What method is often used for quantifying specific light wavelengths absorbed by substances?

Spectrophotometry is a powerful technique commonly employed to quantify specific light wavelengths absorbed by various substances. This method relies on the principle that different compounds absorb light at characteristic wavelengths due to their molecular structure. By measuring the intensity of light before and after it passes through a sample, one can determine how much light has been absorbed by the substance.

This quantification is often expressed in terms of absorbance, which correlates with the concentration of the absorbing species in the solution. According to Beer-Lambert Law, there is a linear relationship between absorbance and concentration, allowing for accurate determinations. Spectrophotometry is widely used in various fields, including biochemistry, pharmaceuticals, and environmental science, to analyze the concentration of biomolecules, reactive intermediates, and pollutants.

In contrast, chromatography is a technique used for separating components of a mixture rather than quantifying light absorption. Activity and potency assays are methods that evaluate the biological effects or the strength of a substance, respectively, and do not focus specifically on measuring absorbance at specific wavelengths. Thus, spectrophotometry stands out as the method specifically geared towards quantifying light absorption by substances.