Chemosensors

Research

Jump to: Review

17 pages, 1798 KiB

Open AccessArticle

Absence of Gradients and Nernstian Equilibrium Stripping (AGNES): An Electroanalytical Technique for Chemical Speciation: A Tutorial Review

by Lucía López-Solis, Josep Galceran, Jaume Puy and Encarna Companys

Chemosensors 2022, 10(9), 351; https://doi.org/10.3390/chemosensors10090351 - 25 Aug 2022

Cited by 4 | Viewed by 1813

Abstract

Free metal ion concentrations of amalgamating elements such as Zn, Cd, In, or Pb can be determined with absence of gradients and Nernstian equilibrium stripping(AGNES) in a variety of matrices, ranging from seawater to wine or dissolving nanoparticles. In this hands-on paper, we [...] Read more.

Free metal ion concentrations of amalgamating elements such as Zn, Cd, In, or Pb can be determined with absence of gradients and Nernstian equilibrium stripping(AGNES) in a variety of matrices, ranging from seawater to wine or dissolving nanoparticles. In this hands-on paper, we review the fundamental concepts and provide the practical steps to implement AGNES, including ready-to-run files for the software controlling the potentiostat, computation spreadsheets, step-by-step laboratory protocols, etc. Two case studies with a free Zn concentration determination are discussed: (i) a synthetic solution with the ligand oxalate and (ii) a natural sample of the Segre river (Catalonia, Spain). Suggestions for the extension of AGNES to other systems are indicated. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Figure 1

15 pages, 3243 KiB

Open AccessArticle

Composite Electrodes Based on Carbon Materials Decorated with Hg Nanoparticles for the Simultaneous Detection of Cd(II), Pb(II) and Cu(II)

by Laia L. Fernández, Julio Bastos-Arrieta, Cristina Palet and Mireia Baeza

Chemosensors 2022, 10(4), 148; https://doi.org/10.3390/chemosensors10040148 - 15 Apr 2022

Cited by 6 | Viewed by 2138

Abstract

Monitoring water quality has become a goal to prevent issues related to human health and environmental conditions. In this sense, the concentration of metal ions in water sources is screened, as these are considered persistent contaminants. In this work, we describe the implementation [...] Read more.

Monitoring water quality has become a goal to prevent issues related to human health and environmental conditions. In this sense, the concentration of metal ions in water sources is screened, as these are considered persistent contaminants. In this work, we describe the implementation of customized graphite electrodes decorated with two types of Hg nanoparticles (Hg-NPs), optimized toward the electrochemical detection of Cd, Pb and Cu. Here, we combine Hg, a well-known property to form alloys with other metals, with the nanoscale features of Hg-NPs, resulting in improved electrochemical sensors towards these analytes with a substantial reduction in the used Hg amount. Hg-NPs were synthesized using poly(diallyldimethylammonium) chloride (PDDA) in a combined role as a reducing and stabilizing agent, and then appropriately characterized by means of Transmission Electron Microscopy (TEM) and Zeta Potential. The surface of composite electrodes with optimized graphite content was modified by the drop-casting of the prepared Hg-NPs. The obtained nanocomposite electrodes were morphologically characterized by Scanning Electron Microscopy (SEM), and electrochemically by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The results show that the Hg-NP-modified electrodes present better responses towards Cd(II), Pb(II) and Cu(II) detection in comparison with the bare graphite electrode. Analytical performance of sensors was evaluated by square-wave anodic stripping voltammetry (SWASV), obtaining a linear range of 0.005–0.5 mg·L⁻¹ for Cd²⁺, of 0.028–0.37 mg·L⁻¹ for Pb²⁺ and of 0.057–1.1 mg·L⁻¹ for Cu²⁺. Real samples were analyzed using SWASV, showing good agreement with the recovery values of inductively coupled plasma–mass spectrometry (ICP-MS) measurements. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Graphical abstract

10 pages, 1411 KiB

Open AccessArticle

Potentiometric Determination of Moxifloxacin by Solid-Contact ISEs in Wastewater Effluents

by Sherif A. Abdel-Gawad, Hany H. Arab and Ahmed A. Albassam

Chemosensors 2022, 10(4), 146; https://doi.org/10.3390/chemosensors10040146 - 14 Apr 2022

Cited by 7 | Viewed by 1979

Abstract

In recent years, the use of ion-selective membranes in the sensing and assessment of environmental contaminants has become a critical goal. Using sodium tetraphenylborate (TPB) and phosphotungstic acid (PTA) as ion-pairing agents, two sensitive and selective sensors were manufactured to evaluate the electrochemical [...] Read more.

