Recently, low-dimensional (1D, 2D) nanostructured materials have been attracting more and more interest as building blocks for innovative systems. Metal oxide nanowires are one of the most widely used materials for solid-state gas sensors, as they are simple to make, inexpensive, and sensitive to a wide range of gases and volatiles. Unfortunately, their broad sensitivity has a price to pay, which is very low selectivity. Fortunately, this flaw is not a problem for all applications. Where the boundary conditions are defined and “simple” (only the presence of a target gas is expected, without any interfering gases), a single traditional chemiresistor may be the best choice, while in cases where the variables are many, it is better to use an intelligent system. In this paper, we will show a resistive sensor based on a single SnO2 nanowire which, working at three temperatures (200, 250, and 300 °C), is able to detect tens of ppb of ammonia (30 ppb at 300 °C). The limit of detection (LoD) was calculated as 3 N/S, where N is the standard deviation of the sensor signal in air and S is the sensor sensitivity. We will show that the performance of this nanosensor is excellent and can be used in various applications, including agri-food quality monitoring. We will demonstrate that the SnO2 nanowire in a thermal gradient can act as a nano-electronic nose thanks to machine learning algorithms. The single nanowire-based sensor can estimate the total viable count with an error of 2.32% on mackerel fish samples stored at room temperature (25 °C) and in a fridge (4 °C). The integration of such a small (less than one square mm) and cheap device into the food supply chain would greatly reduce waste and the frequency of food poisoning.
{"title":"From Single Nanowires to Smart Systems: Different Ways to Assess Food Quality","authors":"M. Tonezzer, F. Biasioli, F. Gasperi","doi":"10.3390/csac2021-10605","DOIUrl":"https://doi.org/10.3390/csac2021-10605","url":null,"abstract":"Recently, low-dimensional (1D, 2D) nanostructured materials have been attracting more and more interest as building blocks for innovative systems. Metal oxide nanowires are one of the most widely used materials for solid-state gas sensors, as they are simple to make, inexpensive, and sensitive to a wide range of gases and volatiles. Unfortunately, their broad sensitivity has a price to pay, which is very low selectivity. Fortunately, this flaw is not a problem for all applications. Where the boundary conditions are defined and “simple” (only the presence of a target gas is expected, without any interfering gases), a single traditional chemiresistor may be the best choice, while in cases where the variables are many, it is better to use an intelligent system. In this paper, we will show a resistive sensor based on a single SnO2 nanowire which, working at three temperatures (200, 250, and 300 °C), is able to detect tens of ppb of ammonia (30 ppb at 300 °C). The limit of detection (LoD) was calculated as 3 N/S, where N is the standard deviation of the sensor signal in air and S is the sensor sensitivity. We will show that the performance of this nanosensor is excellent and can be used in various applications, including agri-food quality monitoring. We will demonstrate that the SnO2 nanowire in a thermal gradient can act as a nano-electronic nose thanks to machine learning algorithms. The single nanowire-based sensor can estimate the total viable count with an error of 2.32% on mackerel fish samples stored at room temperature (25 °C) and in a fridge (4 °C). The integration of such a small (less than one square mm) and cheap device into the food supply chain would greatly reduce waste and the frequency of food poisoning.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73507332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mafalda Reis-Pereira, R. C. Martins, Aníbal Filipe Silva, F. Tavares, F. Santos, Mário Cunha
This study analyzed the potential of proximal optical sensing as an effective approach for early disease detection. A compact, modular sensing system, combining direct UV–Vis spectroscopy with optical fibers, supported by a principal component analysis (PCA), was applied to evaluate the modifications promoted by the bacteria Xanthomonas euvesicatoria in tomato leaves (cv. cherry). Plant infection was achieved by spraying a bacterial suspension (108 CFU mL−1) until run-off occurred, and a similar approach was followed for the control group, where only water was applied. A total of 270 spectral measurements were performed on leaves, on five different time instances, including pre- and post-inoculation measurements. PCA was then applied to the acquired data from both healthy and inoculated leaves, which allowed their distinction and differentiation, three days after inoculation, when unhealthy plants were still asymptomatic.
