Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations

Jingying Zhai; Xiaojiang Xie; Eric Bakker

doi:10.1021/acs.analchem.5b03663

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Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations

Journal article

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Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations

Jingying Zhai, Xiaojiang Xie and Eric Bakker

Analytical Chemistry, Vol.87(24), p.12318–12323

2015

DOI: https://doi.org/10.1021/acs.analchem.5b03663

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Abstract

Analytical Chemistry

Chemical Engineering

Other Chemical Sciences

For half a century, complexometric titrations of metal ions have been performed with water-soluble chelators and indicators that typically require careful pH control. Very recently, ion-selective nanosphere emulsions were introduced that exhibit ion-exchange properties and are doped with lipophilic ionophores originally developed for chemical ion sensors. They may serve as novel, highly selective and pH independent complexometric reagents. While ion optode emulsions have been demonstrated as useful indicators for such titrations, they exhibit a pH crossresponse that unfortunately complicates the identification of the end point. Here, we present pH-independent optode nanospheres as indicators for complexometric titrations, with calcium as an initial example. The nanospheres incorporate an ionic solvatochromic dye (SD), ion exchanger and ionophore. The solvatochromic dye will be only expelled from the core of the nanosphere into the aqueous solution at the end point at which point it results in an optical signal change. The titration curves are demonstrated to be pH-independent and with sharper end points than with previously reported chromoionophore-based optical nanospheres as indicator. The calcium concentration in mineral water was successfully determined using this method.

Details

Title: Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations
Authors: Jingying Zhai (Author) - University of Geneva, Switzerland
Xiaojiang Xie (Author) - University of Geneva, Switzerland
Eric Bakker (Author) - University of Geneva, Switzerland
Publication details: Analytical Chemistry, Vol.87(24), p.12318–12323
Publisher: American Chemical Society
Date published: 2015
DOI: 10.1021/acs.analchem.5b03663
ISSN: 0003-2700
Organisation Unit: University of the Sunshine Coast, Queensland
Language: English
Record Identifier: 99449940302621
Output Type: Journal article

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