THE USE OF FLUORESCENCE SPECTROSCOPY TO STUDY HERBICIDE-HUMIC ACID INTERACTIONS: PRELIMINARY OBSERVATIONS

Fluorescence spectroscopy was used to study the interaction of humic acid with Cu +2 , paraquat and simetryn. Paraquat and Cu +2 quenched the fluorescence of humic acid (HA) by as much as 74 and 89%, respectively. Simetryn did not quench the fluorescence of HA, even at pH 4 under which conditions simetryn would have carried a positive charge due to protonation. Key words: Fluorescence spectroscopy, simetryn, paraquat, copper, humic acid