{"title":"Unravelling Plant-Pathogen Interactions: Proximal Optical Sensing as an Effective Tool for Early Detect Plant Diseases","authors":"Mafalda Reis-Pereira, R. C. Martins, Aníbal Filipe Silva, F. Tavares, F. Santos, Mário Cunha","doi":"10.3390/csac2021-10560","DOIUrl":"https://doi.org/10.3390/csac2021-10560","url":null,"abstract":"This study analyzed the potential of proximal optical sensing as an effective approach for early disease detection. A compact, modular sensing system, combining direct UV–Vis spectroscopy with optical fibers, supported by a principal component analysis (PCA), was applied to evaluate the modifications promoted by the bacteria Xanthomonas euvesicatoria in tomato leaves (cv. cherry). Plant infection was achieved by spraying a bacterial suspension (108 CFU mL−1) until run-off occurred, and a similar approach was followed for the control group, where only water was applied. A total of 270 spectral measurements were performed on leaves, on five different time instances, including pre- and post-inoculation measurements. PCA was then applied to the acquired data from both healthy and inoculated leaves, which allowed their distinction and differentiation, three days after inoculation, when unhealthy plants were still asymptomatic.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"132 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76110541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular nanoprobes with intrinsic enzyme-like activity represent a new wave of technology for rapid and sensitive detection of molecular targets. This work reports synthesis and characterization of novel and well-dispersed europium-doped ceria nanocrystals (EuCe NCs) with self-integrated catalytic and fluorescence sensing functions. The NCs have an average size of ∼5 nm and exhibit bright and stable fluorescence for more than 6 months in aqueous media. Their dual cooperative function as both a catalyst and fluorescent probe was explored to develop a universally applicable fluorescence-based biosensing method to monitor enzyme reactions and quantitatively measure clinically relevant molecules. Sensing capabilities are demonstrated for detection of H2O2, glucose/glucose oxidase, lactate/lactate oxidase, phosphatase activity, and the catecholamine neurotransmitter, dopamine. Results indicate that EuCe NCs not only provide high enzyme-mimetic activity, but also impart direct fluorescence sensing ability enabling all-in-one recognition, catalytic amplification, and the detection of biomolecular targets. The EuCe nanozyme offers a stable alternative to the more complex systems based on the combined use of natural enzymes and fluorescent dyes. The high stability and fluorescence detection capabilities demonstrate that EuCe NCs have the potential to be used as a generic platform in chemical and biological sensing and bioimaging applications.
{"title":"Europium-Doped Ceria Nanocrystals as Nanozyme Fluorescent Probes for Biosensing","authors":"Ali Othman, A. Hayat, S. Andreescu","doi":"10.3390/csac2021-10549","DOIUrl":"https://doi.org/10.3390/csac2021-10549","url":null,"abstract":"Molecular nanoprobes with intrinsic enzyme-like activity represent a new wave of technology for rapid and sensitive detection of molecular targets. This work reports synthesis and characterization of novel and well-dispersed europium-doped ceria nanocrystals (EuCe NCs) with self-integrated catalytic and fluorescence sensing functions. The NCs have an average size of ∼5 nm and exhibit bright and stable fluorescence for more than 6 months in aqueous media. Their dual cooperative function as both a catalyst and fluorescent probe was explored to develop a universally applicable fluorescence-based biosensing method to monitor enzyme reactions and quantitatively measure clinically relevant molecules. Sensing capabilities are demonstrated for detection of H2O2, glucose/glucose oxidase, lactate/lactate oxidase, phosphatase activity, and the catecholamine neurotransmitter, dopamine. Results indicate that EuCe NCs not only provide high enzyme-mimetic activity, but also impart direct fluorescence sensing ability enabling all-in-one recognition, catalytic amplification, and the detection of biomolecular targets. The EuCe nanozyme offers a stable alternative to the more complex systems based on the combined use of natural enzymes and fluorescent dyes. The high stability and fluorescence detection capabilities demonstrate that EuCe NCs have the potential to be used as a generic platform in chemical and biological sensing and bioimaging applications.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87372623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Organic semiconductors can be used as highly sensitive fluorescent sensors for the detection of trace-level vapours of nitroaromatic explosives. This involves fluorescence quenching of the sensors and indicates the presence of explosives in the surrounding environment. However, for many organic fluorescent sensors, the quenching of fluorescence is irreversible and imposes a limitation in terms of the reusability of the sensors. Here, we present a study of thermal desorption of 2,4-DNT from thin-film explosives sensors made from the commercial fluorescent polymers Super Yellow and poly(9-vinyl carbazole). Thermal cycling of the sensor results in recovery of fluorescence, thereby making them reusable.
