Matches in SemOpenAlex for { <https://semopenalex.org/work/W2152607368> ?p ?o ?g. }
- W2152607368 endingPage "74" @default.
- W2152607368 startingPage "60" @default.
- W2152607368 abstract "The chemical speciation of iron in seawater is typically determined by cathodic stripping voltammetry (CSV) making use of ligand competition between an electroactive ligand added to obtain the CSV signal and the natural ligand to determine the complex stability of the natural species. Different procedures differ in the added ligand that is selected. Recent findings have suggested that several of these procedures suffer from interference by humic substances , which are now known to be ubiquitous in coastal and ocean waters. We re-optimise here CSV of iron speciation using salicylaldoxime (SA) in seawater, finding differences with the pre-existing method, and a different interpretation for the electroactive species. The main findings are that optimum sensitivity is obtained at ~ 5 × less SA, that the complex responsible for adsorption on the electrode is FeSA, that the FeSA 2 species does not adsorb, and that the sensitivity of the method is much improved in the presence of dissolved oxygen (DO) through a catalytic effect (Fe II acts as catalyst for the reduction of DO). The complex stability for complexes of Fe′ with SA (FeSA and FeSA 2 ), in pH 8 seawater, is calibrated over a range of SA concentrations between 1 and 40 μM SA against EDTA and between 1 and 100 μM SA without EDTA. Data fitting of the EDTA data gave log K′ Fe′SA = 6.50 ± 0.04 and log B′ Fe′SA2 = 10.85 ± 0.08. The data fits agree with the formation of an electroactive species FeSA which is superseded by a non-electroactive FeSA 2 at [SA] > 5 μM. Independent calibration of these stability constants on the basis of the formation of FeSA in competition only with the hydroxide species of Fe III , between 1 and 100 μM SA, without EDTA, gave values of log K′ Fe′SA = 6.52 ± 0.01 and log B′ Fe′SA2 = 10.72 ± 0.03. These are the values we propose for the constants as they are independent of any uncertainties in the speciation with EDTA. The similarity of these constants to those determined via calibration against EDTA shows that the speciation of Fe with SA and EDTA is well understood. The re-optimised method is applied to a mixed depth Celtic Sea sample, and two GEOTRACES samples from the Atlantic, at a SA concentration of 5 μM. Ligand concentrations were 1.47 and 1.49 nM in the GEOTRACES water (log K′ Fe′L values of 11.1 and 11.9) and 2.53 nM in the Celtic Sea water (log K′ Fe′L = 11.5). Application of the method to ligands added to seawater gave log K′ Fe′L values of 11.6 ± 0.1 for humic acid (Suwannee River) and 12.2 ± 0.3 for a siderophore (desferrioxamine B). Measurement of the rate of dissociation of the complex of Fe with the natural ligand in Celtic seawater gave a value of k FeL = 0.00133 ± 0.0002 s − 1 . The half-life of this reaction is 8.7 minutes. This means that a reaction time of 1 h is required after the addition of SA prior to analysis. • We optimize here a method to determine the chemical speciation of iron in seawater • The experiments indicate that FeSA is the species that adsorbs on the electrode • LogK′ Fe′SA is 6.52 and log B′ Fe′SA2 = 10.72 for SA between 1 and 100 μM SA, with α Fe′SA between 3 and 856 • The sensitivity for iron is catalytically enhanced 10-fold by dissolved oxygen • Log K values are distinct for ligands in seawater, humics and a siderophore" @default.
- W2152607368 created "2016-06-24" @default.
- W2152607368 creator A5023076826 @default.
- W2152607368 creator A5054242625 @default.
- W2152607368 date "2014-08-01" @default.
- W2152607368 modified "2023-10-17" @default.
- W2152607368 title "Chemical speciation of iron in seawater using catalytic cathodic stripping voltammetry with ligand competition against salicylaldoxime" @default.
- W2152607368 cites W1592742956 @default.
- W2152607368 cites W1967070193 @default.
- W2152607368 cites W1968028266 @default.
- W2152607368 cites W1972837245 @default.
- W2152607368 cites W1973163746 @default.
- W2152607368 cites W1977201793 @default.
- W2152607368 cites W1980249464 @default.
- W2152607368 cites W1991887879 @default.
