The colorimeter is an instrument that allows for the measurement of light and its intensity to match colour as it is perceived by the human eye. The colorimeter compares the measured colour against the standard colours with the color spaces.
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What is Colorimeter?
Colorimetry is one of the methods of spectro analytical methods. The variation of the color of a solution with change in concentration of some solute component in the solution, forms the basis of colorimetry.
The colour is either the inherent colour of the constituent itself or due to the formation of a coloured species by the addition of a suitable reagent. The intensity of the colour can then be compared with that obtained by treating a known amount of the chemical substance in the same manner.
General Principles of Colorimeter
A colorimeter May be used to measure the concentration of a chemical in a solution if the chemical imparts a characteristic color to the solution.
- The colorimeter optical system isolates a narrow waveband of light at a selected absorption peak for the chemical that is measured.
- The intensity of the transmitted light at the absorption wavelength is a function of the concentration of the chemical in the solution.
- When only the light at this wavelength is used, Beer’s law is obeyed and maximum sensitivity is obtained for the instrument.
- Use of the narrow wavelength band usually makes possible the elimination of the absorption effects of other chemicals in the solution.
- However, the effect of some chemicals cannot be eliminated if they change the complex ion formation of the chemical being measured. This is the case when uranyl nitrate is measured in a solution containing nitric acid. .. . More Read