In recent years, the use of ion-selective membranes in the sensing and assessment of environmental contaminants has become a critical goal. Using sodium tetraphenylborate (TPB) and phosphotungstic acid (PTA) as ion-pairing agents, two sensitive and selective sensors were manufactured to evaluate the electrochemical response of moxifloxacin hydrochloride (MOX). The optimal electrochemical behavior was attained by fine-tuning all assay parameters. The manufactured membranes’ performance was optimal in a pH range from 1.0 to 5.0 with a linearity between 1 × 10⁻⁶ M and 1 × 10⁻² M. The MOX–TPB and MOX–PTA membrane electrodes have Nernstian slopes of 59.2 ± 0.60 mV/decade and 58.4 ± 0.50 mV/decade, respectively. The proposed method was used to determine MOX in its pure form as well as real pharmaceutical wastewater effluents. The fabricated electrodes were effectively applied for the sensitive and selective determination of MOX in actual wastewater effluents without the need for any pre-treatment processes. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Figure 1

13 pages, 1661 KiB

Open AccessArticle

Voltammetric Determination of Active Pharmaceutical Ingredients Using Screen-Printed Electrodes

by Paula Clares, Clara Pérez-Ràfols, Núria Serrano and José Manuel Díaz-Cruz

Chemosensors 2022, 10(3), 95; https://doi.org/10.3390/chemosensors10030095 - 01 Mar 2022

Cited by 6 | Viewed by 3144

Abstract

A simple, fast, sensitive and low-cost voltammetric method using a screen-printed carbon electrode (SPCE) is presented in this work for the simultaneous determination of ascorbic acid (AA), paracetamol (PA), dextromethorphan (DX) and caffeine (CF) in both pharmaceutical formulations and samples of environmental interest. [...] Read more.

A simple, fast, sensitive and low-cost voltammetric method using a screen-printed carbon electrode (SPCE) is presented in this work for the simultaneous determination of ascorbic acid (AA), paracetamol (PA), dextromethorphan (DX) and caffeine (CF) in both pharmaceutical formulations and samples of environmental interest. The oxidative peak current displayed linear dependence on concentration within the range 1.7–60.5, 0.6–40.0, 0.9–8.4 (1st linear part) and 1.8–22.0 mg L⁻¹ for AA, PA, DX and CF, respectively; and detection limits of 0.5, 0.2, 0.3 and 0.5 mg L⁻¹, respectively. The developed differential pulse voltammetric (DPV) method was validated using both a pharmaceutical product and a spiked well water sample. A very good agreement between the determined and the theoretical label drug content and recoveries in the range of 99.5–100.8% were obtained for pharmaceutical product and well water samples, respectively. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Graphical abstract

11 pages, 1593 KiB

Open AccessArticle

Potentiometric Sensors for the Selective Determination of Benzodiazepine Drug Residues in Real Wastewater Effluents

by Sherif A. Abdel-Gawad and Hany H. Arab

Chemosensors 2022, 10(2), 74; https://doi.org/10.3390/chemosensors10020074 - 11 Feb 2022

Cited by 5 | Viewed by 2201

Abstract

The application of ion-selective electrodes (ISEs) in the detection and determination of environmental pollutants has become a very important mission in the last few years. Two selective and sensitive membrane electrodes were fabricated in the laboratory and intended to evaluate the electrochemical response [...] Read more.

The application of ion-selective electrodes (ISEs) in the detection and determination of environmental pollutants has become a very important mission in the last few years. Two selective and sensitive membrane electrodes were fabricated in the laboratory and intended to evaluate the electrochemical response of bromazepam (BRZ) using phosphotungstic acid (PTA) and sodium tetraphenylborate (TPB) as ion pairing agents. The linearity range of the fabricated electrodes was between 1 × 10⁻⁶ M to 1 × 10⁻³ M. Nernstian slopes of 54 mV/decade and 57 mV/decade were obtained for the BRZ-PTA and BRZ-TPB membrane electrodes, respectively. The performance of the fabricated membranes was optimum in the pH range of 3–6. Optimum electrochemical response was attained through the careful adjustment of all assay settings. The cited method was successfully applied for the selective determination of BRZ in either its pure form or real wastewater samples obtained from a pharmaceutical industrial plant. The main core of novelty in the suggested method lies in the application of the membranes for the sensitive, selective, and economic determination of BRZ in real wastewater effluents without the tedious sample pretreatment procedures. This can make the suggested method considered an eco-friendly method, as it minimizes the use of organic solvents and chemicals used in the pretreatment process. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Figure 1

