Colorimeters
The color and the amount of light absorbed or transmitted by a liquid can be used to determine the concentration of a substance in that liquid.
What Is a Colorimeter?
A colorimeter measures the amount of light that passes through the solution as compared to the light that would pass through a pure solvent.
A photocell detects the amount of light passing through the solution and converts the light to an electrical signal. Higher concentrations and colors increase light absorption and the current produced by the photocell.
What Types of Colorimeters Are There?
Colorimeters may be visual or photoelectric. Visual colorimeters may be visual absorption meters or color comparators or true visual or tristimulus colorimeters.
Visual colorimeters compare the color of the test sample with a standard. These instruments are used for chemical analysis, determining concentration, or grading based on color. A tristimulus colorimeter works on the principle of visual equivalence and is more commonly used to monitor production of colored objects.
Photoelectric colorimeters can measure colors directly using filters and photoelectric cells. Light reflected or transmitted from the object passes through various filters to reach the photon detectors.
How Are Colorimeters Used?
Many scientific colorimeters are designed to measure single or multiple parameters like chlorine that are frequently tested in drinking water, wastewater, food and beverages, aquaculture, and agriculture.
Colorimeters are also used to objectively measure the color of beers, malts, and caramels and industrial, mineral, and edible oils, fats, waxes, petrochemicals, and surfactants.