Next Issue
Previous Issue

Table of Contents

Chemosensors, Volume 3, Issue 2 (June 2015), Pages 36-199

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-10
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle Synthesis and Properties of 2'-Deoxyuridine Analogues Bearing Various Azobenzene Derivatives at the C5 Position
Chemosensors 2015, 3(2), 36-54; doi:10.3390/chemosensors3020036
Received: 4 September 2014 / Revised: 7 March 2015 / Accepted: 9 March 2015 / Published: 27 March 2015
Cited by 2 | PDF Full-text (1048 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Nucleic acids that change their properties upon photo-irradiation could be powerful materials for molecular sensing with high spatiotemporal resolution. Recently, we reported a photo-isomeric nucleoside bearing azobenzene at the C5 position of 2'-deoxyuridine (dUAz), whose hybridization ability could be reversibly
[...] Read more.
Nucleic acids that change their properties upon photo-irradiation could be powerful materials for molecular sensing with high spatiotemporal resolution. Recently, we reported a photo-isomeric nucleoside bearing azobenzene at the C5 position of 2'-deoxyuridine (dUAz), whose hybridization ability could be reversibly controlled by the appropriate wavelength of light. In this paper, we synthesized and evaluated dUAz analogues that have various para-substitutions on the azobenzene moiety. Spectroscopic measurements and HPLC analyses revealed that the para-substitutions of the azobenzene moiety strongly affect the photo-isomerization ability and thermal stability of the cis-form. The results suggest that proper substitution of the azobenzene moiety can improve the properties of dUAz as a light-responsive nucleic acid probe. Full article
(This article belongs to the Special Issue Nucleic Acid Probes)
Figures

Open AccessArticle Ascorbic Acid Rejection Characteristics of Modified Platinum Electrodes: A Shelf Life Investigation
Chemosensors 2015, 3(2), 55-69; doi:10.3390/chemosensors3020055
Received: 22 December 2014 / Revised: 21 March 2015 / Accepted: 25 March 2015 / Published: 8 April 2015
Cited by 3 | PDF Full-text (570 KB) | HTML Full-text | XML Full-text
Abstract
Ascorbic acid (AA) is the principle interferent present in brain extracellular fluid that can inhibit the ability of electrochemical sensors to selectively detect a particular analyte of interest. Considerable efforts have been made in recent times to develop highly selective membrane coatings to
[...] Read more.
Ascorbic acid (AA) is the principle interferent present in brain extracellular fluid that can inhibit the ability of electrochemical sensors to selectively detect a particular analyte of interest. Considerable efforts have been made in recent times to develop highly selective membrane coatings to counteract the drawbacks associated with AA interference during in vivo monitoring. The primary objective of the work described within was to investigate the long term effect of storing such selective membranes, i.e., Nafion® and Poly-o-phenylenediamine (PPD) under different conditions and how exposing them to repeated calibration protocols compromises the membranes ability to reject AA. Four different modified platinum (Pt) electrodes, Pt-PPD, Pt-Nafion® (5/2), Pt-Nafion® (1/2)-PPD, and Pt-Nafion® (2/1)-PPD, stored at 4 °C demonstrated deterioration of the polymers integrity when exposed to repeated calibrations. On the contrary, exposing the same four electrode types to single calibrations confirmed excellent retention of AA rejection characteristics. Pt-PPD electrodes were then exposed to varying storage conditions and calibrated against AA on day 1, day 56 and day 168. Storing the Pt-PPD electrodes at 4 °C/N2 saturated glass container demonstrated retention of AA rejection characteristics after day 168. These results have clearly elucidated the optimum storage conditions for Pt-Nafion® and Pt-PPD modified electrodes. Full article
Figures

