Understanding Le Châtelier's principle fundamentals: five key questions

[EN] The well-known Le Châtelier's principle is almost always mentioned when dealing with chemical equilibrium. Nevertheless, although a must in most general chemistry courses starting from the secondary level, when students face questions about it, some major misconceptions are often highlighted; to avoid this, a somewhat challenging problem is now presented. It can be deemed a very useful tool for a full understanding of this principle and chemical equilibrium as a whole. A generic chemical reaction at equilibrium is subject to different types of perturbation, and the student is required ¿ in each case ¿ to identify the new position of equilibrium among a number of proposals. The correct answers are finally provided along with the corresponding explanations.Peris Tortajada, M. (2021). Understanding Le Châtelier's principle fundamentals: five key questions. Chemistry Teacher International. 1-3. https://doi.org/10.1515/cti-2020-0030S13Chang, R., & Goldsby, K. (2015). Chemistry (12th ed.). New York, U.S.A.: McGraw-Hill Education.Cheung, D. (2009). The adverse effects of Le Châtelier’s principle on teacher understanding of chemical equilibrium. Journal of Chemical Education, 86, 514. https://doi.org/10.1021/ed086p514.Hackling, M. W., & Garnett, P. J. (1985). Misconceptions of chemical equilibrium. European Journal of Science Education, 7, 205–214. https://doi.org/10.1080/0140528850070211.Novak, I. (2018). Geometrical description of chemical equilibrium and Le Châtelier’s principle: two-component systems. Journal of Chemical Education, 95, 84–87. https://doi.org/10.1021/acs.jchemed.7b00665.Petrucci, R. H., & Herring, F. G. (2016). General chemistry: principles and modern applications (11th ed.). London, U.K.: Pearson PLC.Satriana, T., Yamtinah, S., Ashadi, A., & Indriyanti, N.Y. (2018). Student’s profile of misconception in chemical equilibrium. In IOP Conf. Series: Journal of Physics: Conf. Series (1097, pp. 012066–012073). Bristol, U.K.: IOP Publishing Ltd, 012066

Electronic noses and tongues to assess food authenticity and adulteration

[EN] Background: There is a growing concern for the problem of food authenticity assessment (and hence the detection of food adulteration), since it cheats the consumer and can pose serious risk to health in some instances. Unfortunately, food safety/integrity incidents occur with worrying regularity, and therefore there is clearly a need for the development of new analytical techniques. Scope and approach: In this review, after briefly commenting the principles behind the design of electronic noses and electronic tongues, the most relevant contributions of these sensor systems in food adulteration control and authenticity assessment over the past ten years are discussed. It is also remarked that future developments in the utilization of advanced sensors arrays will lead to superior electronic senses with more capabilities, thus making the authenticity and falsification assessment of food products a faster and more reliable process. Key findings and conclusions: The use of both types of e-devices in this field has been steadily increasing along the present century, mainly due to the fact that their efficiency has been significantly improved as important developments are taking place in the area of data handling and multivariate data analysis methods. (C) 2016 Elsevier Ltd. All rights reserved.Peris Tortajada, M.; Escuder Gilabert, L. (2016). Electronic noses and tongues to assess food authenticity and adulteration. Trends in Food Science and Technology. 58:40-54. doi:10.106/j.tifs.2016.10.014S40545

IoT Technologies in Chemical Analysis Systems: Application to Potassium Monitoring in Water.

