- a A.M. Butlerov’ Chemistry Institute, Kazan State University, 18 Kremlevskaya Street, Kazan 420008, Russian Federation
- b Department of the Modeling of Ecological Systems of Kazan State University, 18 Kremlevskaya Street, Kazan 42008, Russian Federation
- Received 29 January 2010, Revised 19 April 2010, Accepted 10 May 2010, Available online 19 May 2010
Abstract
Solid-contact
ion-selective electrodes based on glassy carbon electrode covered with
electropolymerized polyaniline and tetrasubstituted thiacalix[4]arene
ionophores with hexyl and o-pyridylamido functional groups at
the lower rim have been developed and examined in the discrimination of
the brands of apple juices and herbal liqueurs. For this purpose, the
liquids tested were diluted and spiked with a constant amount of Fe3+ ions. The variation of the signal toward Fe3+
ions was achieved due to their involvement in the reactions with the
organic ligands and the antioxidants present. As was shown, the
combination of the three electrodes with various receptors makes it
possible to predict the brand of apple juices and herbal liqueurs using
linear discriminant analysis in 95–100% cases. The discrimination
procedure makes it possible to discriminate liquids within 20 min.
Besides, the electrodes developed make it possible to detect individual
antioxidants (ascorbic, malic, oxalic acids, hydroquinone, and
quercetin) in the range from 5.0 × 10−6 to 1.0 × 10−2 M in direct potentiometric measurements and redox titration.
Keywords
- Solid-contact ion-selective electrode;
- Thiacalixarene;
- Principal component analysis;
- Linear discriminant analysis
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