The Beer Lambert Law

Introduction When white light passes through the prism, a continuous color spectrum is formed in the visible region of the electromagnetic spectrum. The color of the compound is a mixture of wavelengths that are transmitted through the sample without being absorbed. Beer-Lambert's law applies to determine the concentration of coloring matter in solution. The colorant concentration is proportional to its absorbance at that wavelength. A = εbc, A is the absorbance, ε is the molar absorbance, b is the length of the opening (cm), c is the concentration of the coloring substance and is the line of y = mx + b (Patterson 2).

The overall idea of ​​determination of compound concentration by spectrophotometry is based on Beer's law. Beer's law or Bill-Lambert's law is the relationship between absorbance and concentration of a sample. The application of Beer's law can determine the peak of solute absorption and can be used to plot absorption spectra on so-called beer's law diagrams or curves. The procedure for finding the absorption spectrum of cobalt chloride uses Beer's law and spectrophotometric method. A spectrophotometer dedicated to this experiment is spectronic 20. Like other experiments, experiments require control. In this case, use distilled water as a control. A cuvette is a small plastic container used in equipment to hold a solution filled with distilled water. Next, put the cuvette in the sample holder. At this point the machine is set to 400 nm and the transmittance is 100% at this wavelength.

UV spectrum follows Beer-Lambert's law. The law states that whenever a monochromatic beam passes through a solution with an absorbing material the rate of decrease in radiation intensity with the thickness of the absorbing solution is actually proportional to solution concentration and incident radiation. It can also be used to detect the degree of conjugation in the polyene. As double bonds increase, absorption is released to longer wavelengths. In addition, UV spectra can be used to identify unknown compounds. The spectrum of the unknown compound is compared with the spectrum of the reference compound. If the two spectra match, we identify the unknown compound successfully.