Which type of assay is commonly used to analyze the concentration of substances in solutions?

Spectrophotometry is a widely utilized method for quantifying the concentration of substances in solutions. This technique relies on measuring the amount of light absorbed by a sample at specific wavelengths. When a beam of light passes through a solution, certain wavelengths are absorbed by the solute molecules, and the degree of absorption is directly proportional to the concentration of the substance in accordance with Beer-Lambert law.

This method is valued for its sensitivity and ability to provide real-time results, making it suitable for various applications in biotechnology, chemistry, and environmental science. By selecting the appropriate wavelength for the substance being measured, researchers can achieve accurate concentration assessments.

Other types of assays mentioned serve different purposes. Potency assays typically evaluate the strength or effectiveness of a biological or chemical substance rather than how much of it is present. Activity assays measure the functional activity of a substance, like enzyme activity, rather than its concentration. Buffer assays, while important in maintaining pH levels in solutions, do not focus on quantifying the concentration of substances. Thus, spectrophotometry stands out as the method specifically designed for analyzing concentration in solutions.