Solid-Contact Potentiometric Sensors and Multisensors Based on Polyaniline and Thiacalixarene Receptors for the Analysis of Some Beverages and Alcoholic Drinks

Abstract

Electronic tongue is a sensor array that aims to discriminate and analyze complex media like food and beverages on the base of chemometrics approaches for data mining and pattern recognition. In this review, the concept of electronic tongue comprising of solid-contact potentiometric sensors with polyaniline and thacalix[4]arene derivatives is described. The electrochemical reactions of polyaniline as a background of solid-contact sensors and the characteristics of thiacalixarenes and pillararenes as neutral ionophores are briefly considered. The electronic tongue systems described were successfully applied for assessment of fruit juices, green tea, beer, and alcoholic drinks They were classified in accordance with the origination, brands and styles. Variation of the sensor response resulted from the reactions between Fe(III) ions added and sample components, i.e., antioxidants and complexing agents. The use of principal component analysis and discriminant analysis is shown for multisensor signal treatment and visualization. The discrimination conditions can be optimized by variation of the ionophores, Fe(III) concentration, and sample dilution. The results obtained were compared with other electronic tongue systems reported for the same subjects.

Optimization of Sensors to be Used in a Voltammetric Electronic Tongue Based on Clustering Metrics

“…For the selection of the optimal sensor array, data was submitted to PCA and CVA, and the clustering observed was evaluated by means of the F factor [ 29 , 30 , 31 ]. The F factor is defined as the ratio of variances between different clusters and the sum of internal variance in all clusters (Equation (1)).…”

Prospects of Membrane Science Development

“…To increase the adhesion of the sensitive layer of solid-contact sensors, polymers obtained via the electropolymerization directly on the electrode surface, into which active components can be introduced later, are used. Polyaniline [86], polypyrrole [87,88], and polythiophenes [88] with electron-ion conductivity, the morphology and properties of which are varied by means of controlling the electrochemical parameters of the synthesis, appear to be the most promising for these purposes.…”

Hybrid Materials Based on MF-4SC Membranes and Carbon Nanotubes: Transport Properties and Characteristics of DP-sensors in Hydrophobic Amino Acid Solutions

“…The membranes were stored in deionized water; immediately before measurements, the samples were withdrawn and wiped with filter paper. Water uptake ( was calculated by the formula (3) where Δm is the difference in the weight of the samples before the heat treatment and after holding at 200°C (g) and m is the weight of the sample before the heat treatment (g).…”

“…A promising application of the membrane science is the synthesis of sensor systems based on modified ion-exchange materials, particularly, hybrid membranes [1]. In potentiometric sensors, these materials solve the problem of low adhesion of the sensitive layer to the electrode surface and act as ion-electron converters [2,3]; in voltammetric sensors, these materials decrease the overpotential of the electrode reaction and increase the selectivity and electrocatalytic activity with respect to the analyte [4,5]. In addition, hybrid materials can increase the analyte sorption on the electrode or hinder the sorption of compounds that poison the electrode material.…”

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