Quantification of iron in seawater at the low picomolar range based on the optimization of the bromate-ammonia-dihydroxynaphtalene system by catalytic adsorptive cathodic stripping voltammetry

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dc.contributor.author Laglera Baquer, Luis Miguel
dc.contributor.author Santos Echeandía, Juan
dc.contributor.author Caprara, Salvatore
dc.contributor.author Monticelli, Damiano
dc.date.accessioned 2018-09-25T11:59:28Z
dc.identifier.uri http://hdl.handle.net/11201/147668
dc.description.abstract [eng] A new analytical protocol for the challenging analysis of total dissolved iron at the low picomolar level in oceanic waters suitable for onboard analysis is presented. The method is based on the revision of the adsorptive properties of the iron/2,3-dihydroxynaphthalene (Fe/DHN) complexes on the hanging mercury drop electrode with catalytic enhancement by bromate ions. Although it was based on a previously proposed reagent combination, we show here that the addition of an acidification/alkalinization step is essential in order to cancel any organic complexation, and that an extra increment of the pH to 8.6−8.8 leads to the definition of a preconcentration-free procedure with the lowest detection limit described up to now. For total dissolved iron analysis, samples were acidified to pH 2.0 in the presence of 30 μM DHN and left to equilibrate overnight. A 10 mL sample was subsequently buffered to a pH of ∼8.7 in the presence of 20 mM bromate: a 60 s deposition at 0 V led to a sensitivity of 34 nA nM−1 min−1, a 4-fold improvement over previous methods, that translated in a limit of detection of 5 pM (2−20 fold improvement). Several tests proved that a nonreversible reaction in the time scale of the analysis, triggered by the acidification/alkalinization step, was behind the signal magnification. The new method was validated onboard via the analysis of reference material and via intercalibration against flow injection analysis-chemiluminescence on Southern Ocean surface samples.
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dc.relation.isformatof Versió postprint del document publicat a:
dc.relation.ispartof Analytical Chemistry, 2013, vol. 85, num. 4, p. 2486-2492
dc.subject.classification 54 - Química
dc.subject.other 54 - Chemistry. Crystallography. Mineralogy
dc.title Quantification of iron in seawater at the low picomolar range based on the optimization of the bromate-ammonia-dihydroxynaphtalene system by catalytic adsorptive cathodic stripping voltammetry
dc.type info:eu-repo/semantics/article
dc.type info:eu-repo/semantics/acceptedVersion
dc.date.updated 2018-09-25T11:59:28Z
dc.date.embargoEndDate info:eu-repo/date/embargoEnd/2075-01-01
dc.embargo 2075-01-01
dc.rights.accessRights info:eu-repo/semantics/embargoedAccess


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