{"title":"Thermal Desorption of Explosives Vapour from Organic Fluorescent Sensors","authors":"Edward B Ogugu, R. Gillanders, G. Turnbull","doi":"10.3390/csac2021-10559","DOIUrl":"https://doi.org/10.3390/csac2021-10559","url":null,"abstract":"Organic semiconductors can be used as highly sensitive fluorescent sensors for the detection of trace-level vapours of nitroaromatic explosives. This involves fluorescence quenching of the sensors and indicates the presence of explosives in the surrounding environment. However, for many organic fluorescent sensors, the quenching of fluorescence is irreversible and imposes a limitation in terms of the reusability of the sensors. Here, we present a study of thermal desorption of 2,4-DNT from thin-film explosives sensors made from the commercial fluorescent polymers Super Yellow and poly(9-vinyl carbazole). Thermal cycling of the sensor results in recovery of fluorescence, thereby making them reusable.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85183618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Lete, M. Marin, F. D. del Campo, I. Diaconu, Stelian Lupu
In this work, the characterization and the electro-analytical applications of antimony tin oxide (ATO)–Prussian blue (PB) screen printed electrodes (SPE) are presented. The ATO conducting particles have been used recently in the development of screen-printed electrodes due to their excellent spectroelectrochemical properties. PB is a transition metal hexacyanoferrate with high electrocatalytic properties towards various biologically active compounds like hydrogen peroxide, besides its outstanding electrochromic properties. A combination of ATO and PB ingredients into a screen-printing paste provided a versatile and cost-effective way in the development of novel electrode materials for electrochemical sensing. The ATO-PB electrode material displayed good electrochemical properties demonstrated by means of cyclic voltammetry and electrochemical impedance measurements. In addition, the PB provided a high selectivity towards potassium ions in solution due to its zeolitic structures and excellent redox behavior. The cyclic voltammetric responses recorded at the ATO-PB-SPE device in the presence of potassium ions revealed a linear dependence of the cathodic peak current and cathodic peak potential of the Prussian blue/Everitt’s salt redox system on the potassium concentrations ranging from 0.1 to 10 mM. This finding could be exploited in the development of an electrochemical sensor for electro-inactive chemical species. The potential application of the ATO-PB electrode in the electrochemical sensing of electro-active species like caffeic acid was also studied. An increase of the anodic peak current of the PB/ES redox wave in the presence of caffeic acid was observed. These results point out to the potential analytical applications of the ATO-PB electrode in the sensing of both electro-active and electro-inactive species.
{"title":"Antimony Tin Oxide—Prussian Blue Screen-Printed Electrodes for Electrochemical Sensing of Potassium Ions","authors":"C. Lete, M. Marin, F. D. del Campo, I. Diaconu, Stelian Lupu","doi":"10.3390/csac2021-10639","DOIUrl":"https://doi.org/10.3390/csac2021-10639","url":null,"abstract":"In this work, the characterization and the electro-analytical applications of antimony tin oxide (ATO)–Prussian blue (PB) screen printed electrodes (SPE) are presented. The ATO conducting particles have been used recently in the development of screen-printed electrodes due to their excellent spectroelectrochemical properties. PB is a transition metal hexacyanoferrate with high electrocatalytic properties towards various biologically active compounds like hydrogen peroxide, besides its outstanding electrochromic properties. A combination of ATO and PB ingredients into a screen-printing paste provided a versatile and cost-effective way in the development of novel electrode materials for electrochemical sensing. The ATO-PB electrode material displayed good electrochemical properties demonstrated by means of cyclic voltammetry and electrochemical impedance measurements. In addition, the PB provided a high selectivity towards potassium