What is Colorimeter?
Colorimeter definition refers to a device that is used to measure the waves of lights. This kind of measurement helps to find the level of concentration of a particular substance. This is due to the fact that each solution or substance absorbs or transmits a certain amount of light based on its properties and the concentration of particles present in it. It is also used to compare the total amount of light that can enter with the help of a solution and the amount of light that gets through the sample of a pure solvent.
Construction: Parts of a Colorimeter
As visible from the given diagram, a colorimeter has the following parts-
A light source
A coloured filter set
An aperture (adjustable)
A cuvette for holding the working solution
A photoresistor or detector
A display board or meter for showing reading from the detector
Colorimeter Uses and Functions
The colorimeter has a detector in it that acts just like the human eye. The user who handles the device compares the colour of the unknown substance with a prior identified series or standards. The application of colorimeters is not one but many. Here are a few colorimeter uses of significance:
A colorimeter is a very tiny and portable device that is used in analyzing the colour contrast as well as the brightness on a computer or television screen. Thus it allows the possibility of adjusting the settings and giving the best quality picture to the viewers.
It is also used in printing industries where it adds to the basic elements of colour management. It does so by adding the electronic component to manage the pulp paper and also maintains its quality along with the quality of printing ink.
It is also used by the merchants who deal in a diamond as they use it to measure the properties of the diamonds and identify whether they are real or not. A colorimeter can analyse the skin tone of a person and the tooth colour and thus helps to diagnose dental and dermal diseases that one may be experiencing.
Hospitals use colorimeters in various apparatuses to examine the concentration or level of haemoglobin in a blood sample. The blood appears to be red when the Hb is rich in oxygen. If the concentration of Hb is high then it indicates that the person is well and fit. Although, a low concentration level indicates that the person is facing some serious problems or having internal organ damage or the brain is not receiving a proper supply of blood.
It is also used in testing the quality of the water by screening chemicals like fluoride, chlorine, cyanide, hydrazine, molybdenum, iron, and dissolved oxygen.
Types of Colorimeters
There are two types of colorimeters that are used to measure colour. These are tristimulus colorimeters and spectrophotometers.
Tristimulus Colorimeter
The main purpose of this is to aid digital imaging while calibrating output devices. This particular type of colorimeter reads the measures on wideband spectral energy (a certain number of them) as found in the visible spectrum. It utilises filtered photodetectors such as silicon photodiodes. It uses three such photodetectors. Each of these has an optical filter attached to it.
Spectrophotometer
This refers to a device that has the capability of measuring the intensity of light by its colour and wavelength. It detects a whole range of UV (200-400 nm) and its visible range as well (400-800 nm). It gives accurate data after examining the wavelength through spectral analysis. This type of colorimeter is rapid and easy to use and is broadly used for measuring the light absorbed.
What is the Colorimetric Method Definition?
The colorimeter determines the wavelength and intensity of the electromagnets in its visible range of the spectrum. It is generally a tool that helps to measure the colour (used to capture), communicate it, and evaluate it. It does so for determining the concentrations of the various substances that absorb different amounts of light. It is capable of working quantitatively as well as qualitatively for analyzing colours.
Did You Know?
The most important part of the colorimeter is the aperture and the filament lamp.
The colorimeter was invented by Jules Duboscq in the year 1870.
Application Of Colorimetry
There are several applications of colorimetry and they are mentioned below.
It is used by hospitals as well as laboratories for analysing biochemical samples such as urine, cerebrospinal fluids, plasma, biochemical samples, and serum.
It is widely used to generate a quantitative estimation of the serum components, proteins, glucose, and various biochemical compounds.
It is also used in food industries and by manufacturing industries to make textiles and paints.
A colorimeter has immense significance in the ever-expanding world of science. Further research is going to enhance its features and functionalities.
Importance of Colorimeter in Chemistry
Colorimeters are traditionally utilized for the purpose of measuring the waves of light. They are used to detect colour and then find out a solution’s concentration. When the colour is being measured, the change in the intensity of electromagnetic radiation in the visible wavelength region after transmitting or reflecting by an object or solution is measured.
FAQs on Uses of Colorimeter
1. What is a colorimeter and what is its main purpose?
A colorimeter is a scientific instrument used to measure the absorbance of specific wavelengths of light by a solution. Its primary purpose is to determine the concentration of a known solute within that solution, as the amount of light absorbed is directly related to the concentration.
2. What is the basic principle a colorimeter works on?
The operation of a colorimeter is based on the Beer-Lambert law. This principle states that the amount of light absorbed by a coloured solution is directly proportional to both the concentration of the solute and the length of the path the light travels through the solution.
3. How does a colorimeter work to measure a solution's concentration?
A colorimeter measures concentration through a simple process:
- A beam of light of a specific colour is passed through the sample solution held in a transparent container called a cuvette.
- The solute in the solution absorbs a portion of this light.
- A detector on the other side measures the intensity of the light that passes through.
- By comparing the initial light intensity with the final light intensity, the device calculates the solution's absorbance, which is then used to determine its concentration.
4. Where are colorimeters commonly used in real life?
Colorimeters have many practical applications across various fields. They are commonly used in:
- Clinical Laboratories: To analyse biological samples like blood and urine for diagnostic purposes.
- Water Quality Testing: To measure levels of chemicals like chlorine or nitrates in water supplies.
- Food and Beverage Industry: To monitor and maintain colour consistency in products.
- Manufacturing: In industries such as paints and textiles to ensure accurate colour matching.
5. Why is it important to calibrate a colorimeter before taking measurements?
Calibration is a crucial step for ensuring accuracy. It involves using a 'blank' sample (the pure solvent without the solute) to set the instrument's reading to zero absorbance. This step ensures that the final measurement only reflects the light absorbed by the substance of interest and not by the solvent or the cuvette itself, preventing inaccurate results.
6. How is a colorimeter different from a spectrophotometer?
The key difference is their precision and the way they select light. A colorimeter uses simple filters to isolate broad ranges of colour (like red, green, or blue). In contrast, a spectrophotometer uses a more advanced component, like a prism, to select very specific, narrow wavelengths of light. This makes spectrophotometers more versatile and accurate for detailed scientific analysis.
7. Can a colorimeter be used to measure a colourless solution? Why or why not?
No, a standard colorimeter cannot directly measure a colourless solution. This is because the technique relies on the substance's ability to absorb light in the visible spectrum, which colourless compounds do not do. However, a colourless substance can sometimes be measured indirectly by first reacting it with a chemical that produces a coloured product.