Open AccessArticle Development of an Electrochemical Sensor for NADH Determination Based on a Caffeic Acid Redox Mediator Supported on Carbon Black
Chemosensors 2015, 3(2), 118-128; doi:10.3390/chemosensors3020118
Received: 27 February 2015 / Revised: 27 March 2015 / Accepted: 1 April 2015 / Published: 13 April 2015
Cited by 8 | PDF Full-text (495 KB) | HTML Full-text | XML Full-text
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)
Figures

Open AccessArticle Automatable Flow System for Paraoxon Detection with an Embedded Screen-Printed Electrode Tailored with Butyrylcholinesterase and Prussian Blue Nanoparticles
Chemosensors 2015, 3(2), 129-145; doi:10.3390/chemosensors3020129
Received: 28 February 2015 / Revised: 15 April 2015 / Accepted: 16 April 2015 / Published: 28 April 2015
Cited by 7 | PDF Full-text (687 KB) | HTML Full-text | XML Full-text
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)
Figures

Open AccessArticle Arrays of TiO2 Nanowires as Photoelectrochemical Sensors for Hydrazine Detection
Chemosensors 2015, 3(2), 146-156; doi:10.3390/chemosensors3020146
Received: 6 February 2015 / Accepted: 5 May 2015 / Published: 14 May 2015
Cited by 4 | PDF Full-text (392 KB) | HTML Full-text | XML Full-text
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 TiO2 nanowires. 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)
Open AccessArticle Pyrolyzed Photoresist Carbon Electrodes for Trace Electroanalysis of Nickel(II)
Chemosensors 2015, 3(2), 157-168; doi:10.3390/chemosensors3020157
Received: 18 March 2015 / Revised: 29 April 2015 / Accepted: 8 May 2015 / Published: 15 May 2015
Cited by 5 | PDF Full-text (388 KB) | HTML Full-text | XML Full-text
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)
Figures

Open AccessArticle Simple and Rapid Determination of Ethanol Content in Beer Using an Amperometric Biosensor
Chemosensors 2015, 3(2), 169-177; doi:10.3390/chemosensors3020169
Received: 21 January 2015 / Accepted: 15 May 2015 / Published: 20 May 2015
PDF Full-text (345 KB) | HTML Full-text | XML Full-text
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)
Open AccessArticle Development of Solid-State Electrochemiluminescence (ECL) Sensor Based on Ru(bpy)32+-Encapsulated Silica Nanoparticles for the Detection of Biogenic Polyamines
Chemosensors 2015, 3(2), 178-189; doi:10.3390/chemosensors3020178
Received: 28 February 2015 / Revised: 12 May 2015 / Accepted: 14 May 2015 / Published: 21 May 2015
Cited by 3 | PDF Full-text (2570 KB) | HTML Full-text | XML Full-text
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)

Review

Jump to: Research

Open AccessReview X-Ray Photoelectron Spectroscopic Characterization of Chemically Modified Electrodes Used as Chemical Sensors and Biosensors: A Review
Chemosensors 2015, 3(2), 70-117; doi:10.3390/chemosensors3020070
Received: 3 December 2014 / Revised: 25 March 2015 / Accepted: 27 March 2015 / Published: 10 April 2015
Cited by 10 | PDF Full-text (486 KB) | HTML Full-text | XML Full-text
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)
Figures

Open AccessReview Application of Photocured Polymer Ion Selective Membranes for Solid-State Chemical Sensors
Chemosensors 2015, 3(2), 190-199; doi:10.3390/chemosensors3020190
Received: 27 March 2015 / Accepted: 22 May 2015 / Published: 2 June 2015
Cited by 2 | PDF Full-text (405 KB) | HTML Full-text | XML Full-text
Abstract
Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized
[...] Read more.
Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized conductive layer and sensitive membrane is presented and the proof of concept is confirmed by two examples of solid-contact electrodes for Ca ions and pH. Full article
(This article belongs to the Special Issue Ionophore-Based Potentiometric Sensors)
Figures

Journal Contact

MDPI AG
Chemosensors Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
E-Mail: 
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Chemosensors Edit a special issue Review for Chemosensors
logo
loading...
Back to Top