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Spectrophotometry is an analytical method of measuring the amount of visible or ultra-violet light absorbed or transmitted by a substance in solution. Concentrations of various substances can also be determined using spectrophotometry and it is a commonly used technique that detects amounts of drugs,proteins and DNA. The amount of light absorbed is proportional to the concentration of the solute; it is often then possible to construct a standard curve to figure out unknown concentrations. This method has been adopted and used in the study of biochemistry, physics, chemical engineering and more.

All substances in solution absorb light of one wavelength and transmit light of another wavelengths. Absorbance is a characteristic of a substance just like melting point, boiling point, density and solubility. There are two types of spectrophotometers. UV-Visible uses light which ranges from 185 to 700 nm and IR spectrophotometers which uses light with a range from 700 to 1500 nm[1].


  1. Spectrophotometry. Chemistry Libretexts.[cited 3 December 2017].Available from:https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Kinetics/Reaction_Rates/Experimental_Determination_of_Kinetcs/Spectrophotometry
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