Manel del Valle

Autonomous University of Barcelona | UAB · Department of Chemistry

In this work, an electronic tongue (ET) system based on an array of potentiometric ion-selective electrodes (ISEs) for the discrimination of different commercial beer types is presented. The array was formed by 21 ISEs combining both cationic and anionic sensors with others with generic response. For this purpose beer samples were analyzed with the...

This work reports the application of a voltammetric Electronic Tongue (ET) in the analysis of brandies, specifically in their classification according to the scores given by a skilled sensory panel and in the discrimination of different ageing methods. For this purpose, spirits were analyzed with no other pretreatment than their dilution with a sal...

This review presents recent advances concerning work with electronic tongues employing electroanalytical sensors. This new concept in the electroanalysis sensor field entails the use of chemical sensor arrays coupled with chemometric processing tools, as a mean to improve sensors performance. The revision is organized according to the electroanalyt...

This review presents the state of the art of DNA sensors (or genosensors) that utilize electrochemical impedance spectroscopy as the transduction technique. As issue of current interest, it is centered on the use of nanomaterials to develop or to improve performance of these specific biosensors. It will describe the different principles that may be...

This paper reports the use of nanoparticles (NPs)-modified voltammetric sensors for the rapid determination of glycerol in the presence of ethanol and methanol, which are used in the transesterification reaction of biodiesel production. Two different modified electrodes have been prepared to form the electronic tongue (ET): copper hexacyanoferrate...

Electronic tongues (ETs) are multisensor systems based on the coupling of different sensors with high stability and cross-sensitivity towards different species, along with an appropriate chemometric tool that allow the classification of samples and/or the quantification of selected analytes. Despite the great advantages that the data processing sta...

Water quality monitoring has become critical in modern societies in multiple areas and at different stages. In this regard, chemical oxygen demand (COD) has become a key index in water testing, as it readily allows the determination of its overall quality and the presence of organic contaminants. However, conventional COD determination presents sev...

Fluoroquinolones (FQs) are one of the most important types of antibiotics in the clinical, poultry, and aquaculture industries, and their monitoring is required as the abuse has led to severe issues, such as antibiotic residues and antimicrobial resistance. In this study, we report a voltammetric electronic tongue (ET) for the simultaneous determin...

Assessment of water and soil quality is critical for the health, economy and sustainability of any community. The release of a range of life-threatening pollutants from agriculture, industries and the residential communities themselves into the different water resources and soil requires of analytical methods intended for their detection. Given the...

In the present work, the resolution and quantification of mixtures of different opiates compounds in the presence of common cutting agents using an electronic tongue (ET) is evaluated. More specifically, ternary mixtures of heroin, morphine and codeine were resolved in the presence of caffeine and paracetamol. To this aim, an array of three carbon...

The combination of chemometrics and electrochemical sensors modified with molecularly imprinted polymers (MIPs) towards the development of MIP-based electronic tongues (ETs) was explored herein. To demonstrate the potential of such an approach, the simultaneous determination of paracetamol, ascorbic acid and uric acid mixtures in pharmaceutical sam...

This work reports the use of modified screen-printed carbon electrodes (SPCEs) for the identification of three drugs of abuse and two habitual cutting agents, caffeine and paracetamol, combining voltammetric sensing and chemometrics. In order to achieve this goal, codeine, heroin and morphine were subjected to Square Wave Voltammetry (SWV) at pH 7,...

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,...

Graphene and its derivates offer a wide range of possibilities in the electroanalysis field, mainly owing to their biocompatibility, low-cost, and easy tuning. This work reports the development of an enzymatic biosensor using reduced graphene oxide (RGO) as a key nanomaterial for the detection of contaminants of emerging concern (CECs). RGO was obt...

Chemical Oxygen Demand (COD) is a widely used parameter in analyzing and controlling the degree of pollution in water. COD is defined as the amount of molecular oxygen (in milligrams of O2) required to decompose all the organic compounds in 1 L of aqueous solution to carbon dioxide and water. There are many methods reported for COD determination, s...

Biogenic amines (BAs), which are produced naturally due to the decomposition of amino acids, are crucial for the food industry because its formation is directly related to improper storage and the presence of bacteria. High concentrations of BAs can be easily related with the quality and spoilage of the products of this sector. The necessity to qui...

This work attempts the identification of the production year, the cultivar’s region and the aging method used in the elaboration of different Spanish red wines, all from the “tempranillo” grape variety. The identification of such characteristics relies on the use of a voltammetric electronic tongue (ET) system formed by modified graphite-epoxy elec...

