Analysis of the Cu<sup>2+</sup>-Soil Fulvic Acid Complexation by Anodic Stripping Voltammetry Using an Electrostatic Model

Carballeira, J.L.; Antelo, Juan; Arce, F.

doi:10.1021/es001036u

Cited by 17 publications

(10 citation statements)

References 17 publications

(23 reference statements)

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“…Electrolabile copper ion concentrations were measured by Differential Pulse Anodic Stripping Voltammetry (DPASV), using a Metrohm E-506 polarograph with a 663VA stand. As described in a previous paper (19) during the deposition step, a potential value far from the zero charge potential To avoid potential interference of oxygen with the voltammetric measurements, a stream of nitrogen was used for an optimum intervale of 10 min (20). After each addition of titrant, the CO2/N2 stream used to adjust the pH also effectively removed oxygen from the solution.…”

Section: Methodsmentioning

confidence: 99%

Analysis of the Effect of pH on Cu²⁺−Fulvic Acid Complexation Using a Simple Electrostatic Model

Ramos

Fiol

López

et al. 2002

Environ. Sci. Technol.

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A simple electrostatic model was used to study the effect of pH on the binding of Cu2+ to fulvic acid in solutions containing similar amounts of dissolved organic carbon (DOC) as natural media, such as aquatic environments and soil solutions. Complexation behavior was affected by increased pH because of changes in the electrostatic interaction resulting from an increase in the negative charge on the fulvic acid molecule. Solutions of soil-extracted fulvic acid (FA), at concentrations of 25 and 35 mg L(-1), ionic strength 0.005 M, and pH 5.0, 5.5, 6.0, 6.5, 7.0, and 7.5, conditions that simulate those of natural freshwaters, were titrated with copper ion using differential pulse anodic stripping voltammetry. Assuming the formation of 1:1 complexes, the conditional binding parameters (stability constant and binding capacity) were calculated for each pH value. Use of a 1:1 electrostatic model allowed estimation of the contribution of the electrostatic effect to the ion binding reaction, at each pH value, as well as calculation of a binding constant that was not dependent on pH and which thus represented the contribution of the chemical heterogeneity. Furthermore, it was found that only a small proportion of the FA acid functional binding sites are involved in the formation of copper complexes.

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Section: Methodsmentioning

confidence: 99%

Analysis of the Effect of pH on Cu²⁺−Fulvic Acid Complexation Using a Simple Electrostatic Model

Ramos

Fiol

López

et al. 2002

Environ. Sci. Technol.

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“…The key techniques in these studies include: the ion selective electrode method [ 14 , 15 ], voltammetry [ 16 , 17 , 18 ], potentiometric titration [ 19 ], and three-dimensional fluorescence spectroscopy [ 20 , 21 ]. Among these methods, fluorescence quenching turned out to be an accurate method for analyzing the interactions between contaminants and HA, as it is not limited by extraction, purification, or other physical treatments [ 22 , 23 ] and can directly measure changes in fluorescence intensity before and after the action of humic substances and contaminants, to obtain parameters such as the binding constant.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, people are also increasingly concerned about the environmental behavior of antibiotics with humus coexistence. Currently, the use of three-dimensional fluorescence spectroscopy to study the interaction between substances is mainly focused on the interaction of humic substances with heavy metals and hydrophobic organics [ 14 , 17 , 18 , 21 ]. Therefore, the use of three-dimensional fluorescence spectroscopy to study the role of humus and different types of antibiotics is of great significance for understanding the mechanism of humus and antibiotics in a water environment and its migration and transformation patterns.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the Interaction between Antibiotics and Humic Acid by Fluorescence Quenching Method

