Copper(II) complexing capacities of natural waters by fluorescence quenching

Ryan, David K.; Weber, James H.

doi:10.1021/es00106a009

Cited by 113 publications

(77 citation statements)

References 18 publications

(39 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This has also been obtained by Ryan and Weber (1982b), when using the one binding site model. The authors justify such behaviour as a consequence of some artifact of the model.…”

Section: Resultssupporting

confidence: 59%

The complexation of marine and terrestrial organic materials with copper (II) ions as determined by fluorescence quenching

Lombardi

Jardim

1997

Chemical Speciation & Bioavailability

View full text Add to dashboard Cite

Copper complexation parameters, e.g., conditional stability constant (K') and ligand concentration (CL), were obtained for marine DOM and soil fulvic acid (SFA). Complexometric titrations using Cu(ll) as the titrant were monitored by fluorescence quenching and data treatment was performed using a two-binding site model. The marine DOM was isolated by partitioning onto tC18 Sep-Pak cartridges and followed by a reverse phase-high performance liquid chromatography fractionation. The SFA was investigated before and after receiving the same treatment as the marine sample. The results show that there is a loss of ligands with high affinity for copper as a result of the Sep-Pak treatment on the SFA. The Sep-Pak processed SFA ligands are associated with fluorophores with excitation wavelength at 350 nm. The more polar chromatographic fractions have higher values of CUTOC, obeying a linear relation. A linear relation was also observed between total quenching (1 00-IMJ and normalised CL values (CUTOC).

show abstract

“…This has also been obtained by Ryan and Weber (1982b), when using the one binding site model. The authors justify such behaviour as a consequence of some artifact of the model.…”

Section: Resultssupporting

confidence: 59%

The complexation of marine and terrestrial organic materials with copper (II) ions as determined by fluorescence quenching

Lombardi

Jardim

1997

Chemical Speciation & Bioavailability

View full text Add to dashboard Cite

show abstract

“…The fraction of the free metal ion hydrolyzed is constant at constant pH and is therefore easily accounted for. A more quantitative treatment has been given previously (6).…”

Section: Resultsmentioning

confidence: 99%

Comparison of Mn²⁺, Co²⁺, and Cu²⁺ binding to fulvic acid as measured by fluorescence quenching

Ryan¹,

Thompson²,

Weber³

1983

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

The binding of Cu2+ to soil-derived fulvic acid (SFA) measured by fluorescence quenching titration is much stronger than Co2+ and Mn2+ which are similar. The conditional stability constants from curve fitting at pH 6 are 1.1 × 105 for Cu2+, 5.1 × 103 for Co2+, and 4.2 × 103 for Mn2+. The slight advantage in strength for Co2+ over Mn2+ is also demonstrated by the binding curves at pH 6 and 7. These two metal ions not only tend to bind more weakly but also bind to fewer sites, giving complexing capacity values of about 1.5 × 10−6 M compared to 2.0 × 10−5 for Cu2+ at pH 6. This lower binding capacity may be due to outer sphere complexation that does not allow access to some sites complexed by inner sphere binding Cu2+. Scattering experiments demonstrate that Cu2+ is more effective at precipitating and aggregating SFA than Co2+ and Mn2+. Cu2+ probably neutralizes the negative charges on SFA molecules allowing larger hydrophobic aggregates to form and precipitate.

show abstract

“…11 Considering this, fluorescence techniques are unique among metal-complexing methods in that they measure only the organic matter that changes with complexation rather than measuring free or labile metal species. [11][12][13] Thus, fluorescence measurements provide data that are complementary to ISE results or data from methods that measure free metal ions in equilibrium with DOM. 14 Fluorescence spectroscopy has been widely applied to molecular studies on DOM due to the presence of fluorescent material in this complex mixture of organic compounds.…”

Section: Introductionmentioning

confidence: 99%

“…16 Trace metal complexation with DOM has been previously measured through the fluorescence quenching technique. [11][12][13][14][15][16] This technique is sensitive to low concentrations of organic matter, and thus is suitable for use under natural conditions. 17 The binding of paramagnetic metal ions, such as Cu 2+ , Ni 2+ , and Co 2+ to natural organic matter results in the quenching of its fluorescence.…”

