Saúl VallejosUniversidad de Burgos | UBU · Department of Chemistry
Saúl Vallejos
Post-Doc
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63
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Introduction
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September 2010 - July 2016
Publications
Publications (63)
Quality control in the food industry is of the upmost importance from the food safety, organoleptic and commercial viewpoints. Accordingly, the development of in situ, rapid, and costless analytical tools is a valuable task in which we are working. Regarding this point, the copper content of grape must has to be determined by wineries along the win...
The initial stages of the pandemic caused by SARS-CoV-2 showed that early detection of the virus in a simple way is the best tool until the development of vaccines. Many different tests are invasive or need the patient to cough up or even drag a sample of mucus from the throat area. Besides, the manufacturing time has proven insufficient in pandemi...
Glucose oxidase (GOX) and catalase (CAT) regulate the amount of H2O2 in honey, by generating or consuming it, so they are related to the antibacterial and antioxidant activity of honey. However, their activities are hardly analysed, since the process requires a previous dialysis that is non-selective, very time-consuming (>24h), eco-unfriendly (>6L...
There is a strong need to reduce food waste while maintaining the quality of packaged food. Thus, we have prepared a new fully organic and metal-free antimicrobial polymer, with the aim of increasing both the shelf life and safety of packaged meat. This antimicrobial polymer is based on widely available commercial acrylic monomers with covalently l...
We report on an innovative method to measure the Zn(II) concentration in pet food commercial pet food samples, both wet and dry food. It is based on a colorimetric sensory polymer prepared from commercial monomers and 0.5% of a synthetic monomer having a quinoline sensory core (N-(8-(2-azidoacetamido)quinolin-5-yl)methacrylamide). We obtained the s...
We have developed an in situ methodology for determining nitrite concentration in processed meats that can also be used by unskilled personnel. It is based on a colorimetric film-shaped sensory polymer that changes its color upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration...
In this work we described the preparation of smart anticounterfeit labels. They are obtained by dipping cellulose paper strips in chromogenic polymer dissolutions. Depending on the selected polymer, up to a maximum of 12 possibilities, the labels can turn into different colors after being soaked with an aqueous solution of NaNO2 and HCl and a NaOH...
We have faced the preparation of fully water-soluble fluorescent peptide substrate with long-term environmental stability (in solution more than 35 weeks) and, accordingly, with stable results in the use of this probe in determining the activity of enzymes. We have achieved this goal by preparing a co-polymer of the commercial N -vinyl-2-pyrrolidon...
Although it is well-known that nitroaromatic compounds quench the fluorescence of different conjugated polymers and form colored Meisenheimer complexes with proper nucleophiles, the potential of paper as a substrate for those macromolecules can be further developed. This work undertakes this task, impregnating paper strips with a fluorene-phenylene...
Plant–pest interactions involve multi-faceted processes encompassing a complex crosstalk of pathways, molecules, and regulators aimed at overcoming defenses developed by each interacting organism. Among plant defensive compounds against phytophagous arthropods, cyanide-derived products are toxic molecules that directly target pest physiology. Here,...
Smart polymers react sharply to small changes in physical or chemical conditions and present an intelligent response to chemical stimuli (i.e., chemical species -including biomolecules-, pH, solvents, redox, stimuli that trigger controlled depolymerization) and physical stimuli (i.e., temperature, light, mechanical stress and electrical stimuli). F...
The synthesis and preparation of 12 chromogenic polymers used to build an intelligent label for security paper applications are described. The process involves coating paper sheets with the polymers. Depending on the number of different polymers used in a combinatory way, a maximum of 12¹² combinations is possible, thus creating a matrix that is pr...
In order to obtain the best physicochemical and the most appealing honey powder as possible, this research assessed three procedures (spray drying, vacuum drying and freeze drying) as well as three carrier agents (Arabic gum, whey protein isolate and maltodextrin) for dehydrating ling-heather honeys (Calluna vulgaris (L.) Hull). Using each carrier...
A new original application for a polyacrylic film based on the monomers 2-(dimethylamino)ethyl methacrylate (NNDA), 2-hydroxyethyl acrylate (2HEA) and methylmethacrylate (MMA) as a starch azure container has been set up for a simple determination of honey diastase activity. The proposed method is based on the correlation of reducing sugars generate...