9 pages, 1803 KiB

Open AccessCommunication

“Green” Three-Electrode Sensors Fabricated by Injection-Moulding for On-Site Stripping Voltammetric Determination of Trace In(III) and Tl(I)

by Maria Pitsou, Christos Kokkinos, Anastasios Economou, Peter R. Fielden, Sara J. Baldock and Nickolas J. Goddard

Chemosensors 2021, 9(11), 310; https://doi.org/10.3390/chemosensors9110310 - 03 Nov 2021

Cited by 3 | Viewed by 1595

Abstract

This work reports the fabrication of a new environmentally friendly three-electrode electrochemical sensor suitable for on-site voltammetric determination of two toxic emerging ‘technology-critical elements’ (TCEs), namely indium and thallium. The sensor is fully fabricated by injection-moulding and features three conductive polymer electrodes encased [...] Read more.

This work reports the fabrication of a new environmentally friendly three-electrode electrochemical sensor suitable for on-site voltammetric determination of two toxic emerging ‘technology-critical elements’ (TCEs), namely indium and thallium. The sensor is fully fabricated by injection-moulding and features three conductive polymer electrodes encased in a plastic holder; the reference electrode is further coated with AgCl or AgBr. The sensor is applied to the determination of trace In(III) and Tl(I) by anodic stripping voltammetry using a portable electrochemical set-up featuring a miniature smartphone-based potentiostat and a vibrating device for agitation. For the analysis, the sample containing the target metal ions is spiked with Bi(III) and a bismuth film is electroplated in situ forming an alloy with the accumulated target metals on the working electrode of the sensor; the metals are stripped off by applying a square-wave anodic voltametric scan. Potential interferences in the determination of In(III) and Tl(I) were alleviated by judicious selection of the solution chemistry. Limits of quantification for the target ions were in the low μg L⁻¹ range and the sensors were applied to the analysis of lake water samples spiked with In(III) and Tl(I) with recoveries in the range of 95–103%. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Graphical abstract

10 pages, 1575 KiB

Open AccessArticle

Development of a New Screen-Printed Transducer for the Electrochemical Detection of Thiram

by David Ibáñez, Daniel Izquierdo-Bote, María Begoña González-García, David Hernández-Santos and Pablo Fanjul-Bolado

Chemosensors 2021, 9(11), 303; https://doi.org/10.3390/chemosensors9110303 - 25 Oct 2021

Cited by 9 | Viewed by 2275

Abstract

A new transducer based on a screen-printed carbon electrode has been developed for the quantification of thiram. Detection of this fungicide is based on the performance of two enzymes: (1) aldehyde dehydrogenase catalyzes the aldehyde oxidation using NAD⁺ as a cofactor and [...] Read more.

A new transducer based on a screen-printed carbon electrode has been developed for the quantification of thiram. Detection of this fungicide is based on the performance of two enzymes: (1) aldehyde dehydrogenase catalyzes the aldehyde oxidation using NAD⁺ as a cofactor and simultaneously, (2) diaphorase reoxidizes the NADH formed in the first enzymatic process due to the presence of hexacyanoferrate(III) which is reduced to hexacyanoferrate(II). Taking into account that aldehyde dehydrogenase is inhibited by thiram, the current decreases with pesticide concentration and thiram can be electrochemically quantified below legal limits. The transducer proposed in this work involves the modification of the carbon WE with the co-factors (NAD⁺ and hexacyanoferrate(III)) required in the enzymatic system. The new device employed in this work allows the detection of 0.09 ppm thiram, a concentration below legal limits (Maximum Residue Limits 0.1–10 ppm). Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Graphical abstract

15 pages, 3552 KiB

Open AccessArticle

Dummy Molecularly Imprinted Polymers Using DNP as a Template Molecule for Explosive Sensing and Nitroaromatic Compound Discrimination

by Anna Herrera-Chacon, Andreu Gonzalez-Calabuig and Manel del Valle

Chemosensors 2021, 9(9), 255; https://doi.org/10.3390/chemosensors9090255 - 08 Sep 2021

Cited by 13 | Viewed by 2636

Abstract

This work reports a rapid, simple and low-cost voltammetric sensor based on a dummy molecularly imprinted polymer (MIP) that uses 2,4-dinitrophenol (DNP) as a template for the quantification of 2,4,6-trinitrotoluene (TNT) and DNP, and the identification of related substances. Once the polymer was [...] Read more.

