Chemistry Proceedings

Open AccessProceeding Paper

Precipitation of Iron Oxide in Hydrogel with Superparamagnetic and Stimuli-Responsive Properties

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Chem. Proc. 2021, 5(1), 49; https://doi.org/10.3390/chemproc2021005049 - 17 Dec 2021

Abstract

In this work, we present a template-based preparation of iron oxide-containing hydrogels (ferrogels) with ionic sensitive and superparamagnetic properties. The influence of the cross-linked template polyacrylamide and the concentration of the iron salts and sodium hydroxide on the precipitation of the iron oxide [...] Read more.

In this work, we present a template-based preparation of iron oxide-containing hydrogels (ferrogels) with ionic sensitive and superparamagnetic properties. The influence of the cross-linked template polyacrylamide and the concentration of the iron salts and sodium hydroxide on the precipitation of the iron oxide particles is investigated with respect to the stability of the ferrogels. Scanning electron microscope images show cubic particles, which can be semiquantitatively classified in three groups of particle size with respect to the dilution level. Magnetic hysteresis curves reveal a sigmoidal shape without remanence and coercivity for all samples. The higher cross-linked ferrogels, in comparison with the lower cross-linked ferrogels, possess a steady-state degree of swelling in ultrapure water and a stimuli-sensitive deswelling over a wide range of varying ionic strengths. Thus, they are suitable candidates for applications in sensing and microfluidics. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Electrochemical Measurement System for Chlorides in Drinking and Wastewater

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Diana A. Toriz-Gutiérrez

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Humberto Ramírez-Gasca

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Luis E. Cárdenas-Galindo

and

Eloisa Gallegos-Arellano

Chem. Proc. 2021, 5(1), 46; https://doi.org/10.3390/chemproc2021005046 - 17 Dec 2021

Abstract

This paper presents a system for the measurement of chlorides in drinking and wastewater, based on an electrochemical process using a selective electrode as a transducer, which was developed by this group. The measurement for the concentration is carried out by introducing the [...] Read more.

This paper presents a system for the measurement of chlorides in drinking and wastewater, based on an electrochemical process using a selective electrode as a transducer, which was developed by this group. The measurement for the concentration is carried out by introducing the implemented electrode (considered as reference) in the sample that will be analyzed; then a current is passed producing a potential difference in the system. Different aqueous solutions of sodium chloride (NaCl) were used, ranging between 35 and 3546 µg of chloride ions (Cl⁻). As a data acquisition and monitoring system for the analysis, an ATmega 328P microcontroller was used as the main capture element for subsequent interpretation through graphics. The experimental results show that it was possible to detect a potential difference in the electrochemical measurement system that corresponded to 35 µg of chloride ions (Cl⁻), making clear the detection process and the selectivity of chloride ions. It is important to mention that with this measurement system and the applied methodology, results are obtained in real time using a small sample volume and without generate ng extra liquid waste, compared to the application of the traditional analytical titrimetric method. Finally, this chloride measurement system is inexpensive and can be used in drinking and wastewater measurements. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Polysaccharide-Based Organic Frameworks with Embedded Nanoparticles: Advanced SPR Study on the Antiviral Activity of Gold Composites Derived from Glucuronoxylomannan

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Chem. Proc. 2021, 5(1), 38; https://doi.org/10.3390/CSAC2021-10475 - 15 Dec 2021

Abstract

The nanosized composites based on the natural polysaccharides and nanoparticles of noble metals are promising candidates for efficient antiviral drugs. However, the complexity of such objects, their diversity and novelty necessitate the development of new analytical methods for investigation of such supramolecular architectures. [...] Read more.

The nanosized composites based on the natural polysaccharides and nanoparticles of noble metals are promising candidates for efficient antiviral drugs. However, the complexity of such objects, their diversity and novelty necessitate the development of new analytical methods for investigation of such supramolecular architectures. In this work, which was recently developed for SPR-based instrumentation, the concept of variative refraction (DViFA, density variations in fixed architectures) was used to elucidate the mechanism of the antiviral action of a polysaccharide with gold nanoparticles grown in it. The SPR data were confirmed by direct biological tests: the effect of the native polysaccharide glucuronoxylomannan (GXM) obtained from the fungus Ganoderma adspersum and gold nanocomposites thereon on the infection of Datura stramonium with tobacco mosaic virus (TMV) was investigated. Both drugs suppress the development of viral infections. However, if for high concentrations the characteristic activity of the composite is somewhat lower than for GXM, then with an increase in dilution, the effectiveness of the composite increases significantly, up to a twofold excess. It has been reasonably suggested that the mechanism of antiviral action is associated with the formation of clusters of viruses that are no longer capable of infecting cells. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessConference Report

