Phenol coefficient
Encyclopedia
Phenol coefficient is a measure of the bactericidal activity of a chemical compound in relation to phenol
. When listed numerically, the figure expressing the disinfecting
power of a substance by relating it to the disinfecting power of phenol may be a function of the standardized test
performed. For example, the Rideal-Walker method gives a Rideal-Walker coefficient
and the U.S. Department of Agriculture method gives a U.S. Department of Agriculture coefficient.
To calculate phenol coefficient, the concentration of the test compound at which the compound kills the test organism in 10 minutes, but not in 5 minutes, is divided by the concentration of phenol that kills the organism under the same conditions. The phenol coefficient may be determined in the presence of a standard amount of added organic matter
or in the absence of organic matter. and the formula is given by N=1/CT where C is the conc. of agent applied and T is the time for which agent is applied and N is the number of survivors so N is inversely proportional to dose (CT is collectively called dose)
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
. When listed numerically, the figure expressing the disinfecting
Disinfection
Disinfectants are substances that are applied to non-living objects to destroy microorganisms that are living on the objects. Disinfection does not necessarily kill all microorganisms, especially nonresistant bacterial spores; it is less effective than sterilisation, which is an extreme physical...
power of a substance by relating it to the disinfecting power of phenol may be a function of the standardized test
Standardized test
A standardized test is a test that is administered and scored in a consistent, or "standard", manner. Standardized tests are designed in such a way that the questions, conditions for administering, scoring procedures, and interpretations are consistent and are administered and scored in a...
performed. For example, the Rideal-Walker method gives a Rideal-Walker coefficient
Rideal-Walker coefficient
The Rideal-Walker coefficient is a figure expressing the disinfecting power of any substance and is obtained by dividing the figure indicating the degree of dilution of the disinfectant that kills a microorganism in a given time by that indicating the degree of dilution of phenol that kills the...
and the U.S. Department of Agriculture method gives a U.S. Department of Agriculture coefficient.
To calculate phenol coefficient, the concentration of the test compound at which the compound kills the test organism in 10 minutes, but not in 5 minutes, is divided by the concentration of phenol that kills the organism under the same conditions. The phenol coefficient may be determined in the presence of a standard amount of added organic matter
Organic matter
Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...
or in the absence of organic matter. and the formula is given by N=1/CT where C is the conc. of agent applied and T is the time for which agent is applied and N is the number of survivors so N is inversely proportional to dose (CT is collectively called dose)