Fluorescence quenching effects of antibiotics on the main components of dissolved organic matter

Abstract

Dissolved organic matter (DOM) in wastewater can be characterized using fluorescence excitation-emission matrix and parallel factor (EEM-PARAFAC) analysis. Wastewater from animal farms or pharmaceutical plants usually contains high concentration of antibiotics. In this study, the quenching effect of antibiotics on the typical components of DOM was explored using fluorescence EEM-PARAFAC analysis. Four antibiotics (roxarsone, sulfaquinoxaline sodium, oxytetracycline, and erythromycin) at the concentration of 0.5∼4.0 mg/L and three typical components of DOM (tyrosine, tryptophan, and humic acid) were selected. Fluorescence quenching effects were observed with the addition of antibiotics. Among these four antibiotics, roxarsone (2.9∼20.2 %), sulfaquinoxaline sodium (0∼32.0 %), and oxytetracycline (0∼41.8 %) led to a stronger quenching effect than erythromycin (0∼8.0 %). From the side of DOM, tyrosine and tryptophan (0.5∼41.8 %) exhibited a similar quenching effect, but they were higher than humic acids (0∼20.2 %) at the same concentration of antibiotics. For humic acid, a significant quenching effect was observed only with the addition of roxarsone. This might be the first report about the fluorescence quenching effect caused by antibiotics. The results from this study confirmed the interference of antibiotics on the fluorescence intensity of the main components of DOM and highlighted the importance of correcting fluorescence data in the wastewater containing antibiotics.

Transport of Veterinary Antibiotics in Farmland Soil: Effects of Dissolved Organic Matter

“…Spectroscopic methods have been extensively used for the chemical and structural characterisation of DOM due to their accuracy and ability to give a detailed molecular structure of DOM [44,115], and have shown much usefulness in elucidating the interactions between DOM and VAs, especially in water [29,31,32,81,89,116,117].…”

“…It reflects the carboxylic and aromatic chromophores of DOM based on the absorbance wavelength [113], and absorbance ratios such as A 254 /A 204 , A 254 /A 436 , and A 250 /A 365 are correlated with DOM reactive properties and thus valuable for DOM characterisation [31,113,119,120]. UV−VIS absorbance is often used together with a three-dimensional fluorescence excitation−emission matrix (3D-EEM) to comprehensively describe DOM−VA interactions [31,89,117].…”

“…Such a quenching process may lead to energy transfer or to the formation of a ground-state complex, which is commonly referred to as dynamic or static quenching, respectively [82,123]. Static quenching implies that DOM−VA binding or complexation leads to a significant decrease in freely dissolved VAs in soil, while dynamic quenching results from charge transfer that occurs when fluorophore and quencher collided [26,29,31,117]. The complexation and binding properties of DOM−VA interactions were found to be highly related to the proportion of DOM fluorescent components [31,117].…”

“…The interaction followed the order: tyrosine ≥ tryptophan > HA component. [117] Tetracycline and DOM − 5-50 mg L −1…”

“…The protein-like components of DOM can form strong binding interactions with VAs [24,82,127]. For example, compared to humic-like components, the protein-like (tyrosine and tryptophan) component of DOM from various sources binds more strongly with TCs, sulfamethazine, sulfaquinoxaline-sodium, oxytetracycline, and erythromycin, through multiple molecular binding sites accessible in this component [24,81,117]. As such, the fluorescence EEM spectroscopy technique has gained wide acceptance for studying DOM−VA interactions [24,81,114,115,[127][128][129][130].…”