ions in solution due to its zeolitic structures and excellent redox behavior. The cyclic voltammetric responses recorded at the ATO-PB-SPE device in the presence of potassium ions revealed a linear dependence of the cathodic peak current and cathodic peak potential of the Prussian blue/Everitt’s salt redox system on the potassium concentrations ranging from 0.1 to 10 mM. This finding could be exploited in the development of an electrochemical sensor for electro-inactive chemical species. The potential application of the ATO-PB electrode in the electrochemical sensing of electro-active species like caffeic acid was also studied. An increase of the anodic peak current of the PB/ES redox wave in the presence of caffeic acid was observed. These results point out to the potential analytical applications of the ATO-PB electrode in the sensing of both electro-active and electro-inactive species.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90178426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Salvo-Comino, C. Pérez-González, F. Martín-Pedrosa, C. García-Cabezón, M. L. Rodriguez-Mendez
The integration of silver nanomaterials as electron mediators in electrochemical biosensors can be crucial to improve the affinity with biomolecules and the electrochemical response. In this work, two voltammetric bioelectronics tongues (bioET) formed by biosensors based on the combination of enzymes with silver nanoparticles (AgNPs) (bioET-1) or silver nanowires (AgNWs) (bioET-2) have been developed and used to analyze milks. Each array was formed by four biosensors formed by enzymes (glucose oxidase, galactose oxidase, β-galactosidase and a blank), capable to detect compounds usually found in milks. Principal component analysis (PCA) has revealed the ability of both biosensor systems to discriminate between milk samples with different fat contents, but with some differences, attributed to the structure employed in the detection.
{"title":"Silver Nanomaterials as Electron Mediators in a Bio-Electronic Tongue Dedicated to the Analysis of Milks. The Role of the Aspect Ratio of Nanoparticles vs. Nanowires","authors":"C. Salvo-Comino, C. Pérez-González, F. Martín-Pedrosa, C. García-Cabezón, M. L. Rodriguez-Mendez","doi":"10.3390/csac2021-10554","DOIUrl":"https://doi.org/10.3390/csac2021-10554","url":null,"abstract":"The integration of silver nanomaterials as electron mediators in electrochemical biosensors can be crucial to improve the affinity with biomolecules and the electrochemical response. In this work, two voltammetric bioelectronics tongues (bioET) formed by biosensors based on the combination of enzymes with silver nanoparticles (AgNPs) (bioET-1) or silver nanowires (AgNWs) (bioET-2) have been developed and used to analyze milks. Each array was formed by four biosensors formed by enzymes (glucose oxidase, galactose oxidase, β-galactosidase and a blank), capable to detect compounds usually found in milks. Principal component analysis (PCA) has revealed the ability of both biosensor systems to discriminate between milk samples with different fat contents, but with some differences, attributed to the structure employed in the detection.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88932723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bernabé Nuñez-Estevez, T. Finimundy, M. Carpena, M. Barral-Martinez, R. Calhelha, T. Pires, P. Otero, P. García-Pérez, J. Simal-Gándara, I. Ferreira, M. Prieto, L. Barros
In this work, the chemical and nutritional composition of three Amaranthaceae species (Alternanthera sessilis, Dicliptera chinensis, and Dysphania ambrosioides) was studied. The results showed a differential flavonoid content in the three species: A. sessilis and D. ambrosioides showed similar flavonoid contents (15.1 ± 0.6 and 15.1 ± 0.1 mg/g extract, respectively), followed by D. chinensis (11.4 ± 0.1 mg/g extract). On the other hand, the nutritional results showed a high protein content in all species (16.9–13.9 ± 0.1 g/100 g dw) and revealed the presence of organic acids, such as oxalic and succinic acid. Therefore, bioactive compounds, together with protein and organic acids, could be of great value to the food industry.