This work reports a rapid, simple and low-cost voltammetric sensor based on a dummy molecularly imprinted polymer (MIP) that uses 2,4-dinitrophenol (DNP) as a template for the quantification of 2,4,6-trinitrotoluene (TNT) and DNP, and the identification of related substances. Once the polymer was synthesised by thermal precipitation polymerisation, it was integrated onto a graphite epoxy composite (GEC) electrode via sol–gel immobilisation. Scanning electron microscopy (SEM) was performed in order to characterise the polymer and the sensor surface. Responses towards DNP and TNT were evaluated, displaying a linear response range of 1.5 to 8.0 µmol L⁻¹ for DNP and 1.3 to 6.5 µmol L⁻¹ for TNT; the estimated limits of detection were 0.59 µmol L⁻¹ and 0.29 µmol L⁻¹, for DNP and TNT, respectively. Chemometric tools, in particular principal component analysis (PCA), demonstrated the possibilities of the MIP-modified electrodes in nitroaromatic and potential interfering species discrimination with multiple potential applications in the environmental field. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Graphical abstract

10 pages, 1895 KiB

Open AccessCommunication

A Novel Multi-Ionophore Approach for Potentiometric Analysis of Lanthanide Mixtures

by Julia Ashina, Vasily Babain, Dmitry Kirsanov and Andrey Legin

Chemosensors 2021, 9(2), 23; https://doi.org/10.3390/chemosensors9020023 - 27 Jan 2021

Cited by 7 | Viewed by 1958

Abstract

This work aims to discuss quantification of rare earth metals in a complex mixture using the novel multi-ionophore approach based on potentiometric sensor arrays. Three compounds previously tested as extracting agents in reprocessing of spent nuclear fuel were applied as ionophores in polyvinyl [...] Read more.

This work aims to discuss quantification of rare earth metals in a complex mixture using the novel multi-ionophore approach based on potentiometric sensor arrays. Three compounds previously tested as extracting agents in reprocessing of spent nuclear fuel were applied as ionophores in polyvinyl chloride (PVC)-plasticized membranes of potentiometric sensors. Seven types of sensors containing these ionophores were prepared and assembled into a sensor array. The multi-ionophore array performance was evaluated in the analysis of Ln³⁺ mixtures and compared to that of conventional monoionophore sensors. It was demonstrated that a multi-ionophore array can yield RMSEP (root mean-squared error of prediction) values not exceeding 0.15 logC for quantification of individual lanthanides in binary mixtures in a concentration range 5 to 3 pLn³⁺. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures

Figure 1

Review

Jump to: Research

20 pages, 8668 KiB

Open AccessReview

Application of Aminopolycarboxylic Complexes of V(IV) in Catalytic Adsorptive Stripping Voltammetry of Germanium

by Agnieszka Królicka, Jerzy Zarębski and Andrzej Bobrowski

Chemosensors 2022, 10(1), 36; https://doi.org/10.3390/chemosensors10010036 - 16 Jan 2022

Cited by 2 | Viewed by 1982

Abstract

In the review, voltammetric analytical procedures that employ vanadium(IV) and aminopolycarboxylic complexes of V(IV) are presented and discussed. The focus of the paper is on the mechanism of vanadium-catalyzed reactions responsible for the amplification of the analytical signal of Ge(IV). The analytical efficacy [...] Read more.

In the review, voltammetric analytical procedures that employ vanadium(IV) and aminopolycarboxylic complexes of V(IV) are presented and discussed. The focus of the paper is on the mechanism of vanadium-catalyzed reactions responsible for the amplification of the analytical signal of Ge(IV). The analytical efficacy of different catalytic systems is compared, and the optimal parameters of the respective procedures are reported. Full article

(This article belongs to the Special Issue Chemical Sensors for the Determination of Persistent and Emerging Contaminants)

► Show Figures