Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry
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 hang...
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Online Access: | http://hdl.handle.net/11383/1806316 https://doi.org/10.1021/ac303621q |
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ftuninsubriairis:oai:irinsubria.uninsubria.it:11383/1806316 2024-04-14T08:20:03+00:00 Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry Laglera, L. M. Santos Echeandía, J. Caprara, S. MONTICELLI, DAMIANO Laglera, L. M. Santos Echeandía, J. Caprara, S. Monticelli, Damiano 2013 STAMPA http://hdl.handle.net/11383/1806316 https://doi.org/10.1021/ac303621q eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000315326900074 volume:85 issue:4 firstpage:2486 lastpage:2492 numberofpages:7 journal:ANALYTICAL CHEMISTRY http://hdl.handle.net/11383/1806316 doi:10.1021/ac303621q info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-84874024817 info:eu-repo/semantics/openAccess info:eu-repo/semantics/article 2013 ftuninsubriairis https://doi.org/10.1021/ac303621q 2024-03-21T18:58:52Z 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. Article in Journal/Newspaper Southern Ocean IRInSubria - Institutional Repository Insubria (Università degli Studi dell’Insubria) Southern Ocean Analytical Chemistry 85 4 2486 2492 |
institution |
Open Polar |
collection |
IRInSubria - Institutional Repository Insubria (Università degli Studi dell’Insubria) |
op_collection_id |
ftuninsubriairis |
language |
English |
description |
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. |
author2 |
Laglera, L. M. Santos Echeandía, J. Caprara, S. Monticelli, Damiano |
format |
Article in Journal/Newspaper |
author |
Laglera, L. M. Santos Echeandía, J. Caprara, S. MONTICELLI, DAMIANO |
spellingShingle |
Laglera, L. M. Santos Echeandía, J. Caprara, S. MONTICELLI, DAMIANO Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry |
author_facet |
Laglera, L. M. Santos Echeandía, J. Caprara, S. MONTICELLI, DAMIANO |
author_sort |
Laglera, L. M. |
title |
Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry |
title_short |
Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry |
title_full |
Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry |
title_fullStr |
Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry |
title_full_unstemmed |
Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry |
title_sort |
quantification of iron in seawater at the low picomolar range based on optimization of bromate/ammonia/dihydroxynaphtalene system by catalytic adsorptive cathodic stripping voltammetry |
publishDate |
2013 |
url |
http://hdl.handle.net/11383/1806316 https://doi.org/10.1021/ac303621q |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000315326900074 volume:85 issue:4 firstpage:2486 lastpage:2492 numberofpages:7 journal:ANALYTICAL CHEMISTRY http://hdl.handle.net/11383/1806316 doi:10.1021/ac303621q info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-84874024817 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1021/ac303621q |
container_title |
Analytical Chemistry |
container_volume |
85 |
container_issue |
4 |
container_start_page |
2486 |
op_container_end_page |
2492 |
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1796298227434127360 |