Which aspect does spectrophotometric analysis focus on in wastewater?

Spectrophotometric analysis is a technique widely used in wastewater testing that primarily measures the concentration of specific compounds within a sample. This method operates on the principle that different substances absorb light at different wavelengths. By measuring the intensity of light absorbed by the sample at a specific wavelength, one can determine the amount of a particular substance present based on its absorbance characteristics.

This approach is particularly useful for evaluating parameters such as chemical oxygen demand (COD), biochemical oxygen demand (BOD), and various pollutants that may be dissolved in water, allowing for effective monitoring and compliance with environmental regulations.

In contrast, evaluating the size of particles or the presence of microorganisms focuses more on physical and microbiological aspects of the wastewater rather than the concentration of dissolved substances. While color changes can indicate the presence of certain contaminants, they do not provide direct quantitative data about concentration, which is central to spectrophotometric analysis. Thus, the focus on measuring concentration sets this method apart from the other options.