Concentrations of reactive Mn(III)-L and MnO 2 in estuarine and marine waters determined using spectrophotometry and the leuco base, leucoberbelin blue

Matthew R. Jones, George W. Luther, Alfonso Mucci, Bradley Tebo

Research output: Contribution to journalArticle

Abstract

In terms of its oxidative strength, the MnO 2 /Mn 2+ couple is one of the strongest in the aquatic environment. The intermediate oxidation state, manganese(III), is stabilized by a range of organic ligands (Mn(III)-L) and some of these complexes are also strong oxidants or reductants. Here, we present improved methods for quantifying soluble reactive oxidized manganese(III) and particulate reactive oxidized manganese at ultra-low concentrations; the respective detection limits are 6.7 nM and 7 pM (100-cm spectrophotometric path length) and 260 nM and 2.6 nM (1-cm path length). The methods involve a simple, specific, spectrophotometric technique using a water-soluble leuco base (leucoberbelin blue; LBB). LBB is oxidized by manganese through a hydrogen atom transfer reaction forming a colored complex that is stoichiometrically related to the oxidation state of the manganese, either Mn(III)-L or manganese(III,IV) oxides (MnO x ). At the concentration of LBB used in this study, nitrite may be a minor interference, so we provide concentration ranges over which it interferes and suggest potential strategies to mitigate the interference. Unlike previous methods devised to quantify Mn(III)-L, which use ligand exchange reactions, the LBB oxidation requires an electron and therefore needs to physically contact manganese(III) for inner-sphere electron transfer to occur. The method for measuring soluble Mn(III)-L was evaluated in the laboratory, and LBB was found to be oxidized by an extensive suite of weak Mn(III)-L complexes, as it is by MnO x , but could not react with or reacted very slowly with strong Mn(III)-L complexes. According to the molecular structures of the Mn(III)-L complexes tested, LBB can also be used to qualitatively assess the binding strength of Mn(III)-L complexes based on metal-chelate structural considerations. The assays for soluble Mn(III)-L (membrane filtered) and particulate manganese oxides (trapped by membrane filters) were applied to the well-oxygenated estuarine waters of the Saguenay Fjord, a major tributary of the Lower St. Lawrence Estuary, and to Western North Atlantic oceanic waters, off the continental shelf, where there is an oxygen minimum zone (< 67% O 2 saturation). The methods applied can be used in the field or onboard ships and provide important new insights into oxidized manganese speciation.

Original languageEnglish (US)
Pages (from-to)91-99
Number of pages9
JournalTalanta
Volume200
DOIs
StatePublished - Aug 1 2019

Fingerprint

Spectrophotometry
Manganese
Water
Estuaries
Oxidation
Oxides
Structural metals
Electrons
Ligands
Membranes
Ships
Reducing Agents
Nitrites
Molecular Structure
Oxidants
Molecular structure
Limit of Detection
Hydrogen
Assays
Ion exchange

Keywords

  • Leucoberbelin Blue (LBB)
  • Manganese speciation
  • Mn(III)-L
  • MnO
  • Seawater
  • Spectrophotometry

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry(all)
  • Biochemistry
  • Spectroscopy

Cite this

Concentrations of reactive Mn(III)-L and MnO 2 in estuarine and marine waters determined using spectrophotometry and the leuco base, leucoberbelin blue . / Jones, Matthew R.; Luther, George W.; Mucci, Alfonso; Tebo, Bradley.

In: Talanta, Vol. 200, 01.08.2019, p. 91-99.

