What type of study deals with the quantitative analysis of electromagnetic spectra related to visible light?

Spectrophotometry is the correct answer as it refers to the technique used to measure the intensity of light absorbed by a sample at different wavelengths, specifically in the visible spectrum. This method involves quantifying how much light is absorbed by substances when light passes through a sample, providing important quantitative data about the concentration of the substances present.

The significance of spectrophotometry in biotechnology and many other fields lies in its ability to facilitate precise measurements. By producing a spectrum that shows absorption at different wavelengths, researchers can identify specific compounds and quantify their concentrations in solution. This technique is fundamental for many applications, including determining the concentration of DNA, proteins, or other biomolecules in a sample.

Other options such as chromatography primarily focus on separating components of a mixture rather than quantifying electromagnetic spectra. Assays are used to measure the presence or concentration of a substance but are not necessarily tied to the analysis of light spectra. Buffers are solutions that help maintain pH levels in biological experiments but do not pertain to the analysis of light. Thus, spectrophotometry stands out as the method specifically designed for the quantitative analysis of electromagnetic spectra in the visible light range.