Determination of absorption and fluorescence excitation spectra for phytoplankton

1984 ◽  
pp. 157-169 ◽  
Author(s):  
B. G. Mitchell ◽  
D. A. Kiefer
Keyword(s):  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra

A Spectrophotometric Procedure, Using Carboxypeptidase A, for the Quantitative Measurement of Ochratoxin A

1976 ◽  
Vol 59 (1) ◽  
pp. 128-129
Author(s):  
Karl Hult ◽  
Sten Gatenbeck
Keyword(s):  
Quantitative Determination ◽  
Ochratoxin A ◽  
Quantitative Measurement ◽  
Carboxypeptidase A ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra ◽  
Ochratoxin Α ◽  
The Difference

Abstract In the method described, ochratoxin A is cleaved into ochratoxin α (free isocoumarin chromophore) and phenylalanine, using carboxypeptidase. Detection is based on the difference in fluorescence excitation spectra of ochratoxin A (380 nm, maximum) and ochratoxin α (340 nm, maximum). The quantitation of ochratoxin A is based on the loss of fluorescence intensity at 380 nm. The method has been used for the quantitative determination of as little as 4 μg ochratoxin A/kg barley and barley meal but it could be extended to other products.

The fluorescence excitation spectra of the A 1Au(S1)–X 1Ag(S0) transition of biacetyl: Determination of the band origin

1999 ◽  
Vol 111 (14) ◽  
pp. 6650-6651 ◽  
Author(s):  
Yang Chen ◽  
Linsen Pei ◽  
Jin Jin ◽  
Yide Gao ◽  
Xingxiao Ma ◽  
...  
Keyword(s):  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Band Origin ◽  
Fluorescence Excitation Spectra

Laser-Induced Fluorescence Excitation Spectra oftert-Butoxy and 2-Butoxy Radicals

1999 ◽  
Vol 103 (41) ◽  
pp. 8207-8212 ◽  
Author(s):  
Chuji Wang ◽  
Liat G. Shemesh ◽  
Wei Deng ◽  
Michael D. Lilien ◽  
Theodore S. Dibble
Keyword(s):  
Laser Induced Fluorescence ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra

scholarly journals Single-Cell and Bulk Fluorescence Excitation Signatures of Seven Phytoplankton Species During Nitrogen Depletion and Resupply

2018 ◽  
Vol 73 (3) ◽  
pp. 304-312 ◽  
Author(s):  
Stefan T. Faulkner ◽  
Cameron M. Rekully ◽  
Eric M. Lachenmyer ◽  
Ergun Kara ◽  
Tammi L. Richardson ◽  
...  
Keyword(s):  
Single Cell ◽  
Aquatic Ecosystems ◽  
Single Cells ◽  
Vital Role ◽  
Phytoplankton Species ◽  
Nitrogen Depletion ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra ◽  
Taxonomic Groups

Phytoplankton play a vital role as primary producers in aquatic ecosystems. One common approach to classifying phytoplankton is fluorescence excitation spectroscopy, which leverages the variation in types and concentrations of pigments among different phytoplankton taxonomic groups. Here, we used a fluorescence imaging photometer to measure excitation ratios (“signatures”) of single cells and bulk cultures of seven differently pigmented phytoplankton species as they progressed from nitrogen N-replete to N-depleted conditions. Our objective was to determine whether N depletion alters the fluorescence excitation signature of each species and, if so, how quickly they recover when N (as nitrate) was resupplied, because these factors affect our ability to classify the species correctly. Of the seven species studied, only Proteomonas sulcata, a marine cryptophyte, showed measurable changes in single-cell fluorescence excitation ratios and bulk fluorescence excitation spectra. These changes were likely due to decreases in the cellular concentration of phycoerythrin, a N-rich pigment, as N became scarce. Within 3 h of resupply of N, fluorescence signatures began returning to pre-depletion values and were indistinguishable from N-replete cells by 80 h after resupply. These data suggest that our classification approach is robust for non-PE containing phytoplankton. PE-containing phytoplankton might exhibit systematic changes in their signatures depending on their level of N depletion, but this could be detected and the phytoplankton re-classified following a few hours of incubation in N replete conditions.

Photoassociation due to electron transfer. Exciplex formation in non-polar solvent

1971 ◽  
Vol 24 (9) ◽  
pp. 1797 ◽  
Author(s):  
RJ McDonald ◽  
BK Selinger
Keyword(s):  
Polar Solvent ◽  
Excitation Energy Transfer ◽  
Acceptor Pair ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Exciplex Formation ◽  
Reversible Dissociation ◽  
Fluorescence Excitation Spectra ◽  
Donor Acceptor ◽  
Donor Acceptor Pair

Exciplexes may be formed by exciting either partner of a given electron donor-acceptor pair. As the formation of such exciplexes is reversible, dissociation may lead to excitation energy transfer. ��� The temperature dependence of fluorescence excitation spectra has proved to be a powerful tool for exploring these systems.

scholarly journals Plasmon enhancement of fluorescence of phthalocyanines metallocomplexes in solutions of silver nanoparticles

2019 ◽  
Vol 220 ◽  
pp. 03003
Author(s):  
Aleksandr Starukhin ◽  
Vladimir Apyari ◽  
Aleksander Gorski ◽  
Andrei Ramanenka ◽  
Aleksei Furletov
Keyword(s):  
Silver Nanoparticles ◽  
Silicon Dioxide ◽  
Binary Mixtures ◽  
Low Temperatures ◽  
Plasmonic Enhancement ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Hydrophobic Compounds ◽  
Fluorescence Excitation Spectra ◽  
Plasmon Enhancement

A method of creation of aqueous solutions with silver nanoparticles for studying of fluorescence of hydrophobic compounds has been proposed for metallocomplexes of phthalocyanines. The effect of silver nanoparticles on the fluorescence of phthalocyanines metallocomplexes at room and low temperatures was studied. The addition of silver nanoparticles leads to plasmonic enhancement of signals in fluorescence and fluorescence excitation spectra of the compounds of interest from 1,5 to more than 7 times. The lifetimes and quantum yield of fluorescence were measured for solutions of metallophthalocyanines in binary mixtures and in binary mixtures with the addition of silver triangular nanoplates with shells of silicon dioxide.

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