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.
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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
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 it is 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.
There are two types of colorimeters that are used to measure colour. These are tristimulus colorimeters and spectrophotometers.
The main purpose of this is aiding 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.
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.
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), to 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.
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.
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.
1. State the Principles of the Colorimeter.
Colorimeter refers to a photometric technique that explains that when a beam of light passes through a solution then a part of the light is reflected and a part is absorbed while the rest of the remaining light transmits.
It is based on two laws that are:
i) Lambert’s Law
According to Lambert’s law, the total amount of light that is absorbed is directly proportional to its length and thickness of a solution.
ii) Beer’s Law
According to this, the total amount of light that is absorbed is directly proportional to the concentration of solute.
2. State How a Colorimeter Works.
Step 1: Before you start the experiment make sure you calibrate the colorimeter. This can be done by using the standard solution
Step 2: A ray of light passes through the direction of the solution. The light then passes a series of various filters and lenses.
Step 3: As soon as the beam of light finally reaches the cuvette, then it transmits, reflects as well as absorbs.
Step 4 : The electrical signal is measured by using a galvanometer.