Determination of iron and copper in seawater at pH 1.7 with a new commercially available chelating resin, NTA Superflow

Lohan, Maeve C.; Aguilar-Islas, Ana M.; Franks, Robert P.; Bruland, Kenneth W.

doi:10.1016/j.aca.2004.09.005

Cited by 106 publications

(84 citation statements)

References 33 publications

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“…The method analyses Fe(III), therefore hydrogen peroxide (Merck suprapur 30%) solution was added (60 ml of a 1%) at least 1 h before analysis to ensure oxidation of the Fe(II) present (Lohan et al, 2005). The acidified samples were preconcentrated over a Toyopearl AFChelate 650 M (TesoHaas Germany) column during 120 s. Subsequently the column was rinsed with MQ for 60 s, after which Fe was eluted with 0.4 M HCl (Suprapur, Merck) for 120 s and injected in the photon counter (Hamamatsu HC 135).…”

Section: Iron Analysesmentioning

confidence: 99%

Speciation of Fe in the Eastern North Atlantic Ocean

Thuroczy

Gerringa

Klunder

et al. 2010

Deep Sea Research Part I: Oceanographic Research Papers

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a b s t r a c tIn the Eastern North Atlantic Ocean iron (Fe) speciation was investigated in three size fractions: the dissolvable from unfiltered samples, the dissolved fraction (o 0.2 mm) and the fraction smaller than 1000 kDa ( o 1000 kDa). Fe concentrations were measured by flow injection analysis and the organic Fe complexation by voltammetry. In the research area the water column consisted of North Atlantic Central Water (NACW), below which Mediterranean Overflow Water (MOW) was found with the core between 800 and 1000 m depth. Below 2000 m depth the North Atlantic Deep Water (NADW) proper was recognised. Dissolved Fe and Fe in the o 1000 kDa fraction showed a nutrient like profile, depleted at the surface, increasing until 500-1000 m depth below which the concentration remained constant. Fe in unfiltered samples clearly showed the MOW with high concentrations (4 nM) compared to the overlying NACW and the underlying NADW, with 0.9 nM and 2 nM Fe, respectively. By using excess ligand (Excess L) concentrations as parameter we show a potential to bind Fe. The surface mixed layer had the highest excess ligand concentrations in all size fractions due to phytoplankton uptake and possible ligand production. The ratio of Excess L over Fe proved to be a complementary tool in revealing the relative saturation state of the ligands with Fe. In the whole water column, the organic ligands in the larger colloidal fraction (between 0.2 mm and 1000 kDa) were saturated with Fe, whereas those in the smallest fraction ( o1000 kDa) were not saturated with Fe, confirming that this fraction was the most reactive one and regulates dissolution and colloid aggregation and scavenging processes. This regulation was remarkably stable with depth since the alpha factor (product of Excess L and K 0 ), expressing the reactivity of the ligands, did not vary and was 10 13 . Whereas, in the NACW and the MOW, the ligands in the particulate (4 0.2 mm) fraction were unsaturated with Fe with respect to the dissolved fraction, thus these waters had a scavenging potential.Crown

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Section: Iron Analysesmentioning

confidence: 99%

Speciation of Fe in the Eastern North Atlantic Ocean

Thuroczy

Gerringa

Klunder

et al. 2010

Deep Sea Research Part I: Oceanographic Research Papers

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“…Therefore, to make a measurement of "total" copper consistent with the operational definition used by other researchers (Sunda and Huntsman 1991;Coale et al 1992;Morel and Hering 1993), the sample stream is acidified inline to a pH of ~1.7. We chose to acidify samples to pH < 2 to be consistent with conventional methods of trace metal analysis where acidification to this level is necessary, at least for the analysis of total dissolved iron (Lohan et al 2005). Acidification to pH 2-3 may be sufficient for copper but was not tested in this study.…”

Section: Materials and Proceduresmentioning

confidence: 99%

Development and initial deployments of an autonomous in situ instrument for long‐term monitoring of copper (II) in the marine environment

Holm

Chase

Jannasch

et al. 2008

Limnology & Ocean Methods

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We developed an autonomous, in situ instrument to detect dissolved copper in seawater, suitable for deployment on time scales from weeks to a month. A commercially available in situ nitrate analyzer (YSI 9600) was adapted to measure copper (II) by chemiluminescence. Modifications included construction of a photomultiplier (PMT)-based detector and flow-cell, the use of more chemically resistant plastics for parts in contact with the reagents, addition of an online acidification step, and optimization of the method and flow parameters. Microsolenoid pumps take in sample and dispense reagent, standard, and blank solutions, which are stored in 1 L plastic bags. Filtration (0.45 μm) and acidification (pH ~1.7) permit a measurement of total dissolved Cu(II). Calibration is achieved by periodically analyzing ligand-stabilized seawater standard and blank solutions stored at pH 8 and acidified online. Averaged over all in situ deployments, the instrument had a detection limit of 0.8 ± 0.3 nM, a sample precision of 11% (n = 612), and an accuracy of 17% (compared to discrete samples n = 27). The instrument is capable of functioning autonomously for 25 d when sampling every hour and calibrating every 6 h. Reagent consumption is the limiting factor.

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“…In the case of iron analysis in seawaters, matrix effects and low concentration levels are the main difficulties. To overcome these difficulties and to increase the sensitivity, separation and/or preconcentration of the analyte is often necessary (Lohan et al 2005) in spectrophotometric methods.…”

Section: Introductionmentioning

confidence: 99%

Sequential injection trace determination of iron in natural waters using a long‐pathlength liquid core waveguide and different spectrophotometric chemistries

Páscoa

Tóth

Rangel

2009

Limnology & Ocean Methods

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We developed a sequential injection analysis (SIA) method for the determination of iron in coastal, ground, and surface fresh waters using two different reagents (ferrozine and 1,10-phenathroline). The methodology uses a double-line SIA system to improve mixing conditions between sample and reagent solutions. A liquid waveguide capillary cell (LWCC) with 1.0 m pathlength, 550 µm i.d., and 250 µL internal volume was used to enhance the sensitivity of the determination. The detection limits for the ferrozine and 1,10-phenanthroline reagent were 0.15 and 0.35 µg L -1 , respectively. The system provides a linear response up to 20 µg L -1 and has a high throughput rate (41 h -1 ), low reagent consumption, and also low effluent production for both reagents. The developed method was applied to natural waters (river, well, ground, potable, and sea waters) and one reference water sample.

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Determination of iron and copper in seawater at pH 1.7 with a new commercially available chelating resin, NTA Superflow

Cited by 106 publications

References 33 publications

Speciation of Fe in the Eastern North Atlantic Ocean

Speciation of Fe in the Eastern North Atlantic Ocean

Development and initial deployments of an autonomous in situ instrument for long‐term monitoring of copper (II) in the marine environment

Sequential injection trace determination of iron in natural waters using a long‐pathlength liquid core waveguide and different spectrophotometric chemistries

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