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

Zhai, Jingying; Xie, Xiaojiang; Bakker, Eric

doi:10.1021/acs.analchem.5b03663

Scientific article

English

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

Contributors

Zhai, Jingying; Xie, Xiaojiang; Bakker, Eric

Published in

Analytical Chemistry, vol. 87, no. 24, p. 12318-12323

Publication date

2015

Abstract

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.

UNIGE affiliation entities

Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

UNIGE research groups

Groupe Bakker

Citation (ISO format)

ZHAI, Jingying, XIE, Xiaojiang, BAKKER, Eric. Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations. In: Analytical Chemistry, 2015, vol. 87, n° 24, p. 12318–12323. doi: 10.1021/acs.analchem.5b03663

Article (Published version)

Identifiers

PID : unige:97899
DOI : 10.1021/acs.analchem.5b03663

Journal ISSN

0003-2700

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

Contributors

Published in

Publication date

Abstract

UNIGE affiliation entities

UNIGE research groups

Citation (ISO format)

Main files (1)

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Journal ISSN

Technical informations

Creation

First validation

Update

Status update

Last indexation