The healing processes in cutaneous wounds, i.e., chronic wounds, represent a health problem affecting 1-2% of the population. The evaluation of these wounds is mainly based on subjective parameters, although there is a medical consensus on protease activity as the best marker for healing disorders. Here we show the correlation of the amino acid con...
We have developed a new method for the rapid (2 h) and inexpensive (materials cost < 0.02 €/sample) “2-in-1” determination of the total phenolic content (TPC) and the antioxidant activity (AOX) in honey samples. The method is based on hydrophilic colorimetric films with diazonium groups, which react with phenols rendering highly colored azo groups....
We report on the preparation, characterization, and foaming behavior of cellular polymers based on 1-vinyl-2-pyrrolidone (VP) and methyl methacrylate (MMA). Samples with different feed ratios proportions of VP and MMA were prepared following the bulk radical copolymerization procedure, using commercially available monomers and testing two different...
We have developed a new sensory material for the rapid and inexpensive determination of Zn(II), and we have carried out a proof of concept for the determination of Zn(II) in biological samples. The interaction with Zn(II) generates an OFF-ON fluorescence process on the material, which can be recorded both with a fluorimeter and with a smartphone by...
We anchored a colourimetric probe, comprising a complex containing copper (Cu(II)) and a dye, to a polymer matrix obtaining film-shaped chemosensors with induced selectivity toward glycine. This sensory material is exploited in the selectivity detection of glycine in complex mixtures of amino acids mimicking elastin, collagen and epidermis, and als...
We prepare low density nanoporous aramid films reinforced with carbon-based nanocharges (graphene, carbon nanofibers and carbon nanotubes), using ionic liquids to generate and control the porous structure, reaching a density reduction of about 4 times and pore sizes down to 240 nm. Because of the low dispersion ability of the nanocharges in the ara...
The use of Supercritical CO2 (ScCO2) has stablished as a standard technique to produce micro and nanocellular polymers with controlled morphologies and cell sized between 500 nm and several microns. However, overcoming the gap between micro and nanocellular polymers implies the use of long saturation times (up to several days), low temperatures (be...
The use of supercritical CO2 (ScCO2) has been established as a standard technique to produce micro- and nanocellular polymers with controlled morphologies and cell sizes between 500 nm and several microns. However, overcoming the gap between micro and nanocellular polymers implies the use of long saturation times (up to several days) and low temper...
We have prepared high-performance functional aromatic polyamides with sensory pendant groups toward amines. These polymers are colourless. The pendant groups have bromonaphthalimide motifs that react with amines rendering coloured arylamines by nucleophilic aromatic substitution of the halide. Thus, these materials are colorimetric sensors toward a...
We have developed a new method for the rapid and inexpensive determination of the total polyphenol index
(TPI) in wines by simply immersing our sensory film in red or white wines and visually checking the colour
change (qualitative analysis) or by analysing a photo taken of the film with a smartphone (quantitative analysis).
This sensory material i...
Microcellular sensory polymers prepared from solid sensory polymeric films were tested in an aqueous Hg(II) detection process to analyze their sensory behavior. First, solid acrylic-based polymeric films of 100 µm thickness were obtained via radical copolymerization process. Secondly, dithizone sensoring motifs were anchored in a simple five-step r...
We have prepared polymeric films as easy-to-handle sensory materials for the colorimetric detection and quantification of phenol derivatives (phenols) in water. Phenols in water resources result from their presence in pesticides and fungicides, among other goods, and are harmful ecotoxins. Colorless polymeric films with pendant diazonium groups att...
Conventional nonconductive vinylic films with dispersed aniline change their color and become conductive in the presence of specific oxidant gases, namely, chlorine and hydrogen peroxide. The color change arises from the polymerization of the aniline to yield the conjugated polymer polyaniline, which at the same time renders the flexible vinylic fi...
A report on the syntheses, thermal, mechanical and dielectric characterizations of two novel polymeric acrylic materials with azide groups in their pendant structures is presented. Having the same general structure, these polymers differ in length of oxyethylene units in the pendant chain [-CONH-CH2CH2-(O-CH2CH2)nN3], where n is 1 (poly(N-(2-(2-azi...