1st Spring Virtual Meeting on Medicinal Chemistry

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M. Emília Sousa

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M. Matilde Marques

and

M. Amparo F. Faustino

Chem. Proc. 2021, 4(1), 1; https://doi.org/10.3390/chemproc2021004001 - 19 Oct 2021

Abstract

The 1st Spring Virtual Meeting on Medicinal Chemistry was held virtually on 26 May 2021. The event was organized by the Medicinal Chemistry Division of the Portuguese Chemical Society (SPQ) and was endorsed by the European Federation for Medicinal Chemistry and Chemical Biology. [...] Read more.

The 1st Spring Virtual Meeting on Medicinal Chemistry was held virtually on 26 May 2021. The event was organized by the Medicinal Chemistry Division of the Portuguese Chemical Society (SPQ) and was endorsed by the European Federation for Medicinal Chemistry and Chemical Biology. Three plenary lectures were delivered by renowned international scientists, and seven oral communications were presented by young researchers to a significant number of attendees of 20 nationalities. This issue presents the proceedings of this meeting in the form of abstracts for papers presented at the conference. Full article

(This article belongs to the Proceedings of Chemistry Proceedings)

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Open AccessProceeding Paper

Electrochemical Detection of Fenthion Insecticide in Olive Oils by a Sensitive Non-Enzymatic Biomimetic Sensor Enhanced with Metal Nanoparticles

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Chem. Proc. 2021, 5(1), 64; https://doi.org/10.3390/CSAC2021-10773 - 17 Aug 2021

Abstract

Fenthion, an organophosphate insecticide, is a cholinesterase inhibitor and is highly toxic. An electrochemical sensor based on molecularly imprinted polymer is developed here for its detection. For this purpose, 2-aminothiophenol mixed with gold nanoparticles was immobilized on screen-printed gold electrodes. The FEN pattern [...] Read more.

Fenthion, an organophosphate insecticide, is a cholinesterase inhibitor and is highly toxic. An electrochemical sensor based on molecularly imprinted polymer is developed here for its detection. For this purpose, 2-aminothiophenol mixed with gold nanoparticles was immobilized on screen-printed gold electrodes. The FEN pattern was then fixed before being covered with 2-aminothiophenol. Cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy methods were used for the electrochemical characterization. The low detection limit was 0.05 mg/Kg over a range of 0.01–17.3 µg/mL. The sensor was successfully applied for the determination of FEN in olive oil samples with high recovery values. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Nutritional Composition of the Atlantic Seaweeds Ulva rigida, Codium tomentosum, Palmaria palmata and Porphyra purpurea

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Javier Echave

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Catarina Lourenço-Lopes

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Chem. Proc. 2021, 5(1), 67; https://doi.org/10.3390/CSAC2021-10681 - 14 Jul 2021

Abstract

Macroalgae are regarded as a healthy food due to their composition and nutritional properties. In this work, nutritional composition of two green (Ulva rigida, Codium tomentosum) and two red (Palmaria palmata, Porphyra purpurea) edible seaweed was studied. [...] Read more.

Macroalgae are regarded as a healthy food due to their composition and nutritional properties. In this work, nutritional composition of two green (Ulva rigida, Codium tomentosum) and two red (Palmaria palmata, Porphyra purpurea) edible seaweed was studied. Total lipids were measured gravimetrically as evaporated mass after petroleum-ether Soxhlet extraction of samples. In addition, fatty acid profile was determined by gas chromatography coupled to a flame ionization detector (GC-FID). Results showed that all studied species were accounted for very low levels of lipids (<1% dw), but levels of unsaturated fatty acids oleic, linoleic, and linolenic acids were present at high concentrations, with P. palmata displaying the highest quantities (>200 mg C18:1/g extract). In parallel, proteins were quantified following the macro-Kjeldahl method. In this analysis, red algae, especially P. purpurea, showed significant protein content up to 30% DW. Total organic acids were found by ultra-filtration liquid-chromatography coupled to an amperometry detector (UFLC-PAD) after an acid extraction, P. purpurea being the algae with the higher organic acid content (10.61% dw). Minerals were identified and quantified by inductively coupled plasma atomic emission spectroscopy (ICP-OES), suggesting that both algae groups are rich in K and Mg (>15 g/kg), but U. rigida also displayed a remarkable iron content (>1 g Fe/kg). Other detected minerals in minor concentrations were Ca, P or F. Altogether, results corroborate that these edible algae are a good source of nutrients in accordance with literature. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Identification, Quantification, and Method Validation of Anthocyanins

