The determination of trace levels of iron in seawater, using adsorptive cathodic stripping voltammetry

Berg, Christopher M.; Nimmo, Malcolm; Abollino, Ornella; Mentasti, Edoar̈do

doi:10.1002/elan.1140030606

Cited by 52 publications

(9 citation statements)

References 13 publications

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“…Media were sterilized by microwaving 4 times at 1200 W, 3 min each time (Keller et al 1988). In media without added iron ('ironfree media'), concentrations of iron were undetectable (≤1 nM) by electrochemical methods (Van den Berg et al 1991).…”

Section: Abstract: Fe Limitation · Inorganic N Assimilation · Growthmentioning

confidence: 99%

Regulation of growth and energetics of a marine bacterium by nitrogen source and iron availability

Kirchman¹,

Hoffman²,

Weaver³

et al. 2003

Mar. Ecol. Prog. Ser.

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Section: Abstract: Fe Limitation · Inorganic N Assimilation · Growthmentioning

confidence: 99%

Regulation of growth and energetics of a marine bacterium by nitrogen source and iron availability

Kirchman¹,

Hoffman²,

Weaver³

et al. 2003

Mar. Ecol. Prog. Ser.

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“…Van den Berg et al (1991) described an electrochemical method for measuring chelateable iron using the chelate 1-nitroso-2-naphthol (1-N-2-N). Wu and Luther (1994) used cathodic stripping square wave voltammetry to increase the sensitivity of Van den Berg's method allowing measurements of 'chelateable' iron in operationally defined dissolved (0.4/,m) and particulate fractions.…”

Section: Fe Availabilitymentioning

confidence: 99%

The role of iron in phytoplankton photosynthesis, and the potential for iron-limitation of primary productivity in the sea

1994

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Iron supply has been suggested to influence phytoplankton biomass, growth rate and species composition, as well as primary productivity in both high and low NO3 (-) surface waters. Recent investigations in the equatorial Pacific suggest that no single factor regulates primary productivity. Rather, an interplay of bottom-up (i.e., ecophysiological) and top-down (i.e., ecological) factors appear to control species composition and growth rates. One goal of biological oceanography is to isolate the effects of single factors from this multiplicity of interactions, and to identify the factors with a disproportionate impact. Unfortunately, our tools, with several notable exceptions, have been largely inadequate to the task. In particular, the standard technique of nutrient addition bioassays cannot be undertaken without introducing artifacts. These so-called 'bottle effects' include reducing turbulence, isolating the enclosed sample from nutrient resupply and grazing, trapping the isolated sample at a fixed position within the water column and thus removing it from vertical movement through a light gradient, and exposing the sample to potentially stimulatory or inhibitory substances on the enclosure walls. The problem faced by all users of enrichment experiments is to separate the effects of controlled nutrient additions from uncontrolled changes in other environmental and ecological factors. To overcome these limitations, oceanographers have sought physiological or molecular indices to diagnose nutrient limitation in natural samples. These indices are often based on reductions in the abundance of photosynthetic and other catalysts, or on changes in the efficiency of these catalysts. Reductions in photosynthetic efficiency often accompany nutrient limitation either because of accumulation of damage, or impairment of the ability to synthesize fully functional macromolecular assemblages. Many catalysts involved in electron transfer and reductive biosyntheses contain iron, and the abundances of most of these catalysts decline under iron-limited conditions. Reductions of ferredoxin or cytochrome f content, nitrate assimilation rates, and dinitrogen fixation rates are amongst the diagnostics that have been used to infer iron limitation in some marine systems. An alternative approach to diagnosing iron-limitation uses molecules whose abundance increases in response to iron-limitation. These include cell surface iron-transport proteins, and the electron transfer protein flavodoxin which replaces the Fe-S protein ferredoxin in many Fe-deficient algae and cyanobacteria.

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“…1-nitroso-2-naphthol (hereafter referred to as NN) is a hydrophobic metal chelator with a nitroso-and a hydroxyl group. Due to its ability to form strong, electroactive 1:3 complexes with Fe it is used for the determination of free (Van den Berg et al, 1991) and organically bound (Wu and Luther, 1995;Hawkes et al, 2013) Fe in natural water samples via adsorptive cathodic stripping voltammetry (ACSV) and CLE-ACSV, respectively. Salicylaldoxime (SA), a salicylaldehyde oxime, is a chelator with an oxime and a hydroxyl functional group which forms 1:1 and 1:2 complexes with Cu and Fe, and is routinely used in the determination of Fe-and Cucomplexing capacities of DOM in natural water samples via CLE-ACSV (Campos and van den Berg, 1994;Rue and Bruland, 1995).…”

Section: Introductionmentioning

confidence: 99%

Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

2016

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In recent years, electrospray-ionization mass spectrometry (ESI-MS) has been increasingly used to complement the bulk determination of metal-ligand equilibria, for example via competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV). However, ESI-MS speciation analyses may be impacted by instrumental artifacts such as reduction reactions, fragmentation, and adduct formation at the ESI source, changes in the ionization efficiencies of the detected species in relation to sample matrix, and peak overlaps in response to increasing sample complexity. In our study, equilibria of the known artificial ligands citrate, ethylenediaminetetraacetic acid (EDTA), 1-nitroso-2-naphthol (NN), and salicylaldoxime (SA) with iron (Fe) and copper (Cu) were investigated by ultra-high resolution ESI-MS, Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), under a variety of sample matrix and ionization settings. The acquired mass spectra were compared with metal-ligand equilibrium data from the literature as well as an adapted speciation model. Overall, the mass spectra produced representative species mentioned in previous reports and predicted by the speciation calculations, such as Fe(Cit), Cu(Cit) 2 , Fe(EDTA), Cu(EDTA), Fe(NN) 3 , and Cu(SA) 2 . The analyses furthermore revealed new species which had been hypothesized but not measured directly using other methods, for example ternary complexes of citrate with Fe and Cu, Cu(SA) monomers, and the dimer Fe(SA) 2 . Finally, parallel measurements of a Cu+SA calibration series and a Cu+SA+EDTA competition series indicated that FT-ICR-MS can produce linear responses and low detection limits analogous to those of ACSV. We propose that ultra-high resolution FT-ICR-MS can be used as a representative tool to study interactions of trace metals with artificial as well as natural, unknown ligands at the molecular level.

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The determination of trace levels of iron in seawater, using adsorptive cathodic stripping voltammetry

Cited by 52 publications

References 13 publications

Regulation of growth and energetics of a marine bacterium by nitrogen source and iron availability

Regulation of growth and energetics of a marine bacterium by nitrogen source and iron availability

The role of iron in phytoplankton photosynthesis, and the potential for iron-limitation of primary productivity in the sea

Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

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