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.
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.
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.
A more stable colorimeter can be made if the dual beam principle is utilized. This is usually accomplished by comparing the light intensity at an absorption wavelength with the intensity of a reference beam from the same light source.
List of Uses of Colorimeter
A colorimeter uses the human eye as the detector. The user compares the observed colour of the unknown sample against a standard or a series of coloured standards of known concentrations.
- Colorimeter is a small and portable device that can be used to analyze the colour contrast and the brightness on a television or computer screen, allowing the user to adjust the settings to obtain the best quality picture.
- In the printing industry, this device is a basic element in a colour management system, in addition to checking the electronic components and quality of pulp paper and measuring the quality of the printing ink.
- The colorimeter is also used by diamond merchants to measure the optical properties of precious stones.
- The instrument is also used in cosmetology to measure the sun protection factor of the products that are applied to the skin.
- These can analyse the skin tomes and tooth colour to help diagnose the dermal and dental diseases.
- In real life the hospitals use some types of these devices to test the concentration of haemoglobin in blood. When the Hb is oxygen rich, the blood appears red.
- A high concentration of Hb within the blood is an indicator of good health, while the low levels suggest that the muscles internal organs and brain are not receiving sufficient supply of oxygen.
- The colorimeter is also used to test for water quality in real life by screening for chemicals such as chlorine, fluoride, cyanide, dissolved oxygen, iron, molybdenum and hydrazine.
Frequently Asked Questions on Uses of Colorimeter
What is the use of colorimeters in a biochemistry laboratory?
A laboratory colorimeter, also known as a digital colorimeter, is an instrument used to measure the absorption of wavelengths of light by a sample at a given frequency (colour).
How do you use a colorimeter to measure concentration?
Choose the light filter or LED that gives full absorbance. Chart the data in order to get an absorbance graph versus concentration. Then use the instrument to calculate the test solution’s absorbance, and use the graph to calculate the solute concentration in the test solution.
Why is colorimetry important?
Colorimetry, wavelength measurement and electromagnetic radiation intensity in spectrum area visible. It is commonly used to classify and assess concentrations of light-absorbing substances.x
What are the applications of colorimetry?
Colorimeters are used for a wide variety of applications in the chemical and biological fields including, but not limited to, analysis of blood, water, soil nutrients and foodstuffs, determination of solution concentration, determination of reaction levels, determination of bacterial crop growth.
How is colorimetry used in real life?
Unlike spectrophotometry, colorimetry is a method of calculating color values as perceived by the human visual system. This is used in applications that suit colors, such as matching paint colors. This is used to measure the consistency of foods by testing their signature color to ensure they are not spoiled.