What is the primary use of a spectrophotometer in a laboratory setting?

The primary use of a spectrophotometer in a laboratory setting is to determine the concentration of substances such as proteins or DNA in a sample. This instrument works by passing light through a sample and measuring the intensity of light that is absorbed by the sample. The amount of light absorbed correlates with the concentration of the substance of interest, thanks to the principles of Beer-Lambert law, which states that absorbance is proportional to concentration.

In practical terms, when analyzing proteins or DNA, specific wavelengths of light are chosen that correspond to the maximal absorbance of those molecules. For example, nucleic acids absorb UV light at specific wavelengths, making spectrophotometry a quick and efficient method to quantify their concentrations in solution.

This method is frequently used in molecular biology, biochemistry, and various fields of research and clinical diagnostics, highlighting its significance in quantifying biological macromolecules essential for numerous experiments and studies.