Research output: Contribution to journalArticle

@article{8dcd4bac20164526a48069fe83df5aa4,
title = "Concentrations of reactive Mn(III)-L and MnO 2 in estuarine and marine waters determined using spectrophotometry and the leuco base, leucoberbelin blue",
abstract = "In terms of its oxidative strength, the MnO 2 /Mn 2+ couple is one of the strongest in the aquatic environment. The intermediate oxidation state, manganese(III), is stabilized by a range of organic ligands (Mn(III)-L) and some of these complexes are also strong oxidants or reductants. Here, we present improved methods for quantifying soluble reactive oxidized manganese(III) and particulate reactive oxidized manganese at ultra-low concentrations; the respective detection limits are 6.7 nM and 7 pM (100-cm spectrophotometric path length) and 260 nM and 2.6 nM (1-cm path length). The methods involve a simple, specific, spectrophotometric technique using a water-soluble leuco base (leucoberbelin blue; LBB). LBB is oxidized by manganese through a hydrogen atom transfer reaction forming a colored complex that is stoichiometrically related to the oxidation state of the manganese, either Mn(III)-L or manganese(III,IV) oxides (MnO x ). At the concentration of LBB used in this study, nitrite may be a minor interference, so we provide concentration ranges over which it interferes and suggest potential strategies to mitigate the interference. Unlike previous methods devised to quantify Mn(III)-L, which use ligand exchange reactions, the LBB oxidation requires an electron and therefore needs to physically contact manganese(III) for inner-sphere electron transfer to occur. The method for measuring soluble Mn(III)-L was evaluated in the laboratory, and LBB was found to be oxidized by an extensive suite of weak Mn(III)-L complexes, as it is by MnO x , but could not react with or reacted very slowly with strong Mn(III)-L complexes. According to the molecular structures of the Mn(III)-L complexes tested, LBB can also be used to qualitatively assess the binding strength of Mn(III)-L complexes based on metal-chelate structural considerations. The assays for soluble Mn(III)-L (membrane filtered) and particulate manganese oxides (trapped by membrane filters) were applied to the well-oxygenated estuarine waters of the Saguenay Fjord, a major tributary of the Lower St. Lawrence Estuary, and to Western North Atlantic oceanic waters, off the continental shelf, where there is an oxygen minimum zone (< 67{\%} O 2 saturation). The methods applied can be used in the field or onboard ships and provide important new insights into oxidized manganese speciation.",
keywords = "Leucoberbelin Blue (LBB), Manganese speciation, Mn(III)-L, MnO, Seawater, Spectrophotometry",
author = "Jones, {Matthew R.} and Luther, {George W.} and Alfonso Mucci and Bradley Tebo",
year = "2019",
month = "8",
day = "1",
doi = "10.1016/j.talanta.2019.03.026",
language = "English (US)",
volume = "200",
pages = "91--99",
journal = "Talanta",
issn = "0039-9140",
publisher = "Elsevier",

}

TY - JOUR

T1 - Concentrations of reactive Mn(III)-L and MnO 2 in estuarine and marine waters determined using spectrophotometry and the leuco base, leucoberbelin blue

AU - Jones, Matthew R.

AU - Luther, George W.