[EN] The in-line determination of chemical parameters in water is of capital importance for environmental reasons. It must be carried out frequently and at a multitude of points; thus, the ideal method is to utilize automated monitoring systems, which use sensors based on many transducers, such as Ion Selective Electrodes (ISE). These devices have multiple advantages, but their management via traditional methods (i.e., manual sampling and measurements) is rather complex. Wireless Sensor Networks have been used in these environments, but there is no standard way to take advantage of the benefits of new Internet of Things (IoT) environments. To deal with this, an IoT-based generic architecture for chemical parameter monitoring systems is proposed and applied to the development of an intelligent potassium sensing system, and this is described in detail in this paper. This sensing system provides fast and simple deployment, interference rejection, increased reliability, and easy application development. Therefore, in this paper, we propose a method that takes advantage of Cloud services by applying them to the development of a potassium smart sensing system, which is integrated into an IoT environment for use in water monitoring applications. The results obtained are in good agreement (correlation coefficient = 0.9942) with those of reference methods.FundingThis research was funded by Spanish Ministerio de Economia y Competitividad, Gobierno de Espana, grant number DPI2016-80303-C2-1-P.Campelo Rivadulla, JC.; Capella Hernández, JV.; Ors Carot, R.; Peris Tortajada, M.; Bonastre Pina, AM. (2022). IoT Technologies in Chemical Analysis Systems: Application to Potassium Monitoring in Water. Sensors. 22(3):1-16. https://doi.org/10.3390/s2203084211622

