absorbance

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absorbance

 [ab-sor´bans]
in radiology, a measure of the ability of a medium to absorb radiation, expressed as the logarithm of the quotient of the intensity of the radiation entering the medium divided by that leaving it.

ab·sor·bance (A, A),

(ab-sōr'bants),
spectrophotometry log of the ratio of the radiant power of the incident radiation to the radiant power of the transmitted radiation.

absorbance

/ab·sor·bance/ (-sor´bans)
1. in analytical chemistry, a measure of the light that a solution does not transmit compared to a pure solution. Symbol .
2. in radiology, a measure of the ability of a medium to absorb radiation, expressed as the logarithm of the ratio of the intensity of the radiation entering the medium to that leaving it.

absorbance

[əbsôr′bəns]
the degree of absorption of light or other radiant energy by a medium exposed to the energy. It is expressed as the logarithm of the ratio of energy transmitted through a vacuum to the energy transmitted through the medium. For solutions, it is the logarithm of the ratio of energy transmitted through pure solvent to the energy transmitted through the solution. Absorbance varies with factors such as wavelength, solution concentration, and path length.

Absorbance

Chemistry A logarithm of the percent transmission of a wavelength of light through a liquid. 
Microbiology A measure of the amount of light absorbed by a suspension of bacteria or an organic solution, measured by spectrophotometry. Absorbance values are used to plot the growth of bacteria in broth and gauge the purity and concentration of molecules in solution.

ab·sor·bance

(ăb-sōr'băns)
spectrophotometry 2 minus the log of the percentage transmittance of light.
Synonym(s): extinction (2) , optic density.

absorbance

a spectrophotometric measurement of the light absorbed by a solution at a particular WAVELENGTH. The absorbance (A) derives from the percentage of light transmitted as follows:

where Io is the incident light intensity and I is the transmitted light intensity. The absorbance is related to the molar absorption coefficient (extinction coefficient) e (cm-1M-1), concentration c (M), and path length l (cm) as follows:

Absorbance can therefore be used to determine the concentration of a substance in solution, to follow conversion of a SUBSTRATE to a product in an enzymic reaction (see ENZYME), and so on.

Absorbance is sometimes referred to as OPTICAL DENSITY, although this term should be used for measurement of light scattering.

absorbance 

A measure of absorption equal to the logarithm to the base 10 of the reciprocal of the transmittance T, for a specified wavelength and expressed as A = −log10 T. Syn. optical density. See optical density; transmittance.

absorbance

in radiology, a measure of the ability of a medium to absorb radiation, expressed as the logarithm of the quotient of the intensity of the radiation entering the medium divided by that leaving it.
References in periodicals archive ?
Interestingly, the PCR-ONH assay also yielded a subtly abnormal result in this patient: the observed absorbance ratio was 0.
The situation changes, however, in the transmission window region, where sensitivity to location and pressure are increased at the same time that the analyte absorbances are much smaller.
This allows for analysis of 30 plasma MTX samples in duplicate, including calibrators and controls, with one 20-min reading in a microplate reader that measures the absorbance of ultraviolet light.
The magnet-supporting frame was juxtaposed with or removed from the microtiter plate and remained associated with the plate while the absorbance was measured in the microtiter plate reader.
3)) depends on two factors, the first factor contains terms which depend on the measured absorbances inside (subscript 1) and outside (subscript 3) the IS detector, and the second factor contains a ratio of the detection efficiency at the excitation, [lambda], and emission, [[lambda].
High absorbance values for samples and/or positive control - absorbance does not go down as the sample is diluted down the plate), might be caused by:
Where, Ac is absorbance of control, As is the absorbance of sample.
The basic structure of equipment is composed of a photometric clamp, figure 1, which has two semicircular electrodes of stainless steel sheet on each clamping die molded on glass tube, each electrode presenting a hole through which the radiation of a LED, passes on a clamping die of the clip, to a photodiode receiver, located on the other clamping die, monochromatic radiation emitted by the LED having a wavelength corresponding to maximum optical absorbance of the analyzed chemical species, the combined photometer also includes an electrical cable for connection and an electronic part.
We also wanted to determine whether the absorbance of individual layers could be added to obtain the total system absorbance as logically inferred from Beer's law.
A (970), A (723) and A (2236) are the absorbances of the corresponding bonds.
450]) method, the absorbance at 450 run is used as a surrogate for concentration of amniotic bilirubin.