A NOTE ON THE DETERMINATION OF THE EXTINCTION COEFFICIENT OF AEROSOLS

1947 ◽  
Vol 25a (1) ◽  
pp. 62-67
Author(s):  
G. O. Langstroth ◽  
J. L. Wolfson
Keyword(s):  
Light Beam ◽  
Extinction Coefficient ◽  
Photoelectric Cell ◽  
Smoke Chamber

Difficulties were encountered in smoke chamber experiments in obtaining reliable extinction coefficient data by methods based on brightness measurements of bright and 'black' surfaces seen through the smoke. These difficulties led to an investigation of the reliability of a commonly used method employing a parallel light beam and a photoelectric cell. The results indicate that the method is capable of yielding extinction coefficient data with an accuracy of 1 to 2% under the conditions of our experiments.

scholarly journals A spectrophotometric method for determination of fluorophore-to-protein ratios in conjugates of the blue fluorophore 7-amino-4-methylcoumarin-3-acetic acid (AMCA)

1990 ◽  
Vol 38 (1) ◽  
pp. 87-94 ◽  
Author(s):  
M W Wessendorf ◽  
S J Tallaksen-Greene ◽  
R M Wohlhueter
Keyword(s):  
Acetic Acid ◽  
Optical Density ◽  
Extinction Coefficient ◽  
Spectrophotometric Method ◽  
Extinction Coefficients ◽  
Beer's Law ◽  
Beer’S Law ◽  
The Given

7-Amino-4-methylcoumarin-3-acetic acid (AMCA) has been found to be a useful fluorophore for immunofluorescence. The present study describes a spectrophotometric method for determining the ratio of moles AMCA to moles protein (or the f/p ratio) in an AMCA-conjugated IgG. The concentration of a substance absorbing light can be determined spectrophotometrically using Beer's Law: Absorbance = Concentration x Extinction coefficient. From Beer's law, one can derive the following formula for determining the f/p ratio of AMCA-IgG conjugates: f/p = (epsilon 280IgG).A350 - (epsilon 350IgG).A280/(epsilon 350AMCA).A280 - (epsilon 280AMCA).A350 where A is the optical density of the conjugate at the given wavelength and epsilon is the extinction coefficient of a substance at the wavelength specified. Using conjugates of model proteins, it was found that the extinction coefficients of the AMCA moiety of AMCA-conjugated protein were 1.90 x 10(4) at 350 nm and 8.29 x 10(3) at 280 nm. Similarly, it was found that the extinction coefficients of swine IgG were 1.56 x 10(3) at 350 nm and 1.26 x 10(5) at 280 nm. Thus, for AMCA-conjugated swine IgG: f/p = (1.26 x 10(5)).A350 - (1.56 x 10(3)).A280/(1.47 x 10(4)).A280 - (6.42 x 10(3)).A350 [corrected]. Based on this formula, the f/p ratios of some AMCA-IgG conjugates useful for immunohistochemistry have been found to range between 6 and 24.

scholarly journals Experimental Determination of the Absorption Cross-Section and Molar Extinction Coefficient of Colloidal CdSe Nanoplatelets

2015 ◽  
Vol 119 (47) ◽  
pp. 26768-26775 ◽  
Author(s):  
Aydan Yeltik ◽  
Savas Delikanli ◽  
Murat Olutas ◽  
Yusuf Kelestemur ◽  
Burak Guzelturk ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Cross Section ◽  
Extinction Coefficient ◽  
Absorption Cross Section ◽  
Molar Extinction Coefficient ◽  
Absorption Cross

Determination of all Dimensions of CdSe Seeded CdS Nanorods Solely via their UV/Vis Spectra

2017 ◽  
Vol 231 (1) ◽  
Author(s):  
Patrick Adel ◽  
Julian Bloh ◽  
Dominik Hinrichs ◽  
Torben Kodanek ◽  
Dirk Dorfs
Keyword(s):  
Absorption Spectra ◽  
Extinction Coefficient ◽  
Core Diameter ◽  
The Core ◽  
Extinction Spectra ◽  
Cds Nanorods ◽  
Fast Route ◽  
Characteristic Points ◽  
Electron Microscopical

AbstractIn the present manuscript we develop a method to determine all characteristic dimensions of CdSe seeded CdS nanorods solely via their extinction spectra without the need for electron microscopical investigations. In detail, the core diameter as well as the overall diameter and length and the molar extinction coefficient can all be derived from characteristic points in the absorption spectra. We carefully investigate in which size regime our assumptions are valid and give an estimation of the expected error, making it possible for the reader to decide whether this method is sufficiently accurate for their respective system. Our method displays a comfortable and fast route to analyze these nowadays often used nanorods.

scholarly journals Measurement of Visibility and Present Weather Detection Using Scattering Technique of Light

2020 ◽  
pp. 07-10
Keyword(s):  
Light Beam ◽  
Extinction Coefficient ◽  
Narrow Band ◽  
Scattered Signal ◽  
Forward Scatter ◽  
Scattering Technique

A forward-scatter meter measures a small portion of light scattered out of a light beam into a relatively narrow band of scattering angles. The forward-scatter meter measurement is then used to estimate the extinction coefficient; the scattered signal is assumed to be proportional to the extinction coefficient.

Disubstituted hydroxamic acids and the determination of vanadium

1968 ◽  
Vol 46 (2) ◽  
pp. 327-330 ◽  
Author(s):  
R. M. Cassidy ◽  
D. E. Ryan
Keyword(s):  
Extinction Coefficient ◽  
Metal Chelate ◽  
Visible Region ◽  
Hydroxamic Acids ◽  
Molecular Extinction Coefficient ◽  
Sensitivity Increase ◽  
Chelate Rings

A number of disubstituted hydroxamic acids were investigated as possible replacements for benzoylphenylhydroxylamine in the determination of vanadium; none is superior. At 378 mμ., p-phenylazobenzoylphenylhydroxylamine shows a marked sensitivity increase but selectivity is poor. In the visible region, there is an increase in molecular extinction coefficient as the reagent π system is extended; how ever, complete coplanarity of the aromatic and metal chelate rings is not possible and the increase is not large enough to be of much practical value.

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