance. Mathematically, this is expressed as A = εbc, where A is absorbance, ε is molar absorptivity, b is path length, and c is concentration.

Absorbance measurements are widely used for a variety of applications, including determining the concentration of unknown solutions, identifying and characterizing chemical compounds, monitoring chemical reactions, and in fields like biochemistry for protein quantification and in environmental science for water quality analysis. The simplicity and accuracy of the technique make it an indispensable tool in many laboratories.