Tyndall’s hypochromism in suspensions

Abstract

Passage of light through a suspension is accompanied by a competition of processes of absorption and scattering for each individual particle. As a result, a hypochromism phenomenon (a decrease in the extinction coefficient) takes place. The hypochromism value increases with the growth of a particle sizes or its refractive index. Since Tyndall's light scattering in a suspension where the size of every particle is consid erably larger than the wavelength weakly depends on the wavelength, the absorption (or excitation) spectrum is almost uniformly attenuated. A simple method for determination of the true extinction coefficients of the absorption and excitation spectra of diluted suspensions which have no multiple light scattering is proposed. Experimental data on the spectra of hemoglobin in erythrocytes, actinomycin in DNA, and flavines in mito chondria are discussed.

Rapid and Efficient Collection of Platinum from Karstedt’s Catalyst Solution via Ligands-Exchange-Induced Assembly

“…It is well known that the Tyndall effect, similar to Rayleigh scattering, essentially originates from lighter scattering by colloidal particles in the medium, in that the intensity of the scattered light is positively proportional to the size and the average number of particles in the medium. 25,26 In our experiment, a very weak Tyndall effect could be barely observed when a laser beam (650 nm, 5 mW) is passed through the reaction mixture (Figure 2a), suggesting the existence of particles with very small size or little population in the Karstedt's catalyst solution (Figure 2a). The Tyndall effect gradually becomes more pronounced after the addition of propynol and stirring for 1 h as indicated by the fact that a light pathway visually becomes clear and strongly visible through the reaction mixture (Video 1 in the Supporting Information).…”

An Edible Biopolymeric Microcapsular Wrapping Integrating Lytic Bacteriophage Particles for Salmonella enterica: Potential for Integration into Poultry Feed

“…Hence, quenching of radiation owing to protein chromophore absorption and scattering by whole virion particles corrected by the quenching of radiation owing solely to protein chromophores, leads to the hallmark absorbance for a particular virion at a particular concentration [ 47 ]. Structural protein chromophores of phage virions have a nearly zero absorption of radiation (completely due to scattering [ 48 ]) at 320 nm, which one uses to correct for radiation scattering from virions and other contaminating particulates. Therefore, the structural proteins of the two phages isolated in the research work described herein contributed substantially to their absorption spectrum and were responsible for the wide plateau between 250 and 280 nm in the spectra, with a shallow maximum at 251 nm (phage ph001L) or 252 nm (phage ph001T).…”