Tandem Electrochemical Desalination-Potentiometric Nitrate Sensing for Seawater Analysis

M Cuartero; G A Crespo; Eric Bakker

doi:10.1021/acs.analchem.5b01973

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Tandem Electrochemical Desalination-Potentiometric Nitrate Sensing for Seawater Analysis

Journal article

Peer reviewed

Tandem Electrochemical Desalination-Potentiometric Nitrate Sensing for Seawater Analysis

M Cuartero, G A Crespo and Eric Bakker

Analytical Chemistry, Vol.87(16), pp.8084-8089

2015

DOI: https://doi.org/10.1021/acs.analchem.5b01973

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Abstract

Analytical Chemistry

Chemical Engineering

Other Chemical Sciences

carbon

desalination

electrodes

ion chromatography

ion exchange

ion exchange membranes

ion exchangers

ions

nitrates

potentiometers (electric measuring instruments)

yarn

We report on a methodology for the direct potentiometric determination of nitrate in seawater by in-line coupling to an electrochemical desalination module. A microfluidic custom-fabricated thin layer flat cell allows one to electrochemically reduce the chloride concentration of seawater more than 100-fold, from 600 mM down to ∼2.8 mM. The desalinator operates by the exhaustive electrochemical plating of the halides from the thin layer sample onto a silver element as silver chloride, which is coupled to the transfer of the counter cations across a permselective ion-exchange membrane to an outer solution. As a consequence of suppressing the major interference of an ion-exchanger based membrane, the 80 μL desalinated sample plug is passed to a potentiometric flow cell of 13 μL volume. The potentiometric sensor is composed of an all-solid-state nitrate selective electrode based on lipophilic carbon nanotubes (f-MWCNTs) as an ion-to-electron transducer (slope of -58.9 mV dec-1, limit of detection of 5 × 10-7 M, and response time of 5 s in batch mode) and a miniaturized reference electrode. Nitrate is successfully determined in desalinated seawater using ion chromatography as the reference method. It is anticipated that this concept may form an attractive platform for in situ environmental analysis of a variety of ions that normally suffer from interference by the high saline level of seawater. © 2015 American Chemical Society.

Details

Title: Tandem Electrochemical Desalination-Potentiometric Nitrate Sensing for Seawater Analysis
Authors: M Cuartero (Author) - University of Geneva, Switzerland
G A Crespo (Author) - University of Geneva, Switzerland
Eric Bakker (Author) - University of Geneva, Switzerland
Publication details: Analytical Chemistry, Vol.87(16), pp.8084-8089
Publisher: American Chemical Society
Date published: 2015
DOI: 10.1021/acs.analchem.5b01973
ISSN: 0003-2700
Organisation Unit: University of the Sunshine Coast, Queensland
Language: English
Record Identifier: 99449127602621
Output Type: Journal article

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