Arnaldo D'Amico

Tasting of beverages using an electronic tongue

An electronic tongue based on the sensor array of non-specific solution sensors together with pattern recognition tools has been applied to qualitative analysis of different beverages. It has been found that it is capable both to discriminate reliably between various sorts of the same type of beverages (tea, coffee, beer, soft drinks, juice, etc.) and to monitor the process of aging of juice. Correlations have been found between integral parameters produced by electronic tongue and quality of juice. Some conceptions and backgrounds used for electronic tongue development have been put forward and discussed.

A contribution on some basic definitions of sensors properties

HE continuous progress of the microelectronic technologies together with developments in material science has sustained the sensor area growth for many years. Contributing to sensor progress are advances in chemistry, biology, surface science, chaos and information theory, signal processing, nanotechnology, and simulation tools. All of these aspects, which are strongly pluridisciplinary in character, together with promising markets on the horizon in the fields of medicine, industrial processes, transportation, space, and food and beverage control, are contributing to the birth of the sensor science discipline. Moreover, the rather recent interests and efforts in many laboratories all over the world, in the DNA chip studies and genoma projects and in transgenic technologies, have enlarged even more the positive perspective of this rather young scientific domain. A positive consequence is its relevance and importance particularly in the development of social life in the near future. Some of the new branches of this revolution, for instance, bioinstrumentation, will certainly require more and more nanobiosensors which, although not yet completely identified, will certainly be promoters of new themes of advanced research and of needs of new fine technologies and nanometrology. In order to allow a coherent sensor development from both the scientific and technical point of view, it is necessary to promote an accurate dissemination of scientific information among all those interested in the sensor area. The knowledge of standards and that set of definitions, which have their roots into the branch of the measurement sci

Application of ’omics technologies to biomarker discovery in inflammatory lung diseases

Inflammatory lung diseases are highly complex in respect of pathogenesis and relationships between inflammation, clinical disease and response to treatment. Sophisticated large-scale analytical methods to quantify gene expression (transcriptomics), proteins (proteomics), lipids (lipidomics) and metabolites (metabolomics) in the lungs, blood and urine are now available to identify biomarkers that define disease in terms of combined clinical, physiological and patho-biological abnormalities. The aspiration is that these approaches will improve diagnosis, i.e. define pathological phenotypes, and facilitate the monitoring of disease and therapy, and also, unravel underlying molecular pathways. Biomarker studies can either select predefined biomarker(s) measured by specific methods or apply an “unbiased” approach involving detection platforms that are indiscriminate in focus. This article reviews the technologies presently available to study biomarkers of lung disease within the ’omics field. The contributions of the individual ’omics analytical platforms to the field of respiratory diseases are summarised, with the goal of providing background on their respective abilities to contribute to systems medicine-based studies of lung disease. Summary of the application of ’omics-based analytical platforms for biomarker discovery in inflammatory lung diseases http://ow.ly/mjGGc

An electronic nose for food analysis

Since the first developments of electronic noses, food analysis has been considered as one of its most useful applications. In this paper an electronic nose based on quartz microbalances coated with metallo-porphyrins and related compounds is presented and illustrated. Extensive tests on various substances playing key roles in food analysis show that sensing properties of the sensing materials (in terms of sensitivity and selectivity) can be exploited for electronic nose applications devoted to the analysis of various kinds of foods. The versatility of this system has been successfully tested on different kinds of foods, such as fish, meat, vegetable and wine for which results are shown.

Electronic nose and electronic tongue integration for improved classification of clinical and food samples

Abstract A combined approach based on a multisensor system, to get chemical information from liquid samples through the analysis of the solution and its head space is illustrated and commented. Sensors operating in liquid (electronic tongue) and in the head space (electronic nose) are based on the same sensitive materials: the metalloporphyrins. This gives the opportunity of a certain uniformity of interaction putting in evidence the differences between the solution and its related volatile part. The combined system has been tested in two different experiments in the fields of clinical and food analysis, respectively. Results have shown a net increase of information when the combined systems are used. The sensor fusion procedure has been optimised in order to achieve the best results.

