spectrophotometery essays

spectrophotometery essays The purpose of this lab experiment is to understand the uses of spectrophotometry. This experiment concentrates on the uses of the spectrophotometer, and using this instrument to specifically determine the absorption spectrum of a cobalt chloride solution, a galactose solution, and to determine an unknown concentration of a galactose solution. Modern biologists frequently use the measurement of light absorption to determine concentration of chemicals. The technique is called spectrophotometry. However, why is light absorbed? Light may be simply scattered by particles, but this is extremely important to the measurement of truly absorbed light. Light is the part of electromagnetic radiation to which the human eye is sensitive. Light is energy, and when absorbed by a chemical it results in a change in energy levels of the chemical. The energy of light depends on its wavelengths. Longer wavelengths, such as infrared, have less energy than shorter wavelengths, such as ultraviolet. A molecule will absorb light energy when a wavelength exactly matches the energy difference between two energy states of the molecule. A spectrophotometer makes use of the transmission of light through a specific solution to determine the concentration of a solute within a solution. It is based on a simple design of passing light of a known wavelength through a sample and measuring the amount of light energy that is transmitted. The design of a single beam spectrophotometer involves a light source, a prism, a sample holder, and a photocell. Connected to each are the appropriate electrical or mechanical to control the illuminating intensity, the wavelengths, and for conversion of energy received to readable data that can be recorded, which is known as a voltage fluctuation. This voltage fluctuation is displayed digitally and recorded for further analysis. The whole idea of spectrophotometery determining the concentration of a compound is ba...