Simultaneous determination of soluble manganese(III), manganese(II) and total manganese in natural (pore)waters

Andrew S Madison; Bradley M Tebo; George W Luther 3rd

doi:10.1016/j.talanta.2011.01.025

Simultaneous determination of soluble manganese(III), manganese(II) and total manganese in natural (pore)waters

Talanta. 2011 Apr 15;84(2):374-81. doi: 10.1016/j.talanta.2011.01.025. Epub 2011 Jan 19.

Authors

Andrew S Madison¹, Bradley M Tebo, George W Luther 3rd

Affiliation

¹ School of Marine Science and Policy, College of Earth, Ocean and Environment, University of Delaware, Lewes, DE 19958, USA. amadison@udel.edu

PMID: 21376960
DOI: 10.1016/j.talanta.2011.01.025

Abstract

A new spectrophotometric protocol was developed for the simultaneous determination of soluble Mn(III), Mn(II) and total Mn [sum of soluble Mn(III) and Mn(II)] in sediment porewaters using a water soluble meso-substituted porphyrin [α,β,γ,δ-tetrakis(4-carboxyphenyl)porphine (T(4-CP)P)]. A simple kinetic rate model is used to quantify soluble Mn(II), Mn(III) and total Mn concentrations during a metal substitution reaction. Under optimized conditions, the method accurately determines soluble Mn(II) and Mn(III) within a concentration range of 100 nM-10 μM. The detection limit of total soluble Mn is 50 nM. Using this method, soluble Mn(II) and Mn(III) concentrations were determined in standard solutions within 0.4-2% of the known values and agreed closely with results of inductively coupled plasma mass spectrometric and voltammetric analyses. The procedure was successfully applied to determine soluble Mn(II), Mn(III) and total Mn in sediment porewaters of the Lower St. Lawrence Estuary. Mn(III) represented up to 85% of the total soluble Mn pool in surface sediments.