Studium interakce huminových kyselin s léčivy a pesticidy

Abstract

The thesis deals with the interactions of humic acids (HA) from lignite and dark peat (TR) extracted with NaOH or piperidine with selected micropollutants (caffeine, paracetamol and metazachlor) by surface plasmon resonance imaging (SPRi). The extracted humic acids were fractionated and their physicochemical properties were studied. The extracted HAs were determined for extraction yield, particle size distribution, zeta potential, and FTIR-spectroscopic analysis was performed. For the study of interactions by the SPRi method, a biochip was designed, prepared and tested to enable the determination of association and dissociation constants of the interaction of micropollutants with HA fractions in real time. It was found that the fraction obtained at pH 2-4 for both lignite and TR exhibited the highest yield of HA extracted with NaOH, while the fraction obtained at pH 4-5 for lignite and pH 2-4 for TR exhibited the highest yield in piperidine. The particle size determination showed a relatively large heterogeneity of humic acids. The particle size for all fractions was < 400 nm. The zeta potential was in the negative region in the range of approximately -20 to - 50 mV for both lignite– and TR-derived fractions. The functional groups of HA that could play a role in the interaction with micropollutants were determined using FTIR spectroscopy. The main absorption bands for lignite and TR were in the region around 1443, 1383, 1628, 1717 cm-1, belonging to the COO- group. The KA association constants for lignite and dark peat were in the range of 30-1180 l mol-1. The association and dissociation rate constants took values in the range of 1-90 l mol-1 s-1 for ka a 3·10-2-9·10-2 s-1 pro kd. The degree of interaction depended on the specific micropollutant as well as on the HK fraction, the extraction reagent, and the source material from which the HA s were extracted.