This article comments on green aspects of (bio)chemical sensors for qualitative and quantitative analysis applications. First, the aspects that connect chemical sensors and biosensors with the main trends of green analytical chemistry are discussed. To continue, a set of paradigmatic examples of sustainable assays pertaining to the (bio)sensing fie...

Molecularly imprinted polymers (MIPs) are artificially synthesized materials to mimic the molecular recognition process of biological macromolecules such as substrate-enzyme or antigen-antibody. The combination of these biomimetic materials with electrochemical techniques has allowed the development of advanced sensing devices, which significantly...

This manuscript reports the use of nanoparticle-modified voltammetric sensors for the rapid and green determination of chemical oxygen demand in river waters and waters from agricultural waste. Four different variants of modified electrodes have been prepared: CuO nanoparticles electrogenerated over Cu and covered with Nafion film (CuO/Cu-Nf), and...

Herein we investigate the usage of principal component analysis (PCA) and canonical variate analysis (CVA), in combination with the F factor clustering metric, for the a priori tailored selection of the optimal sensor array for a given electronic tongue (ET) application. The former allows us to visually compare the performance of the different sens...

Analytical techniques are employed every day in both, industry and academia. The concept of green analytical chemistry involves making analytical chemistry safer for operators, more sustainable for the environment and more economical. Improvements in the availability of renewable feedstocks, miniaturization, automated technology, and chemical recyc...

Nitrogen and sulphur-doped Carbons Dots (N-CDs and S-CDs) were synthesized by a hydrothermal method and incorporated as surface electrode modifiers to evaluate their properties for electrochemical sensing. The first task was to characterize the synthesized materials, for which different spectroscopies, scanning microscopes, mass spectrometry and el...

The presented manuscript reports the simultaneous detection of a ternary mixture of the benzodiazepines diazepam, lorazepam, and flunitrazepam using an array of voltammetric sensors and the electronic tongue principle. The electrodes used in the array were selected from a set of differently modified graphite epoxy composite electrodes; specifically...

Chemical oxygen demand (COD) is a widely used parameter in analyzing and controlling the degree of pollution in water. Methods of analysis based on electrochemical sensors are increasingly being used for COD quantitation because they could be simple, accurate, sensitive and environmentally friendly. Electro-oxidizing the organic contaminants to com...

In this work, a graphite-epoxy electrode with cyclic voltammetry electrodeposited reduced graphene oxide and nickel oxyhydroxide nanoparticles was prepared by decomposition in NaOH alkaline solution of cyclic voltammetry electrodeposited nickel hexacyanoferrate. FE-SEM studies were performed to confirm the NiOOH nanoparticle; the average size of th...

The presented research focuses on the electrochemical determination of capsaicin, a lipophilic alkaloid which originates hotness in chili peppers. An electrochemical sensor based on epoxy‐graphite composite with the modification of titanium dioxide (TiO2) nanoparticles is developed for the determination of this alkaloid. The measurements were carri...

This manuscript presents a voltammetric biosensing study with use of molecularly imprinted polymers to detect histamine in wine. Polymer beads were synthesized by standard precipitation polymerization method and implemented on the electrode surface via sol-gel immobilization. Scanning and confocal microscopy examinations permitted characterizing th...

Last years have watched the birth and profusion of analytical systems known as “taste sensors” or “electronic tongues”. Regardless of the fancy names, these “taste sensors” and “electronic tongues” are primarily analytical instruments and require responsible handling and application in order to provide for meaningful results. In spite of intensivel...

In the present work, ternary mixtures of Acetaminophen, Ascorbic acid and Uric acid were resolved using the Electronic tongue (ET) principle and Cyclic voltammetry (CV) technique. The screen-printed integrated electrode array having differentiated response for the three oxidizable compounds was formed by Graphite, Prussian blue (PB), Cobalt (II) ph...

Biochar is a charcoal produced from the biomass pyrolysis process that presents a highly porous and functionalized surface. In the present work an array of carbon paste electrodes (CPE) made of different forms of carbon (graphite, carbon nanotubes and activated biochar) was evaluated in the development of an electronic tongue for discrimination and...

Nitrite (NO 2⁻ ) oxidation reactions (NOR) have been performed using a pristine glassy carbon (GC) electrode and Pd modified GC electrode to investigate catalysis and kinetics of oxidation reaction. The XPS analysis revealed that Pd nanoparticles (NPs) on GC is differed electronically from Pd particles alone. Electrochemical observations entailed t...

This work explores an electrode modified with electrochemically reduced graphene oxide (ERGO) for the voltammetric resolution of mixtures of neurotransmitters and its most common interferents. This enhanced sensitivity device coupled with advanced chemometric tools, such as artificial neural networks (ANNs), is able to resolve and quantify complex...