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Paula Garcia-Oliveira

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Antia G. Pereira

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Maria Fraga-Corral

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Catarina Lourenço-Lopes

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Isabel C. F. R. Ferreira

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Jesus Simal-Gandara

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Miguel A. Prieto

Chem. Proc. 2021, 5(1), 43; https://doi.org/10.3390/CSAC2021-10680 - 14 Jul 2021

Abstract

Nowadays, anthocyanins have gained scientific and industrial attention due to their biological activities and coloring properties. In this regard, anthocyanins have been proposed for use in the development of new nutraceutical foods to replace synthetic additives as well as to be value-added ingredients. [...] Read more.

Nowadays, anthocyanins have gained scientific and industrial attention due to their biological activities and coloring properties. In this regard, anthocyanins have been proposed for use in the development of new nutraceutical foods to replace synthetic additives as well as to be value-added ingredients. The aim of this study was to evaluate current data on identification and quantification techniques and the validation process of such methods. Our results showed that anthocyanins have been identified by different methods, including nuclear magnetic resonance and chromatography-based techniques. Although problems have been described in this validation, most of the reports showed positive results on the validation parameters, suggesting that the current analytical technology offers a satisfactory identification and quantification of anthocyanins. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

An Optical Fiber Sensor for Hg²⁺ Detection Based on the LSPR of Silver and Gold Nanoparticles Embedded in a Polymeric Matrix as an Effective Sensing Material

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María Elena Martínez-Hernández

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Chem. Proc. 2021, 5(1), 73; https://doi.org/10.3390/CSAC2021-10633 - 07 Jul 2021

Abstract

In this work, an optical fiber sensor based on the localized surface plasmon resonance (LSPR) phenomenon is presented as a powerful tool for the detection of heavy metals (

{Hg}^{2 +}

). The resultant sensing film was fabricated using a nanofabrication process, [...] Read more.

In this work, an optical fiber sensor based on the localized surface plasmon resonance (LSPR) phenomenon is presented as a powerful tool for the detection of heavy metals (

{Hg}^{2 +}

). The resultant sensing film was fabricated using a nanofabrication process, known as layer-by-layer embedding (LbL-E) deposition technique. In this sense, both silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were synthesized using a synthetic chemical protocol as a function of a strict control of three main parameters: polyelectrolyte concentration, loading agent, and reducing agent. The use of metallic nanostructures as sensing materials is of great interest because well-located absorption peaks associated with their LSPR are obtained at 420 nm (AgNPs) and 530 nm (AuNPs). Both plasmonic peaks provide a stable real-time reference that can be extracted from the spectral response of the optical fiber sensor, giving a reliable monitoring of the Hg²⁺ concentration. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessAbstract

Conductive Electrospun Nanofibers for Multifunctional Portable Devices

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Chem. Proc. 2021, 5(1), 37; https://doi.org/10.3390/CSAC2021-10634 - 07 Jul 2021

Abstract

The need to perform in situ sensing measurements lead to the development of innovative and smart field-portable devices. The advantages of such systems are remarkable since they are mainly battery-powered, lightweight and easy to carry and keep. Moreover, field-portable devices are easy to [...] Read more.