A New Ammonium Smart Sensor with Interference Rejection

[EN] In many water samples, it is important to determine the ammonium concentration in order to obtain an overall picture of the environmental impact of pollutants and human actions, as well as to detect the stage of eutrophization. Ion selective electrodes (ISEs) have been commonly utilized for this purpose, although the presence of interfering ions (potassium and sodium in the case of NH4+-ISE) represents a handicap in terms of the measurement quality. Furthermore, random malfunctions may give rise to incorrect measurements. Bearing all of that in mind, a smart ammonium sensor with enhanced features has been developed and tested in water samples, as demonstrated and commented on in detail following the presentation of the complete set of experimental measurements that have been successfully carried out. This has been achieved through the implementation of an expert system that supervises a set of ISEs in order to (a) avoid random failures and (b) reject interferences. Our approach may also be suitable for in-line monitoring of the water quality through the implementation of wireless sensor networks.This research was supported by the Spanish Ministerio de Economia y Competitividad, grant number DPI2016-80303-C2-1-P.Capella Hernández, JV.; Bonastre Pina, AM.; Campelo Rivadulla, JC.; Ors Carot, R.; Peris Tortajada, M. (2020). A New Ammonium Smart Sensor with Interference Rejection. Sensors. 20(24):1-17. https://doi.org/10.3390/s20247102S1172024Molins-Legua, C., Meseguer-Lloret, S., Moliner-Martinez, Y., & Campíns-Falcó, P. (2006). A guide for selecting the most appropriate method for ammonium determination in water analysis. TrAC Trends in Analytical Chemistry, 25(3), 282-290. doi:10.1016/j.trac.2005.12.002Zhu, Y., Chen, J., Yuan, D., Yang, Z., Shi, X., Li, H., … Ran, L. (2019). Development of analytical methods for ammonium determination in seawater over the last two decades. TrAC Trends in Analytical Chemistry, 119, 115627. doi:10.1016/j.trac.2019.115627Liu, J. (2020). New directions in sensor technology. TrAC Trends in Analytical Chemistry, 124, 115818. doi:10.1016/j.trac.2020.115818Yaroshenko, I., Kirsanov, D., Marjanovic, M., Lieberzeit, P. A., Korostynska, O., Mason, A., … Legin, A. (2020). Real-Time Water Quality Monitoring with Chemical Sensors. Sensors, 20(12), 3432. doi:10.3390/s20123432Martı́nez-Máñez, R., Soto, J., Garcia-Breijo, E., Gil, L., Ibáñez, J., & Llobet, E. (2005). An «electronic tongue» design for the qualitative analysis of natural waters. Sensors and Actuators B: Chemical, 104(2), 302-307. doi:10.1016/j.snb.2004.05.022Legin, A. ., Rudnitskaya, A. ., Vlasov, Y. ., Di Natale, C., & D’Amico, A. (1999). The features of the electronic tongue in comparison with the characteristics of the discrete ion-selective sensors. Sensors and Actuators B: Chemical, 58(1-3), 464-468. doi:10.1016/s0925-4005(99)00127-6Mueller, A. V., & Hemond, H. F. (2013). Extended artificial neural networks: Incorporation of a priori chemical knowledge enables use of ion selective electrodes for in-situ measurement of ions at environmentally relevant levels. Talanta, 117, 112-118. doi:10.1016/j.talanta.2013.08.045Wen, Y., Mao, Y., Kang, Z., & Luo, Q. (2019). Application of an ammonium ion-selective electrode for the real-time measurement of ammonia nitrogen based on pH and temperature compensation. Measurement, 137, 98-101. doi:10.1016/j.measurement.2019.01.031Handbook of Electrochemistry. (2007). doi:10.1016/b978-0-444-51958-0.x5000-9Umezawa, Y., Bühlmann, P., Umezawa, K., Tohda, K., & Amemiya, S. (2000). Potentiometric Selectivity Coefficients of Ion-Selective Electrodes. Part I. Inorganic Cations (Technical Report). Pure and Applied Chemistry, 72(10), 1851-2082. doi:10.1351/pac200072101851Capella, J. V., Bonastre, A., Ors, R., & Peris, M. (2015). An interference-tolerant nitrate smart sensor for Wireless Sensor Network applications. Sensors and Actuators B: Chemical, 213, 534-540. doi:10.1016/j.snb.2015.02.125Choudhary, J., Balasubramanian, P., Varghese, D., Singh, D., & Maskell, D. (2019). Generalized Majority Voter Design Method for N-Modular Redundant Systems Used in Mission- and Safety-Critical Applications. Computers, 8(1), 10. doi:10.3390/computers8010010Capella, J. V., Bonastre, A., Ors, R., & Peris, M. (2014). A step forward in the in-line river monitoring of nitrate by means of a wireless sensor network. Sensors and Actuators B: Chemical, 195, 396-403. doi:10.1016/j.snb.2014.01.039Cuartero, M., Colozza, N., Fernández-Pérez, B. M., & Crespo, G. A. (2020). Why ammonium detection is particularly challenging but insightful with ionophore-based potentiometric sensors – an overview of the progress in the last 20 years. The Analyst, 145(9), 3188-3210. doi:10.1039/d0an00327aBembe, M., Abu-Mahfouz, A., Masonta, M., & Ngqondi, T. (2019). A survey on low-power wide area networks for IoT applications. Telecommunication Systems, 71(2), 249-274. doi:10.1007/s11235-019-00557-9Freiser, H. (Ed.). (1980). Ion-Selective Electrodes in Analytical Chemistry. doi:10.1007/978-1-4684-3776-8Peris, M., Bonastre, A., & Ors, R. (1998). Distributed expert system for the monitoring and control of chemical processes. Laboratory Robotics and Automation, 10(3), 163-168. doi:10.1002/(sici)1098-2728(1998)10:33.0.co;2-2Carminati, M., Turolla, A., Mezzera, L., Di Mauro, M., Tizzoni, M., Pani, G., … Antonelli, M. (2020). A Self-Powered Wireless Water Quality Sensing Network Enabling Smart Monitoring of Biological and Chemical Stability in Supply Systems. Sensors, 20(4), 1125. doi:10.3390/s20041125Nakas, C., Kandris, D., & Visvardis, G. (2020). Energy Efficient Routing in Wireless Sensor Networks: A Comprehensive Survey. Algorithms, 13(3), 72. doi:10.3390/a13030072Capella, J. V., Bonastre, A., Campelo, J. C., Ors, R., & Peris, M. (2020). IoT & environmental analytical chemistry: Towards a profitable symbiosis. Trends in Environmental Analytical Chemistry, 27, e00095. doi:10.1016/j.teac.2020.e00095Pretsch, E. (2007). The new wave of ion-selective electrodes. TrAC Trends in Analytical Chemistry, 26(1), 46-51. doi:10.1016/j.trac.2006.10.006STM Microelectronics https://www.st.com/content/st_com/en/products/microcontrollers-microprocessors/stm32-32-bit-arm-cortex-mcus/stm32-ultra-low-power-mcus/stm32l4-series/stm32l4x2/stm32l422cb.htmlAnalog Devices https://www.analog.com/media/en/technical-documentation/data-sheets/AD524.pdfCapella, J. V., Bonastre, A., Ors, R., & Peris, M. (2010). A Wireless Sensor Network approach for distributed in-line chemical analysis of water. Talanta, 80(5), 1789-1798. doi:10.1016/j.talanta.2009.10.025Bonastre, A., Capella, J. V., Ors, R., & Peris, M. (2012). In-line monitoring of chemical-analysis processes using Wireless Sensor Networks. TrAC Trends in Analytical Chemistry, 34, 111-125. doi:10.1016/j.trac.2011.11.009Mei-Chen Hsueh, Tsai, T. K., & Iyer, R. K. (1997). Fault injection techniques and tools. Computer, 30(4), 75-82. doi:10.1109/2.58515

