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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Tracer-monitored flow titrations

Full text
Author(s):
Sasaki, Milton K. [1] ; Rocha, Diogo L. [1] ; Rocha, Fabio R. P. [1] ; Zagatto, Elias A. G. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13400970 Piracicaba - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Analytica Chimica Acta; v. 902, p. 123-128, JAN 1 2016.
Web of Science Citations: 4
Abstract

The feasibility of implementing tracer-monitored titrations in a flow system is demonstrated. A dye tracer is used to estimate the instant sample and titrant volumetric fractions without the need for volume, mass or peak width measurements. The approach was applied to spectrophotometric flow titrations involving variations of sample and titrant flow-rates (i.e. triangle programmed technique) or concentration gradients established along the sample zone (i.e. flow injection system). Both strategies required simultaneous monitoring of two absorbing species, namely the titration indicator and the dye tracer. Mixing conditions were improved by placing a chamber with mechanical stirring in the analytical path aiming at to minimize diffusional effects. Unlike most of flow based titrations, the innovation is considered as a true titration, as it does not require a calibration curve thus complying with IUPAC definition. As an application, acidity evaluation in vinegars involving titration with sodium hydroxide was selected. Phenolphthalein and brilliant blue ELF were used as indicator and dye tracer, respectively. Effects of sample volume, titrandititrant concentrations and flow rates were investigated aiming at improved accuracy and precision. Results were reliable and in agreement with those obtained by a reference titration procedure. (C) 2015 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 11/14413-0 - Comparison of flow analyzers with laminar or pulsed flows and immobilized reagents: application to samples of pharmaceutical, agronomical and/or environmental relevance
Grantee:Milton Katsumi Sasaki
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 11/23498-9 - Advanced flow systems for technological, agronomical and environmental analysis
Grantee:Elias Ayres Guidetti Zagatto
Support Opportunities: Research Projects - Thematic Grants