Study of humic acids by synchronous fluorescence spectroscopy

článek v časopise - ostatní, Jost

angličtina

Humic acids (HA) were isolated from South Moravia lignite by standard alkaline extraction (IHSS procedure). Were have also prepared samples of humates (NaHA) from lignitic humic acids. Samples of humates were dried or freeze dried. Synchronous fluorescence spectroscopy can be used for characterization of humic substances containing aromatic groups (phenoles, phenolates). For fluorescence measurement, Aminco Bowman Series 2 has been used for synchronous scan from 300 to 600 nm at room temperature. We have used optimal setting between monochromators (??=?em.-?ex.= 20 nm), slit width 4 nm. Dried samples of HA were dissolved in sodium hydroxide and samples of humates were dissolved in water. One standard sample of Leonardite humic acid (ordere from IHSS) has been used. Optimal concentration of HA or NaHA was 0,01 g/l. Samples have been measured in Suprasil cuvette (1 cm). The best resolution was achieved using synchronous fluorescence spectra. We have obtained spectra with main peak at about 488 nm, secondary peaks at 470, 500 and 510 nm, respectively. We have also studied the dependence of the intensity of fluorescence spectra on pH value. We have prepared aqueous humates solutions in pH range from 3 to 9. Spectral intensity was inflicted mostly at pH = 4.

humic acids, synchronous fluorescence spectroscopy, lignite

FASUROVÁ, N., ČECHLOVSKÁ, H.

2005

20. 9. 2005

česká společnost chemická

Praha

0009-2770

Chemické listy

99

1

Česká republika

566

567

2