Differences arising in the determination of the atmospheric extinction coefficient by transmission and target reflectance measurements

1986 ◽  
Vol 25 (3) ◽  
pp. 398 ◽  
Author(s):  
R. B. Smith ◽  
A. I. Carswell
Keyword(s):  
Extinction Coefficient ◽  
Atmospheric Extinction ◽  
Reflectance Measurements

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.

On the Measurement of Atmospheric Extinction by Rufener’s Method

1979 ◽  
Vol 3 (5) ◽  
pp. 326-327
Author(s):  
Z. KviZ
Keyword(s):  
Adverse Effect ◽  
Photometric System ◽  
Photoelectric Photometry ◽  
Atmospheric Extinction ◽  
Air Mass

The coefficient of atmospheric extinction may change during the night and in fact it often does. This has an adverse effect on the determination of atmospheric extinction by simple Bouguer plot of magnitude against air mass. This effect was studied by Rufener (1964), who introduced for the purpose of accurate photoelectric photometry in the Geneva photometric system the method of two ‘extinction stars’. His method consists of the measurement of two stars of the same colour — one starting at high air mass 2 - 3, the M-star (for French montante = rising) and the second starting simultaneously in the meridian at low air mass, the D—star (for descending).

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