{"title":"Bioactive Compound Profiling and Nutritional Composition of Three Species from the Amaranthaceae Family","authors":"Bernabé Nuñez-Estevez, T. Finimundy, M. Carpena, M. Barral-Martinez, R. Calhelha, T. Pires, P. Otero, P. García-Pérez, J. Simal-Gándara, I. Ferreira, M. Prieto, L. Barros","doi":"10.3390/csac2021-10563","DOIUrl":"https://doi.org/10.3390/csac2021-10563","url":null,"abstract":"In this work, the chemical and nutritional composition of three Amaranthaceae species (Alternanthera sessilis, Dicliptera chinensis, and Dysphania ambrosioides) was studied. The results showed a differential flavonoid content in the three species: A. sessilis and D. ambrosioides showed similar flavonoid contents (15.1 ± 0.6 and 15.1 ± 0.1 mg/g extract, respectively), followed by D. chinensis (11.4 ± 0.1 mg/g extract). On the other hand, the nutritional results showed a high protein content in all species (16.9–13.9 ± 0.1 g/100 g dw) and revealed the presence of organic acids, such as oxalic and succinic acid. Therefore, bioactive compounds, together with protein and organic acids, could be of great value to the food industry.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88275307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Achraf El Mohajir, Jean-Baptiste Sanchez, M. Arab Pour Yazdi, O. Heintz, N. Martin
Indoor air quality is a topic of major importance for public health. Among the numerous chemical compounds that can be found in indoor air, BTEX (i.e., benzene, toluene, ethylbenzene, and xylene) is considered one of the most toxic volatile organic compounds (VOCs). The present contribution is focused on the use of an original approach to produce nanostructured materials based on tin oxide with unexplored features, especially for gas sensors. In this work, we combine two physical vapor deposition techniques based, first, on a pulsing injection of the reactive gas during the deposition and second focused on the glancing angle deposition (GLAD) technique, which enables the structuring of various architectures. These active layers are deposited on a micro-hotplate to produce micro-chemical gas sensors for the detection of BTEX. Here, we have demonstrated the utility of using the GLAD deposition technique and the role of sputtering pressure in obtaining porous sensitive thin films. In particular, we established relationships between deposition parameters and gas sensing performances.
{"title":"Detection of Indoor Air Pollutants Using Reactive Sputtering/GLAD of Tin Oxide Thin Films","authors":"Achraf El Mohajir, Jean-Baptiste Sanchez, M. Arab Pour Yazdi, O. Heintz, N. Martin","doi":"10.3390/csac2021-10548","DOIUrl":"https://doi.org/10.3390/csac2021-10548","url":null,"abstract":"Indoor air quality is a topic of major importance for public health. Among the numerous chemical compounds that can be found in indoor air, BTEX (i.e., benzene, toluene, ethylbenzene, and xylene) is considered one of the most toxic volatile organic compounds (VOCs). The present contribution is focused on the use of an original approach to produce nanostructured materials based on tin oxide with unexplored features, especially for gas sensors. In this work, we combine two physical vapor deposition techniques based, first, on a pulsing injection of the reactive gas during the deposition and second focused on the glancing angle deposition (GLAD) technique, which enables the structuring of various architectures. These active layers are deposited on a micro-hotplate to produce micro-chemical gas sensors for the detection of BTEX. Here, we have demonstrated the utility of using the GLAD deposition technique and the role of sputtering pressure in obtaining porous sensitive thin films. In particular, we established relationships between deposition parameters and gas sensing performances.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77929601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ítala M. G. Marx, Nuno F. Rodrigues, A. C. Veloso, J. Pereira, A. M. Peres
The present study investigated the effect of malaxation times (Mt) (0, 15, 30, 45 and 60 min), during the industrial extraction of cv. Arbequina oils at 25 °C on total phenolic content of olive pastes. Additionally, the possibility of applying a lab-made potentiometric electronic tongue (E-tongue), comprising 40 lipid/polymer sensor membranes with cross sensitivity, to discriminate the olive pastes according to the Mt, was evaluated. The results pointed out that the olive pastes’ total phenolic contents significantly decreased (p-value < 0.001, one-way ANOVA) with the increase of the Mt (from 2.21 ± 0.02 to 1.99 ± 0.03 g gallic acid equivalents/kg olive paste), there being observed a linear decreasing trend (R-Pearson = −0.910). These findings may be tentatively attributed to the migration of the phenolic compounds from the olive pastes to the extracted oil and water phases, during the malaxation process. Finally, the E-tongue signals, acquired during the analysis of the olive pastes’ methanolic extracts (methanol:water, 80:20 v/v), together with a linear discriminant analysis (LDA), coupled with a simulated annealing (SA) algorithm, allowed us to establish a successful classification model. The E-tongue-LDA-SA model, based on 11 selected non-redundant sensors, allowed us to correctly discriminate all the studied olive pastes according to the Mt (sensitivities of 100% for training and leave-one-out cross-validation). The satisfactory performance of the E-tongue could be tentatively explained by the known capability of lipid/polymeric sensor membranes to interact with phenolic compounds, through electrostatic interactions and/or hydrogen bonds, which total content depended on the Mt.