The need to perform in situ sensing measurements lead to the development of innovative and smart field-portable devices. The advantages of such systems are remarkable since they are mainly battery-powered, lightweight and easy to carry and keep. Moreover, field-portable devices are easy to use and are able to give fast sensing responses. In the last few years, many efforts have been made in the development of new performing systems and the advantageous use of nanofibrous materials was assessed. To this purpose, the electrospinning has been recognized as the most powerful and facile technique for generating uniform nanofibers with controlled dimension and morphology. When conductive polymers are electrospun, very interesting electrical properties can be obtained along with the well-known ones that are typical of nanofibers. Among these polymers, polyaniline has been extensively used. In this work, an innovative hybrid material based on polyaniline/polyvinyl acetate/graphene oxide nanofibers was developed and tested as a sensor toward the detection of contaminants in aqueous media. Nanofibers, in the form of a compact mat, were deposited onto a support with suitable electrical contacts. Measurements were performed exploiting the excellent electrical properties of the realized nanofibers in both direct and alternating currents. When a direct current was used, the change in the nanofibers’ resistance value was registered upon exposure to contaminated aqueous solutions and used to determine the presence or absence of contaminants, whereas when tests were performed with an alternating current, the quantitative determination of single species in contaminated solutions was also possible. In this way, by integrating the two different measurement methodologies, an opportunely designed multifunctional portable device will be developed for both qualitative and quantitative contaminants determinations. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

Open AccessAbstract

Voltammetric Detection of Mercury Ions at Poly(azulene-EDTA)-like Screen Printed Modified Electrodes

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George-Octavian Buica

, Georgiana-Luiza Tatu (Arnold),

Eleonora-Mihaela Ungureanu

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Gabriela Geanina Vasile

Chem. Proc. 2021, 5(1), 23; https://doi.org/10.3390/CSAC2021-10630 - 07 Jul 2021

Abstract

In recent years, many applications have been developed for the detection of different toxic metals (As, Cd, Cu, Hg, Ni, Pb) in water samples. The classic analytical methods (ICP-MS, AAS with graphite furnace, ICP-EOS with ultrasonic nebulizer) not only require a longer analysis [...] Read more.

In recent years, many applications have been developed for the detection of different toxic metals (As, Cd, Cu, Hg, Ni, Pb) in water samples. The classic analytical methods (ICP-MS, AAS with graphite furnace, ICP-EOS with ultrasonic nebulizer) not only require a longer analysis time (pretreatment of the sample and analysis), but also the costs involved are higher as a result of expensive equipment, costs associated with the method validation process and qualified staff. The use of modified electrodes for trace metals analysi from wastewater samples represents a modern approach which can provide accurate, fast results with selectivity and sensitivity. Thus, here we present the development of the previously obtained glassy carbon-modified electrodes based on poly(2,2′-(ethane-1,2-diylbis(2-(azulen-2-ylamino)-2-oxoethyl)azanediyl))diacetic acid, (polyL) in laboratory-scale studies. In order to analyze Hg(II) ion content from aqueous samples, an assembly system made of carbon screen-printed modified electrodes (SPEs) modified with polyL selective complexing polymeric films coupled with a portable potentiostat was used. The detection of Hg(II) ions was accomplished by chemical accumulation in an open circuit followed by anodic stripping using the differential pulse voltammetry technique. The calibration curve of the analytical method was situated in the range of 20 ppb to 150 ppb (y = 0.0051x + 0.123, R² = 0.9951), with a detection limit of 6 ppb. The precision value for the lower limit of the calibration curve was 20%, while for the upper limit, the value was 10.5%. The novelty of the method consists not only of the low cost of the analysis, but also of the possibility to provide real-time reliable information about the Hg(II) concentration in wastewater using a small and portable device. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

Open AccessProceeding Paper

Study of Gas-Sensing Properties of Titania Nanotubes for Health and Safety Applications

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Vardan Galstyan

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Nicola Poli

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Elisabetta Comini

Chem. Proc. 2021, 5(1), 16; https://doi.org/10.3390/CSAC2021-10625 - 07 Jul 2021

Abstract

We studied the preparation and gas-sensing performance of a hybrid nanomaterial based on titania nanotubes and graphene derivatives. We fabricated the hybrid structure with tunable chemical-sensing properties, achieved by tailoring the structure and composition of graphene oxide and coupling it with titania nanotubes. [...] Read more.

