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2570 KiB

Open AccessArticle

Development of Solid-State Electrochemiluminescence (ECL) Sensor Based on Ru(bpy)₃²⁺-Encapsulated Silica Nanoparticles for the Detection of Biogenic Polyamines

by Anna-Maria Spehar-Délèze, Sallam Almadaghi and Ciara K. O'Sullivan

Chemosensors 2015, 3(2), 178-189; https://doi.org/10.3390/chemosensors3020178 - 21 May 2015

Cited by 17 | Viewed by 5856

Abstract

A solid state electrochemiluminescence (ECL) sensor based on Ru(bpy)₃²⁺-encapsulated silica nanoparticles (RuNP) covalently immobilised on a screen printed carbon electrode has been developed and characterised. RuNPs were synthesised using water-in-oil microemulsion method, amino groups were introduced on their surface, and [...] Read more.

A solid state electrochemiluminescence (ECL) sensor based on Ru(bpy)₃²⁺-encapsulated silica nanoparticles (RuNP) covalently immobilised on a screen printed carbon electrode has been developed and characterised. RuNPs were synthesised using water-in-oil microemulsion method, amino groups were introduced on their surface, and they were characterised by transmission electron microscopy. Aminated RuNPs were covalently immobilised on activate screen-printed carbon electrodes to form a solid state ECL biosensor. The biosensor surfaces were characterised using electrochemistry and scanning electron microscopy, which showed that aminated nanoparticles formed dense 3D layers on the electrode surface thus allowing immobilisation of high amount of Ru(bpy)₃²⁺. The developed sensor was used for ECL detection of biogenic polyamines, namely spermine, spermidine, cadaverine and putrescine. The sensor exhibited high sensitivity and stability. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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345 KiB

Open AccessArticle

Simple and Rapid Determination of Ethanol Content in Beer Using an Amperometric Biosensor

by Vojtěch Polan, Aleš Eisner and Karel Vytřas

Chemosensors 2015, 3(2), 169-177; https://doi.org/10.3390/chemosensors3020169 - 20 May 2015

Cited by 13 | Viewed by 5190

Abstract

An alcohol dehydrogenase-based biosensor was prepared and tested for its use to determine ethanol in beer. The biosensor is based on a screen-printed carbon electrode (SPCE) modified by rhodium dioxide and immobilized with a biocatalytic layer containing the enzyme. Function of the enzyme [...] Read more.

An alcohol dehydrogenase-based biosensor was prepared and tested for its use to determine ethanol in beer. The biosensor is based on a screen-printed carbon electrode (SPCE) modified by rhodium dioxide and immobilized with a biocatalytic layer containing the enzyme. Function of the enzyme biosensor was tested in model ethanol samples, in which it showed a linear range of 15–120 g∙L⁻¹ with a detection limit of 3.3 g∙L⁻¹ (established as 3σ) and response time of 19 s. In a potential window from –0.2 to +0.45 V, interferences of both ascorbic and uric acids were negligible. Several types of marketed beers of Czech provenance were selected and subjected to measurements under optimized conditions but without any pretreatment of real samples. When compared with the reference method (gas chromatography), the results were in quite good agreement for beers of the pale lager type but higher contents of ethanol were indicated in the samples of dark lager beers. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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388 KiB

Open AccessArticle

Pyrolyzed Photoresist Carbon Electrodes for Trace Electroanalysis of Nickel(II)

by Ligia Maria Moretto, Andrea Mardegan, Mattia Cettolin and Paolo Scopece

Chemosensors 2015, 3(2), 157-168; https://doi.org/10.3390/chemosensors3020157 - 15 May 2015

Cited by 6 | Viewed by 5833

Abstract

Novel pyrolyzed photoresist carbon electrodes for electroanalytical applications have been produced by photolithographic technology followed by pyrolysis of the photoresist. A study of the determination of Ni(II) dimethylglyoximate (Ni-DMG) through adsorptive cathodic stripping voltammetry at an in situ bismuth-modified pyrolyzed photoresist electrode (Bi-PPCE) [...] Read more.

