Detail publikace

Some remarks on the origin of lignite humic acids optical properties

ČECHLOVSKÁ, H. VÁLKOVÁ, D. GRASSET, L. FASUROVÁ, N. KUČERÍK, J.

Originální název

Typ

článek v časopise - ostatní, Jost

Jazyk

angličtina

Originální abstrakt

Humic acids (HA) isolated from lignite of South Moravian and North Czech region (leonardite) were characterized by elemental analysis and fluorescence spectroscopy analysis. From both humic acids there were sequentially extracted water soluble fractions, free and bond fatty acids which were consequently characterized by CPMAS 13C-NMR spectroscopy and GC-MS analysis. The respective rests were dissolved in sodium hydroxide and the synchronous fluorescence spectroscopy (SFS) was used to analyze the character of present fluorophores and assess the influence of extracted molecules on the fluorescence of humic acids. The results has revealed a number of essential outcomes for the elaboration of fluorescence records of humic matter: i) based on our and other measurements, the optical properties of humic acids could not be aresult of the superposition of numerous independent chromophores, but rather of their mutual interactions; it seems, that SFS evaluates predominantly hydrophobic core of humic aggregates which has apparently highly aromatic character, ii) the inner core of a humic aggregate do not necessarily consists of condensed structures, the high aromaticity degree can be a consequence of weak interactions of simple aromatic moieties such as pi-pi stacking and CH-pi; iii) the crucial factor in SFS measurement is quenching which can be caused both by molecules present outside and inside of a humic aggregate; iv) due to the unique and complicated secondary structure of humic acids the molecules which are not primarily fluorophores can significantly affect the fluorescence due to their interaction with fluorophores.

Klíčová slova

synchronous fluorescence spectroscopy, lignite humic acids, extractions, supramolecular structure

Autoři

ČECHLOVSKÁ, H.; VÁLKOVÁ, D.; GRASSET, L.; FASUROVÁ, N.; KUČERÍK, J.

Rok RIV

2009

Vydáno

14. 2. 2009

Nakladatel

Slovnaft Bratislava

Místo

Slovensko

ISSN

1335-3055

Periodikum

Petroleum and Coal

Ročník

Číslo

Stát

Slovenská republika

Strany od

Strany do

Strany počet

BibTex

@article{BUT46761,
  author="Hana {Čechlovská} and Dana {Švejdová} and Laurent {Grasset} and Naděžda {Fasurová} and Jiří {Kučerík}",
  title="Some remarks on the origin of lignite humic acids optical properties",
  journal="Petroleum and Coal",
  year="2009",
  volume="51",
  number="1",
  pages="33--44",
  issn="1335-3055"
}