AU - Mucci, Alfonso

AU - Tebo, Bradley

PY - 2019/8/1

Y1 - 2019/8/1

N2 - In terms of its oxidative strength, the MnO 2 /Mn 2+ couple is one of the strongest in the aquatic environment. The intermediate oxidation state, manganese(III), is stabilized by a range of organic ligands (Mn(III)-L) and some of these complexes are also strong oxidants or reductants. Here, we present improved methods for quantifying soluble reactive oxidized manganese(III) and particulate reactive oxidized manganese at ultra-low concentrations; the respective detection limits are 6.7 nM and 7 pM (100-cm spectrophotometric path length) and 260 nM and 2.6 nM (1-cm path length). The methods involve a simple, specific, spectrophotometric technique using a water-soluble leuco base (leucoberbelin blue; LBB). LBB is oxidized by manganese through a hydrogen atom transfer reaction forming a colored complex that is stoichiometrically related to the oxidation state of the manganese, either Mn(III)-L or manganese(III,IV) oxides (MnO x ). At the concentration of LBB used in this study, nitrite may be a minor interference, so we provide concentration ranges over which it interferes and suggest potential strategies to mitigate the interference. Unlike previous methods devised to quantify Mn(III)-L, which use ligand exchange reactions, the LBB oxidation requires an electron and therefore needs to physically contact manganese(III) for inner-sphere electron transfer to occur. The method for measuring soluble Mn(III)-L was evaluated in the laboratory, and LBB was found to be oxidized by an extensive suite of weak Mn(III)-L complexes, as it is by MnO x , but could not react with or reacted very slowly with strong Mn(III)-L complexes. According to the molecular structures of the Mn(III)-L complexes tested, LBB can also be used to qualitatively assess the binding strength of Mn(III)-L complexes based on metal-chelate structural considerations. The assays for soluble Mn(III)-L (membrane filtered) and particulate manganese oxides (trapped by membrane filters) were applied to the well-oxygenated estuarine waters of the Saguenay Fjord, a major tributary of the Lower St. Lawrence Estuary, and to Western North Atlantic oceanic waters, off the continental shelf, where there is an oxygen minimum zone (< 67% O 2 saturation). The methods applied can be used in the field or onboard ships and provide important new insights into oxidized manganese speciation.

AB - In terms of its oxidative strength, the MnO 2 /Mn 2+ couple is one of the strongest in the aquatic environment. The intermediate oxidation state, manganese(III), is stabilized by a range of organic ligands (Mn(III)-L) and some of these complexes are also strong oxidants or reductants. Here, we present improved methods for quantifying soluble reactive oxidized manganese(III) and particulate reactive oxidized manganese at ultra-low concentrations; the respective detection limits are 6.7 nM and 7 pM (100-cm spectrophotometric path length) and 260 nM and 2.6 nM (1-cm path length). The methods involve a simple, specific, spectrophotometric technique using a water-soluble leuco base (leucoberbelin blue; LBB). LBB is oxidized by manganese through a hydrogen atom transfer reaction forming a colored complex that is stoichiometrically related to the oxidation state of the manganese, either Mn(III)-L or manganese(III,IV) oxides (MnO x ). At the concentration of LBB used in this study, nitrite may be a minor interference, so we provide concentration ranges over which it interferes and suggest potential strategies to mitigate the interference. Unlike previous methods devised to quantify Mn(III)-L, which use ligand exchange reactions, the LBB oxidation requires an electron and therefore needs to physically contact manganese(III) for inner-sphere electron transfer to occur. The method for measuring soluble Mn(III)-L was evaluated in the laboratory, and LBB was found to be oxidized by an extensive suite of weak Mn(III)-L complexes, as it is by MnO x , but could not react with or reacted very slowly with strong Mn(III)-L complexes. According to the molecular structures of the Mn(III)-L complexes tested, LBB can also be used to qualitatively assess the binding strength of Mn(III)-L complexes based on metal-chelate structural considerations. The assays for soluble Mn(III)-L (membrane filtered) and particulate manganese oxides (trapped by membrane filters) were applied to the well-oxygenated estuarine waters of the Saguenay Fjord, a major tributary of the Lower St. Lawrence Estuary, and to Western North Atlantic oceanic waters, off the continental shelf, where there is an oxygen minimum zone (< 67% O 2 saturation). The methods applied can be used in the field or onboard ships and provide important new insights into oxidized manganese speciation.

KW - Leucoberbelin Blue (LBB)

KW - Manganese speciation

KW - Mn(III)-L

KW - MnO

KW - Seawater

KW - Spectrophotometry

UR - http://www.scopus.com/inward/record.url?scp=85062804448&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85062804448&partnerID=8YFLogxK

U2 - 10.1016/j.talanta.2019.03.026

DO - 10.1016/j.talanta.2019.03.026

M3 - Article

VL - 200

SP - 91

EP - 99

JO - Talanta

JF - Talanta

SN - 0039-9140

ER -