Novel pyrolyzed photoresist carbon electrodes for electroanalytical applications have been produced by photolithographic technology followed by pyrolysis of the photoresist. A study of the determination of Ni(II) dimethylglyoximate (Ni-DMG) through adsorptive cathodic stripping voltammetry at an in situ bismuth-modified pyrolyzed photoresist electrode (Bi-PPCE) is reported. The experimental conditions for the deposition of a bismuth film on the PPCE were optimized. The Bi-PPCE allowed the analysis of trace concentrations of Ni(II), even in the presence of Co(II), which is the main interference in this analysis, with cathodic stripping square wave voltammograms characterized by well-separated stripping peaks. The calculated limits of detection (LOD) were 20 ng∙L⁻¹ for Ni(II) alone and 500 ng∙L⁻¹ in the presence of Co(II). The optimized method was finally applied to the analysis of certified spring water (NIST1640a). Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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392 KiB

Open AccessArticle

Arrays of TiO₂ Nanowires as Photoelectrochemical Sensors for Hydrazine Detection

by Michael Ongaro, Michela Signoretto, Valentina Trevisan, Angela Maria Stortini and Paolo Ugo

Chemosensors 2015, 3(2), 146-156; https://doi.org/10.3390/chemosensors3020146 - 14 May 2015

Cited by 17 | Viewed by 5925

Abstract

Electrodes based on arrays of TiO₂ nanowires were prepared by template sol-gel synthesis with the goal of developing a hydrazine photoelectrochemical sensor. Experimental conditions were chosen so that the gelation reaction occurred inside the nanopores of track-etched polycarbonate membranes, with consequent filling [...] Read more.

Electrodes based on arrays of TiO₂ nanowires were prepared by template sol-gel synthesis with the goal of developing a hydrazine photoelectrochemical sensor. Experimental conditions were chosen so that the gelation reaction occurred inside the nanopores of track-etched polycarbonate membranes, with consequent filling with TiO₂nanowires. Different procedures for the removal of the template were examined, in order to obtain arrays of self-standing TiO₂ nanowires. The nanowire arrays were bound to fluorine doped tin oxide substrates to produce handy photoelectrodes. The photocurrent recorded with the photoelectrodes in the presence of hydrazine showed significant dependence on the pollutant concentration. The development of a photoelectrochemical sensor for hydrazine detection in water samples, based on this principle, is presented. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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687 KiB

Open AccessArticle

Automatable Flow System for Paraoxon Detection with an Embedded Screen-Printed Electrode Tailored with Butyrylcholinesterase and Prussian Blue Nanoparticles

by Fabiana Arduini, Daniela Neagu, Viviana Scognamiglio, Sabrina Patarino, Danila Moscone and Giuseppe Palleschi

Chemosensors 2015, 3(2), 129-145; https://doi.org/10.3390/chemosensors3020129 - 28 Apr 2015

Cited by 24 | Viewed by 6599

Abstract

Nowadays extensive volumes of pesticides are employed for agricultural and environmental practices, but they have negative effects on human health. The levels of pesticides are necessarily restricted by international regulatory agencies, thus rapid, cost-effective and in-field analysis of pesticides is an important issue. [...] Read more.

Nowadays extensive volumes of pesticides are employed for agricultural and environmental practices, but they have negative effects on human health. The levels of pesticides are necessarily restricted by international regulatory agencies, thus rapid, cost-effective and in-field analysis of pesticides is an important issue. In the present work, we propose a butyrylcholinesterase (BChE)-based biosensor embedded in a flow system for organophosphorus pesticide detection. The BChE was immobilized by cross-linking on a screen-printed electrode modified with Prussian Blue Nanoparticles. The detection of paraoxon (an organophosphorus pesticide) was carried out evaluating its inhibitory effect on BChE, and quantifying the enzymatic hydrolysis of butyrylthiocholine before and after the exposure of the biosensor to paraoxon, by measuring the thiocholine product at a working voltage of +200 mV. The operating conditions of the flow system were optimized. A flow rate of 0.25 mL/min was exploited for inhibition steps, while a 0.12 mL/min flow rate was used for substrate measurement. A substrate concentration of 5 mM and an incubation time of 10 min allowed a detection limit of 1 ppb of paraoxon (corresponding to 10% inhibition). The stability of the probe in working conditions was investigated for at least eight measurements, and the storage stability was evaluated up to 60 days at room temperature in dry condition. The analytical system was then challenged in drinking, river and lake water samples. Matrix effect was minimized by using a dilution step (1:4 v/v) in flow analysis. This biosensor, embedded in a flow system, showed the possibility to detect paraoxon at ppb level using an automatable and cost-effective bioanalytical system. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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495 KiB

Open AccessArticle

Development of an Electrochemical Sensor for NADH Determination Based on a Caffeic Acid Redox Mediator Supported on Carbon Black

by Chiara Zanardi, Erika Ferrari, Laura Pigani, Fabiana Arduini and Renato Seeber

Chemosensors 2015, 3(2), 118-128; https://doi.org/10.3390/chemosensors3020118 - 13 Apr 2015

Cited by 32 | Viewed by 7873

Abstract

Screen-printed electrode (SPE) modified with carbon black nanoparticles (CB) has been tested as a new platform for the stable deposition of caffeic acid (CFA) on the electrode surface. The electrochemical performance from varying the amount of CFA/CB composite has been tested with respect [...] Read more.