Diagnostic Performance of an Electronic Nose, Fractional Exhaled Nitric Oxide, and Lung Function Testing in Asthma

BACKGROUND Analysis of exhaled breath by biosensors discriminates between patients with asthma and healthy subjects. An electronic nose consists of a chemical sensor array for the detection of volatile organic compounds (VOCs) and an algorithm for pattern recognition. We compared the diagnostic performance of a prototype of an electronic nose with lung function tests and fractional exhaled nitric oxide (FENO) in patients with atopic asthma. METHODS A cross-sectional study was undertaken in 27 patients with intermittent and persistent mild asthma and in 24 healthy subjects. Two procedures for collecting exhaled breath were followed to study the differences between total and alveolar air. Seven patients with asthma and seven healthy subjects participated in a study with mass spectrometry (MS) fingerprinting as an independent technique for assessing between group discrimination. Classification was based on principal component analysis and a feed-forward neural network. RESULTS The best results were obtained when the electronic nose analysis was performed on alveolar air. Diagnostic performance for electronic nose, FENO, and lung function testing was 87.5%, 79.2%, and 70.8%, respectively. The combination of electronic nose and FENO had the highest diagnostic performance for asthma (95.8%). MS fingerprints of VOCs could discriminate between patients with asthma and healthy subjects. CONCLUSIONS The electronic nose has a high diagnostic performance that can be increased when combined with FENO. Large studies are now required to definitively establish the diagnostic performance of the electronic nose. Whether this integrated noninvasive approach will translate into an early diagnosis of asthma has to be clarified. TRIAL REGISTRATION EUDRACT https://eudralink.emea.europa.eu; Identifier: 2007-000890-51; and clinicaltrials.gov; Identifier: NCT00819676.

Multicomponent analysis on polluted waters by means of an electronic tongue

In this paper the simultaneous measurements of the concentrations of a number of chemical species in solutions performed by a sensor array of ion sensitive electrodes are presented and discussed. By analogy with the well known electronic nose this sensor array operating in solutions, will be here called electronic tongue. In order to extract optimized information from the electronic tongue output data, many different techniques have been applied; they were based on chemometrics, non-linear least squares and neural networks. The best results have been achieved by the introduction of modular models which make use, at the same time, of both qualitative and quantitative information.

The application of metalloporphyrins as coating material for quartz microbalance-based chemical sensors

Abstract The results of both optimization and tests to prove the suitability of an array of quartz microbalance sensors (QMBs) modified with various metalloporphyrins for the determination of food freshness are presented and discussed. As far as optimization is concerned, it was found that a minimum amount of 50 μg of metalloporphyrin must be used for the modification of the quartz microbalance sensors in order to obtain the maximum sensitivity. The sensory behavior of five different porphyrins was subsequently studied. QMBs were modified using four different meso -tetraphenylporphyrins: phenyl, p -nitrophenyl, p -bromophenyl, p -methoxyphenyl and an octa-alkylporphyrin ( etio -porphyrin I), all loaded with a Co 2+ metal ion. A clear decrease in the sensitivity for the etio -porphyrin I was observed whereas for the meso -tetraphenyl-porphyrins the best response was obtained for the p -nitrophenyl derivative. These results can be attributed to the different electron densities which are present at the metal center of the macrocycle. The determination of the response behavior with respect to methanol, thiophene, diethylamine and triethylamine of a sensor array consisting of rhodium, ruthenium, cobalt, and manganese meso -tetraphenylporphyrin revealed that there is a clear difference in terms of the sensitivity and hence, the selectivity for the various QMBs. The rhodium and the cobalt-based QMBs were alike and demonstrated a preference for the gases with soft donating sites, i.e. thiophene and the amines. The QMBs based on ruthenium and manganese demonstrated distinctly different behavior. The ruthenium-based QMB demonstrated no clear preference for gases with either hard or soft donating sites, whereas the manganese-based QMB preferred gases with hard donating sites, i.e. methanol. These results led to the overall conclusion that this sensor array could be used for the analysis of complex gas mixtures, where the most prevalent gases fall under the categories of the amines, the alcohols and the sulphides.

Electronic tongue: new analytical tool for liquid analysis on the basis of non-specific sensors and methods of pattern recognition

Abstract Development of promising sensor instrument — “electronic tongue” based on sensor arrays with data processing by pattern recognition methods have been described. The attention is paid to “electronic tongue” based on an array of original non-specific (non-selective) potentiometric chemical sensors with chalcogenide glass membranes. Principles of research, criteria for the development of non-selective sensing materials, pattern recognition methods have been described. Possible applications and some results of integral qualitative analysis of beverages and of quantitative analysis of complex liquids, containing heavy metals are reported. Discriminating power obtained and possibility of multicomponent analysis permit to consider “electronic tongue” as a perspective analytical concept.

An electronic nose for the recognition of the vineyard of a red wine

Sensor arrays have been tentatively utilized in the past as tools for the odours characterisation of particular classes of foods and beverages. In this paper a technique aiming to discriminate among similar wines is described. A sensor array of metal-oxide based gas sensors was employed for the recognition of two wines, having the same denomination (Groppello red wine) but coming from different vineyards. The performance of the array was compared with that of the standard chemical analytical approach adopted by the wines authority.