- W2152607368 cites W1995680662 @default.
- W2152607368 cites W1998259527 @default.
- W2152607368 cites W2000284822 @default.
- W2152607368 cites W2007393747 @default.
- W2152607368 cites W2008265007 @default.
- W2152607368 cites W2009592286 @default.
- W2152607368 cites W2014077506 @default.
- W2152607368 cites W2020704651 @default.
- W2152607368 cites W2021819616 @default.
- W2152607368 cites W2025700565 @default.
- W2152607368 cites W2029602975 @default.
- W2152607368 cites W2030212861 @default.
- W2152607368 cites W2031541902 @default.
- W2152607368 cites W2032260308 @default.
- W2152607368 cites W2046298462 @default.
- W2152607368 cites W2049475658 @default.
- W2152607368 cites W2051719218 @default.
- W2152607368 cites W2055898789 @default.
- W2152607368 cites W2058096761 @default.
- W2152607368 cites W2065563101 @default.
- W2152607368 cites W2066967714 @default.
- W2152607368 cites W2067352476 @default.
- W2152607368 cites W2068190050 @default.
- W2152607368 cites W2075306795 @default.
- W2152607368 cites W2076306005 @default.
- W2152607368 cites W2086449592 @default.
- W2152607368 cites W2092341931 @default.
- W2152607368 cites W2100445513 @default.
- W2152607368 cites W2108768986 @default.
- W2152607368 cites W2111087627 @default.
- W2152607368 cites W2127888210 @default.
- W2152607368 cites W2128432295 @default.
- W2152607368 cites W2141156900 @default.
- W2152607368 cites W2141208946 @default.
- W2152607368 cites W2147188726 @default.
- W2152607368 cites W2151276303 @default.
- W2152607368 cites W2151643323 @default.
- W2152607368 cites W2151842852 @default.
- W2152607368 cites W2157256930 @default.
- W2152607368 cites W2158643167 @default.
- W2152607368 cites W2162141932 @default.
- W2152607368 cites W2163803805 @default.
- W2152607368 cites W2170089944 @default.
- W2152607368 cites W2312314898 @default.
- W2152607368 cites W2318631117 @default.
- W2152607368 cites W2326052049 @default.
- W2152607368 cites W4249461298 @default.
- W2152607368 doi "https://doi.org/10.1016/j.marchem.2014.06.005" @default.
- W2152607368 hasPublicationYear "2014" @default.
- W2152607368 type Work @default.
- W2152607368 sameAs 2152607368 @default.
- W2152607368 citedByCount "80" @default.
- W2152607368 countsByYear W21526073682015 @default.
- W2152607368 countsByYear W21526073682016 @default.
- W2152607368 countsByYear W21526073682017 @default.
- W2152607368 countsByYear W21526073682018 @default.
- W2152607368 countsByYear W21526073682019 @default.
- W2152607368 countsByYear W21526073682020 @default.
- W2152607368 countsByYear W21526073682021 @default.
- W2152607368 countsByYear W21526073682022 @default.
- W2152607368 countsByYear W21526073682023 @default.
- W2152607368 crossrefType "journal-article" @default.
- W2152607368 hasAuthorship W2152607368A5023076826 @default.
- W2152607368 hasAuthorship W2152607368A5054242625 @default.
- W2152607368 hasConcept C107872376 @default.
- W2152607368 hasConcept C111368507 @default.
- W2152607368 hasConcept C116569031 @default.
- W2152607368 hasConcept C127313418 @default.
- W2152607368 hasConcept C147789679 @default.
- W2152607368 hasConcept C150394285 @default.
- W2152607368 hasConcept C161790260 @default.
- W2152607368 hasConcept C170493617 @default.
- W2152607368 hasConcept C17525397 @default.
- W2152607368 hasConcept C178790620 @default.
- W2152607368 hasConcept C179104552 @default.
- W2152607368 hasConcept C185592680 @default.
- W2152607368 hasConcept C18903297 @default.
- W2152607368 hasConcept C197248824 @default.
- W2152607368 hasConcept C2776838516 @default.
- W2152607368 hasConcept C2778741791 @default.
- W2152607368 hasConcept C2779603750 @default.
- W2152607368 hasConcept C52859227 @default.
- W2152607368 hasConcept C55493867 @default.