We studied the preparation and gas-sensing performance of a hybrid nanomaterial based on titania nanotubes and graphene derivatives. We fabricated the hybrid structure with tunable chemical-sensing properties, achieved by tailoring the structure and composition of graphene oxide and coupling it with titania nanotubes. The parameters of manufactured sensing structures were investigated for hydrogen and ammonia. Our experimental findings indicate that this research may demonstrate an efficient way to enhance the gas-sensing properties of metal oxide nanomaterials for health and safety applications. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Gold Nanoparticles Functionalized with Mercaptosuccinic Acid as a Means for Detecting Fe(III) Ions

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Nadezhda S. Komova

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Ksenya V. Serebrennikova

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Anna N. Berlina

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Svetlana M. Pridvorova

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Anatoly V. Zherdev

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Boris B. Dzantiev

Chem. Proc. 2021, 5(1), 6; https://doi.org/10.3390/CSAC2021-10624 - 07 Jul 2021

Abstract

The application of mercaptosuccinic acid-capped gold nanoparticles as a sensing probe for the colorimetric detection of Fe(III) is reported. The well-dispersed gold nanoparticles (AuNPs) with a diameter of around 20 nm were obtained by a one-step reaction of tetrachloroauratic acid with mercaptosuccinic acid [...] Read more.

The application of mercaptosuccinic acid-capped gold nanoparticles as a sensing probe for the colorimetric detection of Fe(III) is reported. The well-dispersed gold nanoparticles (AuNPs) with a diameter of around 20 nm were obtained by a one-step reaction of tetrachloroauratic acid with mercaptosuccinic acid (MSA) as a reducing and capping agent, respectively. Fe(III) reportedly causes the aggregation of prepared MSA-capped AuNPs followed by a change in color and a shift to long wavelengths in the absorbance spectra. The resulting method allows for a visual and spectrophotometric Fe(III) determination with detection limits of 30 ng/mL and 23 ng/mL, respectively. MSA-capped AuNPs have been used as sensing probes for the detection of Fe(III) in drinking water samples with a detection limit that is much lower than the maximum permissible level of Fe(III) specified by official regulations (300 ng/mL). Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessAbstract

Carbon Dots as a Fluorescence pH Nanosensor by Application of an Active Surface Preservation Strategy

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Ana Carolina P. Afonso

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Luís Pinto da Silva

Chem. Proc. 2021, 5(1), 2; https://doi.org/10.3390/CSAC2021-10638 - 07 Jul 2021

Abstract

In the environmental, industrial, and biomedical fields, pH monitorization is of the upmost importance. However, the most used type of pH sensors, glass pH-electrodes, still present limitations in their application in low volume samples and in cellular pH sensing, due to their size [...] Read more.

In the environmental, industrial, and biomedical fields, pH monitorization is of the upmost importance. However, the most used type of pH sensors, glass pH-electrodes, still present limitations in their application in low volume samples and in cellular pH sensing, due to their size and invasive nature. Fluorescence-based sensors present a solution to such issues, providing a non-invasive solution to pH sensing. Herein, we report the rational development of carbon dots (CDs) as a pH nanosensor via an active surface preservation (ASP) method. Carbon dots (CDs) are carbon-based fluorescent nanoparticles with valuable properties such as high aqueous solubility, low cost and good biocompatibility, with remarkable fluorescence performance, been increasingly used as fluorescent nanosensors. Namely, these nanomaterials present advantages over molecular probes in terms of (photo)stability and water solubility, among others. By employing ASP strategies, the CDs will be prepared by using precursors with known active functional features. The ASP method allows the nanoparticles to retain the structural features of precursors, thus retaining their properties, without the need for costly and time-consuming post-synthesis functionalization procedures. In this work, we intend to provide a proof-of-concept of this type of strategy by utilizing the known pH-sensitivity of fluorescein to provide a pH-based response to CDs. The resulting CDs presented reversible response by fluorescence enhancement in the range of pH from 4 to 12. The nanoparticles exhibited excellent photostability, in different pH solutions. The studied CDs were also unaffected by, either variation of ionic strength or the presence of interferent species, while being compatible with human cancer cells. Finally, CDs were able to determine the pH of real samples. Thus, a selective pH fluorescent CDs-based nanosensor was developed. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

Open AccessProceeding Paper

Development of Graphene-Doped TiO₂-Nanotube Array-Based MIM-Structured Sensors and Its Application for Methanol Sensing at Room Temperature

by

Teena Gakhar

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Arnab Hazra

Chem. Proc. 2021, 5(1), 74; https://doi.org/10.3390/CSAC2021-10620 - 06 Jul 2021

Abstract

This work concerns the development of a good quality graphene doped TiO₂ nanotube array sensor for efficient detection of methanol. A pure and graphene doped TiO₂ nanotube array was synthesized by electrochemical anodization. Morphological, structural and optical characterizations were performed to [...] Read more.

