Fluorescence Quenching of Polycyclic Aromatic Hydrocarbons by Cetylpyridinium Bromide: Discrimination between Alternant and Nonalternant Hydrocarbons

1997 ◽  
Vol 51 (3) ◽  
pp. 380-386 ◽  
Author(s):  
Juan H. Ayala ◽  
Ana M. Afonso ◽  
Venerando González
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Fluorescence Quenching ◽  
Aromatic Hydrocarbons ◽  
Dynamic Quenching ◽  
Quenching Mechanism ◽  
Cetylpyridinium Bromide ◽  
Polycyclic Hydrocarbons ◽  
Polycyclic Aromatic ◽  
Premicellar Aggregates ◽  
Fluorescence Dynamic

Molecules of polycyclic hydrocarbons (PAHs) that contain between two and five rings undergo quenching processes in the presence of cetylpyridinium bromide (CPB), which can act as quencher and as surfactant. The CPB concentration and the nature of the PAHs notably influence the inhibition mechanisms of fluorescence. Dynamic quenching is predominant for all hydrocarbons in solutions in which CPB is found in the form of monomers. When the quencher forms premicellar aggregates, fluoranthene, benzo[ a]pyrene, and benz[ a]anthracene undergo dynamic quenching, while for the remaining PAHs the dynamic and static processes coexist. In micellar CPB solutions the static quenching mechanism is predominant. The correlations existing between the quenching constant in the premicellar zone and topological and geometrical descriptors of the PAHs show the different behavior of alternant and nonalternant hydrocarbons.

On the Fluorescence Quenching of Polycyclic Aromatic Hydrocarbons by Nitromethane

1975 ◽  
Vol 30 (10) ◽  
pp. 1311-1314 ◽  
Author(s):  
H. Dreeskamp ◽  
E. Koch ◽  
M. Zander
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Fluorescence Quenching ◽  
Rate Constant ◽  
Aromatic Hydrocarbons ◽  
High Energy ◽  
Dynamic Quenching ◽  
Quenching Mechanism ◽  
Polycyclic Aromatic ◽  
Acetonitrile Solutions ◽  
Alternant Hydrocarbons

Abstract Fluorescence quenching of 22 polycyclic aromatic hydrocarbons by nitromethane in toluene and acetonitrile solutions has been studied. Contrary to Sawicki’s observations that the fluorescence of hydrocarbons with the fluoranthene skeleton is not quenched that of 11.12-and 3.4-benzofluor-anthene and fluoranthene itself is quenched. These compounds have a high energy of the fluorescence transition. The fluorescence quenching of the compounds investigated follows a dynamic quenching mechanism. The bimolecular rate constant of fluorescence quenching increases exponentially with the energy of the fluorescing state of alternant hydrocarbons.

Sorption of Polycyclic Aromatic Hydrocarbons onto Natural Solids: Determination by Fluorescence Quenching Method

1991 ◽  
Vol 23 (1-3) ◽  
pp. 427-436 ◽  
Author(s):  
Y. Shimizu ◽  
H. M. Liljestrand
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Organic Carbon ◽  
Fluorescence Quenching ◽  
Aromatic Hydrocarbons ◽  
Organic Carbon Content ◽  
Polycyclic Aromatic ◽  
Fluorescence Quenching Method ◽  
Quenching Method ◽  
Solid Liquid ◽  
Solid Liquid Separation

A fluorescence quenching method was used to determine the sorption of polycyclic aromatic hydrocarbons (PAHs) onto natural solids in batch experiments. This method is based upon the observation that PAHs fluoresce in aqueous solution but not when associated with natural solids. It avoids problems of incomplete solid-liquid separation. As natural solids, eleven different USEPA soils and sediments were used. Anthracene and 2-aminoanthracene, which are respectively non-ionic and ionic PAHs, were chosen as sorbates. The fractional decrease in fluorescence intensity as a function of added natural solid concentration is referred to as Stem-Volmer plots. The plots were linear for all natural solids investigated. The conditional sorption coefficients (Ksc) at pH 6 through 8 and I=0.1 M were obtained as the slopes of the plots. While the Ksc values of anthracene were independent of pH, the values of 2-aminoanthracene decreased with increasing pH. The Ksc values of anthracene correlated well with the organic carbon content of natural solids. However, the values of 2-aminoanthracene did not depend on the content of organic carbon in natural solids. For 2-aminoanthracene, inorganic matrices of the natural solids may contribute to the sorption.

Photophysical and Photochemical Studies of Polycyclic Aromatic Hydrocarbons in Solutions Containing Tetrachloromethane II. The Solvent Effect on the Fluorescence Quenching of Aromatic Hydrocarbons by Tetrachloromethane

1987 ◽  
Vol 42 (11) ◽  
pp. 1290-1295 ◽  
Author(s):  
Wiesław M. Wiczk ◽  
Tadeusz Latowski
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Fluorescence Quenching ◽  
Solvent Effect ◽  
Aromatic Hydrocarbons ◽  
Large Concentration ◽  
Specific Interactions ◽  
Two Component ◽  
Polycyclic Aromatic

Fluorescence quenching of aromatic hydrocarbons in a large concentration range of the quencher has been studied in a variety of two-component mixtures of tetrachloromethane with other solvents. In aliphatic solvents the process could be described by the Stern-Volmer equation, whereas in the remaining mixtures the fluorescence quenching curves showed a parabolic behaviour which has been explained in terms of specific interactions between the components of the mixtures.

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