Cuestiones y problemas de análisis de alimentos

Este libro contiene una colección de 100 ejercicios completamente resueltos que ayudarán al estudiante a reforzar su conocimiento sobre la materia análisis de alimentos.Los ejercicios están pensados para que se pongan en práctica los conocimientos aprendidos y para ello se estructura en dos tipos diferenciados:por un lado,50 problemas numéricos con los que se practicará cómo interpretar los valores obtenidos en las medias experimentales en el laboratorio y la expresión del resultado final de forma correcta;por otro lado,50 ejercicios que plantean diferentes cuestiones sobre la materia que harán al estudiando razonar sobre los métodos de análisis conocidos y a comprobar su grado de comprensiónPeris Tortajada, M. (2017). Cuestiones y problemas de análisis de alimentos. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/90324EDITORIA

Smart sensors in environmental/water quality monitoring using IoT and cloud services

[EN] The growing social awareness and consequent concern for the environment has driven environmental analytical chemistry to a position of great prominence. In recent times, this position has translated into taking advantage of the great benefits provided by cloud computing and the Internet of Things (IoT), which are especially appropriate when devices such as chemical sensors are used. The use of such sensors is very common when in situ monitoring of environmental parameters is performed, but until recently, it was limited to the deployment of a small number of sensors. Currently, this approach has given way to genuine smart sensing systems (for instance, fully consolidated wireless sensor networks) that are able to provide a substantial amount of information. This type of sensor (the so-called smart sensor) is fundamentally characterized by (a) low consumption, versatility, and autonomy, (b) ease of integration with cloud solutions, (c) durability and reliability of IoT platforms and sensors, and (d) easy installation and deployment of sensor nodes. For all these reasons, and given the increasing importance and use of this type of device, a revision of the recent literature relating the development of smart sensors with environmental issues has been conducted, with major contributions being discussed, most notably those addressing the continuous in-line monitoring of water quality.Garrido-Momparler, V.; Peris Tortajada, M. (2022). Smart sensors in environmental/water quality monitoring using IoT and cloud services. Trends in Environmental Analytical Chemistry. 35:1-7. https://doi.org/10.1016/j.teac.2022.e00173173

Measuring the effects of a hydrogen peroxide mouth rinse on breath alcohol values.

[EN] The high consumption of alcoholic drinks has become acceptable in many societies and is often promoted by commercials. Unfortunately, many people risk their lives by driving drunk. They even try to outsmart breathalyzer tests, for example, using a novel procedure based on the partial oxidation of expired breathed ethanol after rinsing the mouth with diluted hydrogen peroxide. To check the validity of this procedure, the different variables involved in the process were tested: the type of alcoholic beverage, the amount of ethanol swallowed, and the time elapsed between consumption and mouth rinsing. Our ultimate aim was to measure the effects of this process. If the mouth rinse succeeds in masking a drinker's true alcohol level, then further study of possible remedies is needed to prevent such fraud. However, if the rinsing proves to have no effect, then this work could help strengthen the integrity of the breathalyzer test and its ability to deter drivers from overdrinking. The final conclusion, after all the experiments, is that a reduction in the alcohol level is observed with the use of hydrogen peroxide as a mouthwash before performing a breathalyzer test.Nieto, A.; Chirivella González, V.; Peris Tortajada, M. (2022). Measuring the effects of a hydrogen peroxide mouth rinse on breath alcohol values. Heliyon. 8(4):1-6. https://doi.org/10.1016/j.heliyon.2022.e09274168