This work concerns the development of a good quality graphene doped TiO₂ nanotube array sensor for efficient detection of methanol. A pure and graphene doped TiO₂ nanotube array was synthesized by electrochemical anodization. Morphological, structural and optical characterizations were performed to study the samples. Both the nanotube samples were produced in Au/TiO₂ nanotube/Ti type MIM-structured devices. Pure and graphene-doped TiO₂ nanotubes offered a response magnitude of 20% and 28% to 100 ppm of methanol at room temperature, respectively. Response/Recovery time was fast for the graphene doped TiO₂ nanotube array (34 s/40 s) compared to a pure TiO₂ nanotube array (116 s/576 s) at room temperature. This study confirmed the notable enhancement in methanol sensing due to the formation of local heterojunctions between graphene and TiO₂ in the hybrid sample. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Field Nitrogen Dioxide and Ozone Monitoring Using Electrochemical Sensors with Partial Least Squares Regression

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Chem. Proc. 2021, 5(1), 61; https://doi.org/10.3390/CSAC2021-10622 - 06 Jul 2021

Abstract

Low-cost gas sensors detect pollutants gas at the parts-per-billion level and may be installed in small devices to densify air quality monitoring networks for the spread analysis of pollutants around an emissive source. However, these sensors suffer from several issues such as the [...] Read more.

Low-cost gas sensors detect pollutants gas at the parts-per-billion level and may be installed in small devices to densify air quality monitoring networks for the spread analysis of pollutants around an emissive source. However, these sensors suffer from several issues such as the impact of environmental factors and cross-interfering gases. For instance, the ozone (O₃) electrochemical sensor senses nitrogen dioxide (NO₂) and O₃ simultaneously without discrimination. Alphasense proposes the use of a pair of sensors; the first one, NO2-B43F, is equipped with a filter dedicated to measure NO₂. The second one, OX-B431, is sensitive to both NO₂ and O₃. Thus, O₃ concentration can be obtained by subtracting the concentration of NO₂ from the sum of the two concentrations. This technique is not practical and requires calibrating each sensor individually, leading to biased concentration estimation. In this paper, we propose Partial Least Square regression (PLS) to build a calibration model including both sensors’ responses and also temperature and humidity variations. The results obtained from data collected in the field for two months show that PLS regression provides better gas concentration estimation in terms of accuracy than calibrating each sensor individually. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Electrode Modified with Tin(IV) Oxide Nanoparticles and Surfactants as Sensitive Sensor for Hesperidin

by

Elvira Yakupova

and

Guzel Ziyatdinova

Chem. Proc. 2021, 5(1), 54; https://doi.org/10.3390/CSAC2021-10615 - 06 Jul 2021

Abstract

Tin(IV) oxide nanoparticles in combination with surfactants were used as a sensitive layer in a sensor for hesperidin. The effect of the surfactant’s nature and concentration on the hesperidin response was evaluated. The best parameters were registered in the case of 500 µM [...] Read more.

Tin(IV) oxide nanoparticles in combination with surfactants were used as a sensitive layer in a sensor for hesperidin. The effect of the surfactant’s nature and concentration on the hesperidin response was evaluated. The best parameters were registered in the case of 500 µM cetylpyridinium bromide (CPB) as a dispersive agent. The SEM and electrochemical data confirmed the increase in sensor surface effective area and electron transfer rate. The sensor gave a linear response to hesperidin in the ranges of 0.10–10 and 10–75 µM with a detection limit of 77 nM. The approach was successfully tested on orange juices and validated using ultra-HPLC. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Portable Electrochemical Detection of Illicit Drugs in Smuggled Samples: Towards More Secure Borders

by

Marc Parrilla

,

Amorn Slosse

,

Robin Van Echelpoel

,

Noelia Felipe Montiel

,

Filip Van Durme

and

Karolien De Wael

Chem. Proc. 2021, 5(1), 44; https://doi.org/10.3390/CSAC2021-10612 - 06 Jul 2021

Abstract

Illicit drug consumption is posing critical concerns in our society causing health issues, crime-related activities and the disruption of the border trade. The smuggling of illicit drugs urges the development of new tools for rapid on-site identification in cargos. Current methods used by [...] Read more.

