Redox Speciation of Vanadium in Estuarine Waters Using Improved Methodology Based on Anion Exchange Chromatography Coupled to HR ICP-MS System

Knežević, Lucija; Omanović, Dario; Bačić, Niko; Mandić, Jelena; Bura-Nakić, Elvira (2021) Redox Speciation of Vanadium in Estuarine Waters Using Improved Methodology Based on Anion Exchange Chromatography Coupled to HR ICP-MS System. Molecules, 26 (9). ISSN 1420-3049

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Abstract

An improved methodology was developed for V redox speciation in estuarine waters using a hyphenated technique consisting of ion chromatograph (IC) with an anion exchange column and a high-resolution inductively coupled plasma mass spectrometer (HR ICP-MS). This approach enables the direct determination of V(V), whereas reduced species (mainly V(IV)) are calculated by subtracting V(V) concentrations from the measured total V concentration. Based on the “on-column” V(V) chelation mechanism by EDTA, with the eluent composed of 40 mmol L−1 ammonium bicarbonate, 40 mmol L−1 ammonium sulphate, 8 mmol L−1 ethylenediaminetetraacetic acid and 3% acetonitrile, the method was successfully used for analyses of V redox speciation in samples taken in the vertical salinity gradient of the highly stratified Krka River estuary. Due to the matrix effects causing different sensitivities, a standard addition method was used for V(V) quantification purposes. The limit of detection (LOD) was also found to be matrix related: 101.68 ng L−1 in the seawater and 30.56 µg L−1 in the freshwater. Performed stability tests showed that V redox speciation is preserved at least 7 days in un-treated samples, possibly due to the stabilization of V-reduced species with natural organic matter (NOM). The dominant V form in the analysed samples was V(V) with the reduced V(IV) accounting for up to 26% of the total dissolved pool. The concentration of V(IV) was found to correlate negatively with the oxygen concentration. Significant removal of dissolved V was detected in oxygen depleted zones possibly related to the particle scavenging.

Item Type:	Article
Uncontrolled Keywords:	vanadium(V) redox speciation ; ion chromatography ; on-column complexation ; Krka River estuary ; high-salinity matrix
Subjects:	NATURAL SCIENCES > Chemistry
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Geokemija i zapis redoks indikatora u različitim uvjetima okoliša: prema boljem razumijevanju redoks uvjeta u prošlosti-REDOX Elvira Bura-Nakić IP-2018-01-7813 HRZZ Novi metodološki pristup biogeokemijskim istraživanjima specijacije metala u tragovima u obalnim vodenim ekosustavima-MEBTRACE Dario Omanović IP-2014-09-7530 HRZZ
Depositing User:	Dario Omanović
Date Deposited:	27 Apr 2021 07:44
URI:	http://fulir.irb.hr/id/eprint/6397
DOI:	10.3390/molecules26092436

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