Section: Introductionmentioning

confidence: 99%

“…[20][21][22] Quenching techniques for the study of copper-DOM interactions were first applied using the fluorescence emission spectra. 11,12 However, it is possible to obtain spectra that are significantly more valuable when excitation and emission wavelengths are allowed to vary simultaneously. 23 Synchronous fluorescence (SyF) has been reported to have several advantages over conventional fluorescence emission spectroscopy in studying natural organic matter.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of anthropogenic influences on copper complexation by aquatic dissolved organic matter using synchronous fluorescence

Sodré¹,

Grassi²

2007

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Neste trabalho foi avaliada a influência das atividades antrópicas sobre as características da matéria orgânica dissolvida (MOD) aquática empregando-se fluorescência sincronizada (SyF). Amostras dos rios Iraí e Iguaçu foram coletadas em pontos localizados à montante e à jusante de uma região urbanizada, respectivamente, durante o inverno e o verão. A MOD das amostras foi analisada por SyF, titulada com Cu 2+ e os dados gerados foram tratados com um modelo não linear em, pelo menos, cinco regiões espectrais. Os resultados mostraram que durante o verão, o período de maior pluviosidade, a MOD de ambos os rios apresentou estruturas orgânicas simples tais como aminoácidos aromáticos e/ou compostos alifáticos conjugados como constituintes majoritários, surgidos, provavelmente, a partir de fontes difusas. Durante o inverno foi possível evidenciar que o aporte de esgoto bruto a partir da região urbanizada contribuiu para o aumento de MOD fluorescente incapaz de complexar o cobre.Anthropogenic influences on the characteristics of aquatic dissolved organic matter (DOM) were evaluated in this work using synchronous fluorescence (SyF) scan spectroscopy. Samples from the Iraí and the Iguaçu Rivers were collected during the summer and winter at points located upstream and downstream from a heavily urbanized area in Brazil, respectively. DOM from all samples was titrated with Cu 2+ and monitored by SyF quenching. A 1:1 non linear model was used for data treatment in, at least, five distinct regions of the spectra. Results revealed that during the rainy summer, DOM from both rivers exhibited simple organic structures such as aromatic amino acids or conjugated aliphatics as the major constituents, probably arising from non-point sources. However, during the dry winter it became clear that raw sewage discharges arising from the urbanized area contributed to an increase of fluorescent organic matter that is unable to complex copper.Keywords: synchronous fluorescence, dissolved organic matter, fluorescence quenching, copper complexation, raw sewage discharges IntroductionOrganic matter is an important component responsible for several chemical and biological processes in natural waters.1 Furthermore, dissolved organic matter (DOM) is known to play a key role on copper speciation in aquatic environments.2 Many investigations have shown that in its free or labile form, copper can be toxic to aquatic biota. This toxicity can be moderated or even completely eliminated through copper complexation by selected functional groups occurring in the DOM. 4 The chemical significance of the DOM at a given place is determined by its chemical nature. The diversity and variability of organic materials within a specific stream are mostly dependent on the potential sources of carbon.5 These sources can arise from in-stream processes (autochthonous sources) or from external ones (allochthonous sources) such as leachate from surrounding soils, stormwater runoff as well as from treated or raw sewage discharges.6 Thus, it is expected that not all organic...

show abstract

Copper(II) complexing capacities of natural waters by fluorescence quenching

Cited by 113 publications

References 18 publications

The complexation of marine and terrestrial organic materials with copper (II) ions as determined by fluorescence quenching

The complexation of marine and terrestrial organic materials with copper (II) ions as determined by fluorescence quenching

Comparison of Mn²⁺, Co²⁺, and Cu²⁺ binding to fulvic acid as measured by fluorescence quenching

Assessment of anthropogenic influences on copper complexation by aquatic dissolved organic matter using synchronous fluorescence

Contact Info

Product

Resources

About

Copper(II) complexing capacities of natural waters by fluorescence quenching

Cited by 113 publications

References 18 publications

The complexation of marine and terrestrial organic materials with copper (II) ions as determined by fluorescence quenching

The complexation of marine and terrestrial organic materials with copper (II) ions as determined by fluorescence quenching

Comparison of Mn2+, Co2+, and Cu2+ binding to fulvic acid as measured by fluorescence quenching

Assessment of anthropogenic influences on copper complexation by aquatic dissolved organic matter using synchronous fluorescence

Contact Info

Product

Resources

About

Comparison of Mn²⁺, Co²⁺, and Cu²⁺ binding to fulvic acid as measured by fluorescence quenching