Illicit drug consumption is posing critical concerns in our society causing health issues, crime-related activities and the disruption of the border trade. The smuggling of illicit drugs urges the development of new tools for rapid on-site identification in cargos. Current methods used by law enforcement offices rely on presumptive color tests and portable spectroscopic techniques. However, these methods sometimes exhibit inaccurate results due to commonly used cutting agents or because the drugs are smuggled (hidden or mixed) in colored samples. Interestingly, electrochemical sensors can deal with these specific problems. Herein, it is presented an electrochemical device that uses low-cost screen-printed electrodes for the electrochemical detection of illicit drugs by square-wave voltammetry (SWV) profiling. A library of electrochemical profiles is built upon pure and mixtures of illicit drugs with common cutting agents. This library allows the design of a tailor-made script that shows the identification of each drug through a user-friendly interface. Finally, the results obtained from the analysis of different samples from confiscated cargos at an end-user laboratory present a promising alternative to current methods offering low-cost and rapid testing in the field. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Evaluation of Olive Oil Quality Grade Using a Portable Battery-Operated Sensor System

by

Marco Grossi

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Enrico Valli

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Alessandra Bendini

,

Tullia Gallina Toschi

and

Bruno Riccò

Chem. Proc. 2021, 5(1), 40; https://doi.org/10.3390/CSAC2021-10614 - 06 Jul 2021

Abstract

Olive oil quality is normally assessed by chemical analysis as well as sensory analysis to detect the presence of organoleptic defects. Two of the most important parameters that define the quality of olive oil are the free acidity and the peroxide index. These [...] Read more.

Olive oil quality is normally assessed by chemical analysis as well as sensory analysis to detect the presence of organoleptic defects. Two of the most important parameters that define the quality of olive oil are the free acidity and the peroxide index. These chemical parameters are usually determinated by manual titration procedures that must be carried out in a laboratory by trained personnel. In this paper, a portable sensor system to evaluate the quality grade of olive oil is presented. The system is battery operated and characterized by small dimensions, a light weight and quick measurement response. The working principle is based on the measurement of the electrical conductance of an emulsion between a hydro-alcoholic solution and the olive oil sample. Tests have been carried out on a set of 17 olive oil samples. The results have shown how for fresh olive oil samples, the olive oil’s free acidity can be estimated from the electrical conductance of the emulsion. In the case of oxidized olive oil, the measured electrical conductance is also the function of the oxidation level, and a conductance threshold can be set to discriminate between extra virgin olive oils and lower-quality grade oils. The proposed system can be a low-cost alternative to standard laboratory analysis to evaluate the quality grade of olive oil. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Open AccessProceeding Paper

Reproductivity Study of Metal Oxide Gas Sensors Using Two Different Temperature Setups

by

Giulia Zambotti

and

Andrea Ponzoni

Chem. Proc. 2021, 5(1), 26; https://doi.org/10.3390/CSAC2021-10613 - 06 Jul 2021

Abstract

The use of the electronic nose as a screening device is of great interest in various types of applications, including food quality control and environmental monitoring. It is an easy-to-use device and produces a much faster response than that obtained by classical chemical [...] Read more.

The use of the electronic nose as a screening device is of great interest in various types of applications, including food quality control and environmental monitoring. It is an easy-to-use device and produces a much faster response than that obtained by classical chemical and microbiological techniques. The reproductivity of nominally identical electronic noses and sensors is critical. Four identical MOX sensors were compared using two different working methods, namely, the temperature modulation mode and isothermal mode. Each sensor was tested with two standard compounds, water and lactic acid, often identified in food matrices, which are potential applications of the electronic nose. Full article

(This article belongs to the Proceedings of The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry)

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Journal Description

Chemistry Proceedings

Vol. 5

CSAC2021

Vol. 4

Stand Alone Papers 2021

Vol. 3

ECSOC-24

Vol. 2

ECCS 2020

Vol. 1

Stand Alone Papers 2020

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