Extinction coefficient formula

The separations allowed by the partition column provided a rather pure sample of pyrethrin I, demonstrated by the gas chromatograph and by comparison with known infrared spectra. The purified pyrethrin I was weighed quantitatively and a color test performed to determine the extinction coefficient. The figure obtained from ten runs is 1120, calculated from the formula ... 

Due to varying solvent systems, varying purities and water contents of purified pigments, different molar extinction coefficients have been reported." - - The most reliable ones commonly applied are 60,000 L/mol cm for betanin, 56,600 L/mol cm for amaranthin, and 48,000 L/mol cm for betaxanthins. ° Pigment contents may be calculated with the following formulae." - ... 

The level of substitution of the antibody after reaction with SPDP is determined spectrophotometrically. A sample of the derivatized antibody is treated with DTT at a final concentration of 5 mM, and the optical density measured at 280 nm and 343 nm. The pyndine-2-thione released by reduction has a molar extinction coefficient at 343 nm of 8.08 x 103Mcm (12) This product also absorbs at 280 nm with a molar extinction coefficient of 5.1 x 103M/cm. The true protein absorbance is determined from the formula ... 

It has been noted by Potasek [105] that electron tunneling in the donor-acceptor pair D-A may lead to the appearance of a charge transfer band in the absorption spectrum of this pair. The author obtained the following formula describing the dependence of the extinction coefficient, , of this band on the energy, E, of the absorbed light quantum... 

The molar extinction coefficient a is calculated with the following formula ... 

Note Abbreviations used in subsequent tables are shown (Abb.) along with chemical formulae, molecular weights (mw), wavelengths of maximum absorbance (k, in nm), extinction coefficients (e) at k or other indicated wavelengths, and species from which original identifications were made. (Compounds are listed in order of molecular weight.)... 

For each of the diluted Standard Solutions—1, 2, and 3— plot absorbance against p-nitroaniline mM concentration. The result is a straight line that passes through the origin. Calculate the millimolar extinction coefficient (e) of each Standard p-Nitroaniline Solution using the following formula ... 

In order to calculate the light intensity which is present in the volume Vj, the light penetration at the depth of water where V, is located must be evaluated. The rate at which light is attenuated with respect to depth is given by the extinction coefficient, ke. That is, at a depth z, the intensity at that depth, I(z), is related to the surface intensity, I0, by the formula... 

The basic theory for the study of the scattering of light by aerosols was presented by Mie (1908). This theory generally assumes an ensemble of identical spherical particles and requires considerable computing resources for its solution. Modifications to allow for cylindrical and ellipsoidal particles have also been developed. In practice, simplified formulas are often used (see, e.g., Van de Hulst, 1957). The total extinction coefficient at a particular wavelength can be determined by integration over all particle radii r... 

The concentration of primers and probes is determined by measuring the absorbance at 260 nm of an appropriate dilution in TE buffer. The oligonucleotide concentration (C) in M is calculated by computing the extinction coefficient factors (see Note 7), using the following formula ... 

In their original work Hammett measured the ionization ratio by determining the color change of the indicator in a colorimeter. Since then such measurements are carried out spectrophotometrically using the formula in equation 30 for calculating the ionization ratio ( bh+, b, and a, are the extinction coefficients of the acid form of the indicator, its basic form, and the solution, respectively). 

As shown in following formula, Lambert-Beers law allows the absorption values to be converted to quantitative results if the molar extinction coefficient is known (see also Tables 5 and 6). 

The infrared quality factor or material Q can be obtained with a measurement of the extinction coefficient a. A detailed discussion of the theory behind this measurement is provided in an article by Brice (1985). An approximation to the extinction coefficient called is obtained for several wave numbers of interest (wave number is reciprocal of wavelength). The value of Q is then calculated from the formula... 

Dilute 10 jxL of the KLH-SPDP fraction with 90 xL of the phosphate buffer and measure the absorbance at 343 nm before and after the addition of 2 xL of dithiothreitrol Calculate the coupling efficiency from the following formula using the moIar-extinction coefficient for the release pyridine-2-tion, 8.08 X 1Q3 M- ... 

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