Since graphene discovery on 2004 its use is gaining relevance in sensors field due to its fantastic characteristics using it as transducer material. In the present work it is proposed an array of enzymatic biosensors (laccase and tyrosinase), based on graphene platforms, for the resolution of complex volatile phenolic mixtures. Volatile phenols suc...

This work reports the characterization and application of a voltammetric electronic tongue using an array of glassy carbon electrodes modified with multi‐walled carbon nanotubes containing metal (Pd, Au, Cu) and oxy‐hydroxide nanoparticles (MetalsOOH of Ni, Co) towards the determination of total sugar content in products related with sugarcane‐bioe...

A glassy carbon electrode (GCE) was surface-modified with carbon quantum dots (CQDs) and applied for the effective enhancement of the electrochemical signal for dopamine and uric acid determination. CQDs were obtained from graphite by a green modification of the Hummers method. They were characterized by FTIR-ATR, XPS, solid-state NMR, fluorescence...

This research develops a label-free aptamer biosensor (aptasensor) based on graphite-epoxy composite electrodes (GECs) for the detection of lysozyme protein using Electrochemical Impedance Spectroscopy (EIS) technique. The chosen immobilization technique was based on covalent bonding using carbodiimide chemistry; for this purpose, carboxylic moieti...

This work reports the applicability of a voltammetric sensor array able to quantify the content of 2,4-dinitrophenol, 4-nitrophenol, and picric acid in artificial samples using the electronic tongue (ET) principles. The ET is based on cyclic voltammetry signals, obtained from an array of metal disk electrodes and a graphite epoxy composite electrod...

This chapter describes aptamer biosensors that employ electrochemical impedance signal as transduction principle. With this idea, detection of substances other than nucleic acids through specific conformer folding region interacting with a complementary substance is the starting point to develop these affinity sensors. Substances detected can be io...

This research develops aptasensors for Lysozyme protein detection [...]

Nitrophenols have been widely employed in different applications from explosives to weight loss drugs but the main environmental problem is their generation as degradation products of common herbicides [1,2]. [...]

Trinitrotoluene (TNT) is a widely employed explosive compound; for that reason, an [...]

This chapter presents work with electronic tongues or smart sensors employing electroanalytical sensors and chemometric tools. This new trend in chemical sensing entails the use of arrays of chemical sensors or smart sensors responding with high-dimensionality data, in combination with chemometric data processing tools, as a means to improve the ov...

The proposed approach reports the combined advantages of biosensors made of molecularly imprinted polymers (MIPs) and the modelling capabilities of Artificial Neural Networks (ANN) in a bio-electronic tongue (BioET) analysis system for the very first time. Molecularly imprinted polymers taylor-made for 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG...

This work reports the applicability of a voltammetric sensor array able to evaluate the content of the metabolites of the Brett defect: 4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol in spiked wine samples using the electronic tongue (ET) principles. The ET used cyclic voltammetry signals, obtained from an array of six graphite epoxy modified c...

Dopamine (DA) is an important catecholamine neurotransmitter that plays a relevant role in the human body’s function. Disorders in DA concentrations are related to several neurological diseases such as Parkinson, Alzheimer and schizophrenia. Common physiologic interferences of this neurotransmitter via voltammetric determination are, among others,...

This research develops aptasensors for Lysozyme protein detection [1] using Electrochemical Impedance Spectroscopy (EIS) technique which is a simple, low-cost and rapid high-sensitivity transduction principle to follow biosensing events that takes place at the surface of an electrode; the EIS technique is also capable of showing response at very lo...

This research develops label-free aptasensors for Codeine (Cod) detection using electrochemical impedance Spectroscopy (EIS) technique. EIS is a simple, high-sensitivity, low-cost and rapid transduction principle to follow biosensing events that take place at the surface of an electrode. Besides, the EIS technique is also capable of showing respons...

Volatile phenols such as 4-ethylguaiacol, 4-ethylphenol and 4-ethylcatechol, among others, are natural constituents of wine, which play a role in its aroma. But if their concentration levels are high, volatile phenols can be a defect, deteriorating wine quality. In red wines they act, when at low concentrations, as a distinctive aged character; at...

A novel protocol for use of molecularly imprinted polymer (MIP) in analysis of melamine is presented. Design of polymer for melamine has been achieved using a combination of computational techniques and laboratory trials, the former greatly reducing the duration of the latter. The compatibility and concerted effect of monomers and solvents were als...