Screen-printed electrode (SPE) modified with carbon black nanoparticles (CB) has been tested as a new platform for the stable deposition of caffeic acid (CFA) on the electrode surface. The electrochemical performance from varying the amount of CFA/CB composite has been tested with respect to NADH determination. The electrocatalytic activity of CFA/CB has also been compared with that of SPEs modified by a single component of the coating, i.e., either CFA or CB. Finally, glycerol dehydrogenase, a typical NADH-dependent enzyme, was deposited on the CFA/CB coating in order to test the applicability of the sensor in glycerol determination. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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601 KiB

Open AccessArticle

Carbon Nanotube-Based Electrochemical Sensor for the Determination of Anthraquinone Hair Dyes in Wastewaters

by Ricardo De Oliveira, Felipe Hudari, Jefferson Franco and Maria Valnice Boldrin Zanoni

Chemosensors 2015, 3(1), 22-35; https://doi.org/10.3390/chemosensors3010022 - 16 Mar 2015

Cited by 14 | Viewed by 8125

Abstract

The present work describes the development of a voltammetric sensor for the selective determination of Acid Green 25 (AG25) hair dye, widely used in commercial temporary hair dyes. The method is based on a glassy carbon electrode modified with multiwalled carbon nanotubes activated [...] Read more.

The present work describes the development of a voltammetric sensor for the selective determination of Acid Green 25 (AG25) hair dye, widely used in commercial temporary hair dyes. The method is based on a glassy carbon electrode modified with multiwalled carbon nanotubes activated in the presence of sulfuric acid, where the anthraquinone group present as a chromophore in the dye molecule is reduced at −0.44 V vs. Ag/AgCl in a reversible process involving two electrons in Britton-Robinson (B-R) buffer solution at pH 4.0. Analytical curves were obtained using square wave voltammetry in the range from 1.0 × 10⁻⁷ to 7.0 × 10⁻⁶ mol·L⁻¹, achieving a detection limit of 2.7 × 10⁻⁹ mol·L⁻¹. The voltammograms recorded for the Acid Black 1 (AB1) dye showed that the azo groups of the dye were reduced on the carbon nanotube-modified electrode (CNTME), presenting a pair of redox peaks at −0.27 V and −0.24 V in the reverse scan. Under these experimental conditions, both dyes could be detected in the water sample, since the AG25 dye is reduced at −0.47 V. The presence of other hair dyes bearing other chromophore groups, such as Acid Black 1, Acid Red 33 and basic blue 99, did not interfere with the method, which showed an average recovery of 96.7 ± 3.5% (n = 5) for AG25 dye determination in the presence of all of these dyes. The method was successfully applied to tap water and wastewater samples collected from a water treatment plant. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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Review

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486 KiB

Open AccessReview

X-Ray Photoelectron Spectroscopic Characterization of Chemically Modified Electrodes Used as Chemical Sensors and Biosensors: A Review

by Elio Desimoni and Barbara Brunetti

Chemosensors 2015, 3(2), 70-117; https://doi.org/10.3390/chemosensors3020070 - 10 Apr 2015

Cited by 134 | Viewed by 11695

Abstract

The characterization of chemically modified sensors and biosensors is commonly performed by cyclic voltammetry and electron microscopies, which allow verifying electrode mechanisms and surface morphologies. Among other techniques, X-ray photoelectron spectroscopy (XPS) plays a unique role in giving access to qualitative, quantitative/semi-quantitative and [...] Read more.

The characterization of chemically modified sensors and biosensors is commonly performed by cyclic voltammetry and electron microscopies, which allow verifying electrode mechanisms and surface morphologies. Among other techniques, X-ray photoelectron spectroscopy (XPS) plays a unique role in giving access to qualitative, quantitative/semi-quantitative and speciation information concerning the sensor surface. Nevertheless, XPS remains rather underused in this field. The aim of this paper is to review selected articles which evidence the useful performances of XPS in characterizing the top surface layers of chemically modified sensors and biosensors. A concise introduction to X-ray Photoelectron Spectroscopy gives to the reader the essential background. The application of XPS for characterizing sensors suitable for food and environmental analysis is highlighted. Full article

(This article belongs to the Special Issue Electrochemical Sensors for Environmental and Food Analysis)

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