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Most commonly, antioxidant capacity is measured using the ABTS Decolorization Assay. Other antioxidant capacity assays which use Trolox as a standard include the diphenylpicrylhydrazyl ( DPPH ), oxygen radical absorbance capacity ( ORAC ) and ferric reducing ability of plasma ( FRAP ) assays.
DPPH has two major applications, both in laboratory research: one is a monitor of chemical reactions involving radicals, most notably it is a common antioxidant assay, [1] and another is a standard of the position and intensity of electron paramagnetic resonance signals.
Trolox equivalency is most often measured using the ABTS decolorization assay. [1] The TEAC assay is used to measure antioxidant capacity of foods, beverages and supplements. Ferric reducing ability of plasma (FRAP) is an antioxidant capacity assays which uses Trolox as a standard.
Ferric reducing ability of plasma (FRAP, also Ferric ion reducing antioxidant power) is an antioxidant capacity assay that uses Trolox as a standard. [1] The FRAP assay was first performed by Iris Benzie and J. J. Strain of the Human Nutrition Research Group at the University of Ulster, Coleraine.
K i is the inhibition constant for a drug; the concentration of competing ligand in a competition assay which would occupy 50% of the receptors if no ligand were present. [ 5 ] The Cheng-Prusoff equation produces good estimates at high agonist concentrations, but over- or under-estimates K i at low agonist concentrations.
The most commonly used test is called a TBARS Assay (thiobarbituric acid reactive substances assay). Thiobarbituric acid reacts with malondialdehyde to yield a fluorescent product. However, there are other sources of malondialdehyde, so this test is not completely specific for lipid peroxidation. [14]
Conversely, in an indirect dilution assay the dose levels are administered at fixed dose levels, so that the response is a stochastic variable. In some assays, there may be strong reasons for believing that all the constituents of the test preparation except one, are without any effect on the studied response of the subjects.
There are different definitions within laboratory quality control, wherein "analytical sensitivity" is defined as the smallest amount of substance in a sample that can accurately be measured by an assay (synonymously to detection limit), and "analytical specificity" is defined as the ability of an assay to measure one particular organism or ...