What is a spectrophotometer used for in the laboratory?

A spectrophotometer is primarily used to determine the concentration of specific substances in a liquid by measuring the amount of light that a sample absorbs at a particular wavelength. The device operates on the principle that different substances absorb light differently. By passing light through a sample and measuring the intensity of light that emerges, the spectrophotometer can provide quantitative data about the concentration of the absorbing species in the solution.

This technique is valuable in various laboratory applications, such as determining the concentration of proteins, nucleic acids, and other biomolecules in biological samples. The relationship between absorbance and concentration is typically described by Beer's Law, which allows for the accurate calculation of concentration when the absorbance is known.

In contrast, measuring temperature changes, counting white blood cells, or examining cellular morphology involves separate techniques and instruments, such as thermometers, hemocytometers, or microscopes. These methods do not utilize the principles of light absorption and are not functions of a spectrophotometer.