Spectrophotometry is a quantitative measurement of a material’s absorption/transmission or reflection as a function of wavelength. Although it is called UV-Vis, the wavelength range commonly used ranges from 190 nm to 1,100 nm in the near-infrared. Using a spectrophotometer and taking absorption/transmission measurements, we can determine the amount (or concentration) of a known chemical by studying the number of photons (light intensity) that reach the detector. The more a material absorbs light at a given wavelength, the higher the concentration of the known substance.