In this study, we synthesized graphene oxide (GO) at different oxidation times (30, 60 and 120 minutes) using a modified Hummer’s method and investigated their carbon-to-oxygen (C/O) ratios, the % C–C double bond, the diffraction pattern, their topography and their electrochemical behaviour both by cyclic voltammetry (CV) and electrochemical impeda...

This work reports the application of an electronic tongue as a tool towards the analysis of wine in tasks such as its discrimination based on the maturing in barrels or the prediction of the global scores assigned by a sensory panel. To this aim, red wine samples were first analysed with the voltammetric sensor array, without performing any sample...

In recent years there has been a demand on highly sensitive, selective, and fast-responding analytical methods that, apart from being able to provide a global index of the total phenolic content, may also be able to resolve concentrations of individual species. In this respect, despite the efforts being directed to this field, the separation and qu...

This research develops label free aptasensors for Lysozyme detection using electrochemical impedance Spectroscopy (EIS) technique. EIS [1] is a simple, high-sensitivity, low-cost and rapid transduction principle to follow biosensing events that takes place at the surface of an electrode; the EIS technique is also capable of showing response at very...

This research project develops aptasensors for Lysozyme [1] detection using electrochemical impedance Spectroscopy (EIS) technique. EIS [2] is a simple, high-sensitivity, low-cost and rapid transduction principle to follow biosensing events that takes place at the surface of an electrode; the EIS technique is also capable of showing response at ver...

This chapter presents recent advances concerning work with electronic tongues that employ electrochemical biosensors, that is, bioelectronic tongues. (Bio)electronic tongues represent a new methodological use of (bio)sensors; they start by the use of biosensor arrays and assume the coupling of the obtained complex response with advanced chemometric...

Poster 31

This work reports the application of a voltammetric electronic tongue (ET) towards the simultaneous determination of both nitro-containing and peroxide-based explosive compounds, two families that represent the vast majority of compounds employed either in commercial mixtures or in improvised explosive devices. The multielectrode array was formed b...

A new voltammetric electronic tongue formed with graphite-epoxy composite electrodes which were modified with metal-oxide nanoparticles is presented for the quantification of tryptophan, tyrosine and cysteine aminoacid mixtures. The signals were obtained by cyclic voltammetry, and data was processed using two different chemometric techniques, artif...

This chapter presents recent work with electronic tongues, that is sensor analytical systems formed by an array of chemical sensors featuring low selectivity plus a chemometric tool to process the complex multivariate data that is generated. As the generic application covered is related to security, the described systems are those devised to identi...

An advanced potentiometric electronic tongue and Sequential Injection Analysis (SIA) measurement system was applied for the quantitative analysis of mixtures containing three active pharmaceutical ingredients (APIs): acetaminophen, ascorbic acid and acetylsalicylic acid, in the presence of various amounts of caffeine as interferent. The flow-throug...

In this work, we report a comparative study on three highly specific amplification strategies for the ultrasensitive detection of thrombin with the use of aptamer sandwich protocol. The protocol consisted on the use of a first thrombin aptamer immobilized on the electrode surface, the recognition of thrombin protein, and the reaction with a second...

A detailed overview of arsenic biosensors and advancements is presented with particular emphasis on recombinant whole-cell-based biosensors employing engineered plasmid constructs with the inherent ars operon in cells as the basis of biorecognition. The review discusses the need for the development of rapid, sensitive, and accurate analysis of arse...

A novel application of cellobiose dehydrogenase (CDH) as sensing element for a Bioelectronic Tongue (BioET) system has been tested. In this work CDHs from various fungi, which exhibit different substrate specificities, were used to discriminate between lactose and glucose in presence of the interfering matrix compound Ca(2+) in various mixtures. Th...

A three-sensor array consisting of a graphite-epoxy composite electrode (GEC), 4-carboxybenzo-18-crown-6-GEC and 4-carboxybenzo-15-crown-5-GEC was employed for the simultaneous determination of Cd(II), Pb(II) and Hg(II) by differential pulse anodic stripping voltammetry (DPASV). Sensors were firstly studied for the determination of Hg(II); secondly...

A new VET with five graphite-epoxy composite sensors modified with metal oxide nanoparticles (NPs) is presented for the quantification of tryptophan (TRP), tyrosine (TYR) and cysteine (CYS) mixtures. The signals were obtained by cyclic voltammetry (CV), and data was processed by artificial neural networks (ANNs) (compression with fast Fourier trans...

The research for the development of graphene oxide (GO) based materials have received considerable attention in the field of electroanalytical chemistry, owing both their inherent electronic properties and the presence of reactive oxygenated groups in its surface. Also, electrochemically reduced graphene oxide (ERGO) is very advisable as transducer...