Luis Gil-Sánchez

An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions

An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni) encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH4)2SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate.

Antioxidant activity and physicochemical parameters for the differentiation of honey using a potentiometric electronic tongue

BACKGROUND This work evaluates the capacity of a potentiometric electronic tongue to differentiate between types of honey (orange blossom, rosemary, thyme, sunflower, winter savory and honeydew honey) according to their antioxidant level. The classical procedures used to evaluate the antioxidant potential of honey are inappropriate for in situ monitoring on reception of batches of raw honey in the packaging industry. They are also destructive, time-consuming and very tedious, requiring highly expert analysts and specialised equipment. RESULTS The electronic tongue system made with Ag, Ni, Co, Cu and Au was able to not only differentiate between types of honey but also to predict their total antioxidant capacity. The discrimination ability of the system was proved by means of a fuzzy ARTMAP type ANN, with 100% classification success. A prediction multiple linear regression model showed that the best correlation coefficient was for antioxidant activity (0.9666), then for electrical conductivity (0.8959) and to a lesser extent for aw , moisture and colour. CONCLUSION The proposed measurement system could be a quick, easy option for the honey packaging sector to provide continuous in-line information about a characteristic as important as the antioxidant level.

Classification of honeys of different floral origins by artificial neural networks

In this study, the data obtained from a potentiometric electronic tongue system are analyzed using a Fuzzy-Artmap artificial neural network. The analysis is focused on determining the optimal configuration of the neural network in order to achieve the proper classification of the honey analysed, as well as to adjust its size for further implementation in a microcontroller system. The application submitted has been employed to discriminate several varieties of honey according to the types of floral origin (citrus, rosemary, polyfloral and honeydew) and considering three different physical treatment: raw, liquefied and pasteurized. The measures have been carried out using a set of metal electrodes of different materials. We have used eight electrodes of various metals (pure and chemically treated). In order to implement the neural networks, a Graphic User Interface (GUI) in Matlab has been developed, fixing thereby the parameters of neural networks and obtaining the classification of the samples. Moreover, the information needed to implement neural networks in microcontroller systems is also generated to ensure an autonomous system of electronic tongue applied to the analysis of honey‥

Teaching Electronics to Aeronautical Engineering Students by Developing Projects

Teaching electronics to an aerospace engineer with a very limited number of credits has been a major challenge for us. This goal has been achieved through a teaching method based on real projects that are closely related to aerospace engineering. Throughout this paper, the process of teaching electronics through two subjects, one compulsory and one elective, is described. Subsequently, a description of the major projects that have been implemented in the last years is given. The academic results have been very satisfactory, and project development has proved a widely accepted method of teaching by students.

Embedded pattern recognition systems for liquids classification: A comparison study

A comparative study among a Fuzzy ARTMAP, a Multi-Layer Feed-Forward network (MLFF) and a Linear Discriminant Analysis (LDA) has been done in a liquids classification system in order to obtain the best implementation on a microcontroller based system. These algorithms are initially trained with a multi-electrode array on a Personal Computer (PC) using several samples of waters to obtain the optimum architecture of the networks. Once it is trained, the computed data are programmed into the microcontroller, which then gives the water classification directly for new unknown water samples. The multi-electrode has been developed using thick-film technology

Meat and Fish Spoilage Measured by Electronic Tongues

Monitoring of meat and fish spoilage by electronic tongues (e-tongue) is a particular application that has been developed at a later stage in comparison with the analysis of other types of foods of liquids. The reason for this delay has been the difficulty of finding measuring methods able to achieve a good contact between the electrodes of the tongue and the samples in order to obtain a good reproducibility of the results. In this chapter we report an overview of work devoted to the use of potentiometric, voltammetric, or impedance spectroscopy electronic tongues in the monitorization of fish or meat spoilage.

Electronic sensors subject for students from degrees of chemistry and environment

This presentation describes the teaching experience in a course on Sensors Electronics following the criteria of the Erasmus Mundus Masters and applied to International Master in Materials and Sensor Systems for Environmental Technologies given at Universitat Politècnica de Valencia. The main teaching challenge was to provide a course of clearly electronic content to students from any related field, mostly with chemistry and the environment, for this, a program with a large practical component was developed and therefore, electronic modules for measurements with different types of sensors were constructed and applied.