TECHNICAL SKETCHING ACCORDING TO THE ISO DRAWING STANDARDS

Drawing standards are the written rules that establish the conventions to be applied in the representation of engineering components for designing, manufacturing and quality control purposes. These rules integrate a common language for the Graphic Engineering field, and make possible the transmission of graphical information among different professionals, regardless of their country of origin. "Technical sketching according to the ISO drawing standards" explains, by means of multiple examples and detailed comments, the essential and most important drawing standards published by the International Standards Organization (ISO). Firstly, this book exposes the employment of the basic rules for graphical representation, conventional views, non-conventional views, cross-sections, sections and dimensions. Secondly, the representation of threads and assemblies is described. Finally, the integration of roughness requirements, size tolerance and geometric tolerance in technical drawings is approached.Defez Garcia, B.; Peris Fajarnes, G.; Rubió Sanvalero, CM.; Tortajada Montañana, I. (2015). TECHNICAL SKETCHING ACCORDING TO THE ISO DRAWING STANDARDS. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/66801EDITORIA

A step forward in the in-line river monitoring of nitrate by means of a wireless sensor network

This paper is based on our previous work consisting of the development and deployment of a wireless sensor network for the continuous in-line monitoring of the content of nitrates in a river in Eastern Spain. We present new contributions that significantly enhance its applicability, improve its features, and increase its reliability and useful life. For this purpose, an expert system has been developed in order to improve the features of the whole system operation in an intelligent, flexible, user friendly way. This expert system offers several policies to optimize the times at which measurements are to be carried out (and sent), sampling frequency being altered according to the system evolution, the user preferences and the application features. The implemented policies are as follows: (a) periodic transmission; (b) gradient transmission; (c) user request and (d) peer request. Additionally, in order to increase the reliability of the system, a triple modular redundant transducer in each sensor has been implemented, increasing dependability of the system with a very small affection of cost and consumption. Prior to the field trials, some laboratory experiments have been performed for parameter adjustment and checking purposes. As in the previous work, the proposed system has been deployed along a certain stretch of the river, its operation being studied and validated.Capella Hernández, JV.; Bonastre Pina, AM.; Ors Carot, R.; Peris Tortajada, M. (2014). A step forward in the in-line river monitoring of nitrate by means of a wireless sensor network. Sensors and Actuators B: Chemical. 195:396-403. doi:10.1016/j.snb.2014.01.039S39640319

In-line monitoring of chemical analysis processes using Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are very promising tools in the advanced automation of chemical-analysis processes. Basically, they are formed by many small devices - called sensor nodes or motes - that can obtain information from the surrounding area using appropriate transducers, and communicate it by suitable wireless-transmission systems. In this article, we study both the application of WSN technology to analytical chemistry and the new research fields for analytical chemistry opened up by the success of WSN applications. A basic "chemical-applied" description of WSNs is followed by the reasons for their implementation and their use in chemical-analysis processes, and comments on the most relevant contributions developed so far. Finally, this article also deals with future trends in this field. Key research challenges to be addressed to deliver remote, wireless, chemosensing systems include the development of low-cost, low-consumption sensors. (C) 2012 Elsevier Ltd. All rights reserved.Bonastre Pina, AM.; Capella Hernández, JV.; Ors Carot, R.; Peris Tortajada, M. (2012). In-line monitoring of chemical analysis processes using Wireless Sensor Networks. Trends in Analytical Chemistry. 34:111-125. doi:10.1016/j.trac.2011.11.009S1111253