Wang

Yang

Fang

et al. 2018

IJERPH

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The method of Three-Dimensional Excitation Emission Matrix Fluorescence Spectrophotometer was used to identify the interaction mechanism between humic acid (HA) and antibiotics. The effects of antibiotic concentration, temperature, and pH on the bonding strength between HA and antibiotics were investigated. The results showed that with the increase of antibiotics concentration, the quenching effect on HA was enhanced. The quenching of HA by both oxytetracycline (OTC) and sulfadiazine (SD) is a single static quenching of the complexes, and the interaction forces are mainly a hydrogen bond and the van der Waals force. The quenching constant KsvOTC > KsvSD and the binding constant KbOTC > KbSD, indicates that HA has a more obvious quenching effect on OTC. The Kb of HA by OTC ranged from 3.223 × 103 to 12.784 × 103 L·mol−1 in the range of 298 K to 313 K, while the Kb of HA by SD ranged from 2.051 × 103 to 5.533 × 103 L·mol−1. With the increase of temperature, the quenching constant Ksv and binding constant Kb of both OTC and SD by HA gradually decrease, and the low temperature is beneficial to the interaction. The composite of OTC and HA is more stable than SD. Under neutral alkaline conditions, both OTC and SD had the strongest quenching effect on HA, and the resulting complex was the most stable. However, the Ksv and Kb of HA by OTC were greater than SD in the pH range of the experiment and the pH effect on quenching of HA by OTC (Ksv) was greater than that of SD.

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“…The methods used to investigate the intercctions between humus and contaminants include potentiometric titration [ 21 ], voltammetry [ 22 , 23 ] and ion selective electrode methods [ 24 , 25 ]. Compared with these methods, the ultraviolet visible spectrum method is simple to operate, less destructive to the sample and less demanding, and the specific wavelength of the UV visible absorption ratio (E4/E6) is often used to indicate the structural changes of humus [ 26 ], which can provide information about humus molecules.…”

Section: Introductionmentioning

confidence: 99%

Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry

Yuan

Yang

Fang

et al. 2018

IJERPH

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In this study, the interaction between the humus and two antibiotics was studied by UV-Vis spectroscopy to describe the interaction mechanism and the effects of different environmental factors on the mechanism. Results showed that humic acid (HA) containing more aromatic groups was easily associated with antibiotics. In the HA-OTC, with the increase of the concentration of OTC, there were obvious absorption peaks in the 230–260 nm and 330–360 nm range, and the absorption band of the HA ultraviolet spectrum underwent a slight blue shift and the absorption intensity increased, demonstrating that a new ground state complex was generated. In the HA-SD, with the increase of SD concentration, an aromatic structure absorption peak appeared in the 190–220 nm range, and the peak value increased and the absorption band underwent a red shift, and the aromatization of HA decreased, which enhanced the interaction between the antibiotics and HA. With the increase of pH, the absorption band of HA, HA-OTC and HA-SD ultraviolet spectrum suffered a blue shift, the degree of polymerization of HA molecules decreased, and the number of adsorption binding sites increased, which resulted in the interaction of HA with antibiotics being enhanced. The absorption band of HA, HA-OTC and HA-SD displayed a red shift with the increase of ionic strength, which indicated that the repulsion within HA particles was weakened, and the molecular polymerization was strengthened and therefore, the interaction between antibiotics and HA was inhibited. The UV characteristics of the HA, HA-OTC and HA-SD systems were insensitive to the temperature. This study lays the foundation for better studying the effect of humus on the distribution of antibiotic residues in the environment.

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Analysis of the Cu²⁺-Soil Fulvic Acid Complexation by Anodic Stripping Voltammetry Using an Electrostatic Model

Cited by 17 publications

References 17 publications

Analysis of the Effect of pH on Cu²⁺−Fulvic Acid Complexation Using a Simple Electrostatic Model

Analysis of the Effect of pH on Cu²⁺−Fulvic Acid Complexation Using a Simple Electrostatic Model

Characterizing the Interaction between Antibiotics and Humic Acid by Fluorescence Quenching Method

Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry

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Analysis of the Cu2+-Soil Fulvic Acid Complexation by Anodic Stripping Voltammetry Using an Electrostatic Model

Cited by 17 publications

References 17 publications

Analysis of the Effect of pH on Cu2+−Fulvic Acid Complexation Using a Simple Electrostatic Model

Analysis of the Effect of pH on Cu2+−Fulvic Acid Complexation Using a Simple Electrostatic Model

Characterizing the Interaction between Antibiotics and Humic Acid by Fluorescence Quenching Method

Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry

Contact Info

Product

Resources

About

Analysis of the Cu²⁺-Soil Fulvic Acid Complexation by Anodic Stripping Voltammetry Using an Electrostatic Model

Analysis of the Effect of pH on Cu²⁺−Fulvic Acid Complexation Using a Simple Electrostatic Model

Analysis of the Effect of pH on Cu²⁺−Fulvic Acid Complexation Using a Simple Electrostatic Model