{"title":"Evaluation of the Effect of Extracted Time Conditions on the Phenolic Content of Olive Pastes from cv. Arbequina and Discrimination Using a Lab-Made Potentiometric Electronic Tongue","authors":"Ítala M. G. Marx, Nuno F. Rodrigues, A. C. Veloso, J. Pereira, A. M. Peres","doi":"10.3390/csac2021-10556","DOIUrl":"https://doi.org/10.3390/csac2021-10556","url":null,"abstract":"The present study investigated the effect of malaxation times (Mt) (0, 15, 30, 45 and 60 min), during the industrial extraction of cv. Arbequina oils at 25 °C on total phenolic content of olive pastes. Additionally, the possibility of applying a lab-made potentiometric electronic tongue (E-tongue), comprising 40 lipid/polymer sensor membranes with cross sensitivity, to discriminate the olive pastes according to the Mt, was evaluated. The results pointed out that the olive pastes’ total phenolic contents significantly decreased (p-value < 0.001, one-way ANOVA) with the increase of the Mt (from 2.21 ± 0.02 to 1.99 ± 0.03 g gallic acid equivalents/kg olive paste), there being observed a linear decreasing trend (R-Pearson = −0.910). These findings may be tentatively attributed to the migration of the phenolic compounds from the olive pastes to the extracted oil and water phases, during the malaxation process. Finally, the E-tongue signals, acquired during the analysis of the olive pastes’ methanolic extracts (methanol:water, 80:20 v/v), together with a linear discriminant analysis (LDA), coupled with a simulated annealing (SA) algorithm, allowed us to establish a successful classification model. The E-tongue-LDA-SA model, based on 11 selected non-redundant sensors, allowed us to correctly discriminate all the studied olive pastes according to the Mt (sensitivities of 100% for training and leave-one-out cross-validation). The satisfactory performance of the E-tongue could be tentatively explained by the known capability of lipid/polymeric sensor membranes to interact with phenolic compounds, through electrostatic interactions and/or hydrogen bonds, which total content depended on the Mt.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90105200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Carreira-Casais, M. Carpena, A. Pereira, F. Chamorro, A. Soria-López, Pascual García Pérez, P. Otero, H. Cao, Jianbo Xiao, J. Simal-Gándara, M. Prieto
Ultrasound-assisted extraction (UAE) is a novel methodology, belonging to the so-called “Green Chemistry”, which has gained interest in recent years due to the potential to recover bioactive compounds, especially those from plant matrices. It is widely recognized that the extraction of molecules by UAE gives rise to higher or similar yields than those obtained by traditional extraction methods. UAE has certain advantages inherent to Green Chemistry extraction methods, such as short extraction time and low solvent consumption. The aim of this review is to critically present the different variables and parameters that can be modified in UAE, such as ultrasound power, time, temperature, solvent, and solid to solvent ratio that influence yield and extraction performance.
{"title":"Critical Variables Influencing the Ultrasound-Assisted Extraction of Bioactive Compounds—A Review","authors":"A. Carreira-Casais, M. Carpena, A. Pereira, F. Chamorro, A. Soria-López, Pascual García Pérez, P. Otero, H. Cao, Jianbo Xiao, J. Simal-Gándara, M. Prieto","doi":"10.3390/csac2021-10562","DOIUrl":"https://doi.org/10.3390/csac2021-10562","url":null,"abstract":"Ultrasound-assisted extraction (UAE) is a novel methodology, belonging to the so-called “Green Chemistry”, which has gained interest in recent years due to the potential to recover bioactive compounds, especially those from plant matrices. It is widely recognized that the extraction of molecules by UAE gives rise to higher or similar yields than those obtained by traditional extraction methods. UAE has certain advantages inherent to Green Chemistry extraction methods, such as short extraction time and low solvent consumption. The aim of this review is to critically present the different variables and parameters that can be modified in UAE, such as ultrasound power, time, temperature, solvent, and solid to solvent ratio that influence yield and extraction performance.","PeriodicalId":9815,"journal":{"name":"Chemistry Proceedings","volume":"35 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84955683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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