The preparation of new monodisperse polycrystalline palladium nanoparticles uniformly distributed on the surface of polymers, by simply adding a palladium(II) solution in water to the polymers, is described. The polymer...
A series of cross-linked copolymer films based on 1-vinyl-2-pyrrolidone and methyl methacrylate were produced using different poly(ethylene glycol) dimethacrylates as cross-linking agents. The average molecular mass of the cross-linking agent was varied, then allowing the foaming process using supercritical CO2 (ScCO 2), obtaining mi-crocellular fi...
We have developed a new extremely hydrophilic polymeric film suitable for the detection and quantification of chloride in human sweat directly on the skin. The film, or membrane, has chemically anchored 6-methoxyquinoline groups as chloride responsive fluorescent motifs. We have prepared the sensory material from a standard vinyl copolymer, by a co...
The present review presents the most recent developments concerning the application of sensory polymers in the detection and quantification of different target species. We will firstly describe the main polymers that are being employed as sensory polymers, including, for example, conducting or acrylate-based polymers. In the second part of the revi...
A dense membrane (MS) based on vinyl polymers and containing a pyrylium salt [2,6-diphenyl-4(p-methacryloyloxy)phenylpyryliumtetrafluoroborate] was prepared. The MS has hydrophilic and sensory properties that make it a good material for the selective colorimetric detection of trimethylamine (TMA) vapors, a biogenic amine of great importance in food...
Microcellular polymers have been produced by ScCO2 foaming, based on 1-vinyl-2-pyrrolidone (VP) and butyl-acrylate (BA). Three different copolymers were prepared, varying the compositions of VP and BA, following a simple radical polymerization process using an UV initiator. The samples a good foaming behavior and also excellent flexibility and hand...
We describe herein the direct visual detection of mercury in fish and water using easily prepared polymeric labels. The polymeric film has chemically anchored dithizone motifs. The sensory film is prepared from a conventional vinyl polymer by straightforward solid-phase reactions. The sensory material is stable at ambient conditions, is reusable an...
Green polymers for mercury green analysis: Chemical modification of vinylic polymers to obtain dithizone based materials for the colorimetric detection of mercury in water and fish
We have developed a new fluorogenic polymer capable of detecting the presence of mercury contamination in fish samples. The modified polymer emits blue light when irradiated with UV light proportional to the quantity of mercury, as MeHg⁺ or Hg²⁺, present in fish. The quantitative relation between the concentration of mercury in fish and the increas...
We have developed new functionalized polymers capable to be easily coated by gold nanoparticles, uniformly distributed on the surface of the polymers, by simply adding a gold(III) solution in water to the polymers. The polymer supported gold nanoparticles material was used as an efficient portable and reusable catalyst for Suzuki reactions in mixed...
We synthesized a solid sensory material for the extraction, detection and quantification of iron(III) in aqueous media. The material is a film-shaped colorless polymer membrane that exhibits gel behavior. The Fe(III) extraction and sensing characteristics are imparted by a new monomer derived from a natural product (i.e., Kojic acid), which exhibit...
http://www.unebook.es/es/ebook/avances-en-materiales-polimericos-xiv-reunion-del-grupo-especializado-de-polimeros-gep-de-la-rseq-y-rsef_E0002613013 #####
El libro recopila los últimos avances realizados en ciencia y tecnología de polímeros (plásticos) así como las tendencias y perspectivas en el desarrollo de nuevos materiales poliméricos para apli...
This work describes the preparation of intrinsically blue-colored, high-performance aromatic polyamides (aramids). The color was achieved by preparing a diamine monomer containing a chromogenic azadipyrromethene (ADPM) core, which after polymerizing it with commercially available m-phenyleneisophtahlamide and isophthaloyl chloride gave the blue-col...
We report herein a fluorescence polymer membrane as a film-shaped solid sensory kit for the detection and quantification in water of saccharides, namely, fructose and glucose, and dopamine. The sensory motifs are phenylboronic acids, which are chemically incorporated in the polymer network in the radically initiated bulk polymerization process. The...
Attempts to polymerize trinitrobenzene derivatives (TNB) have been fruitless so far. Accordingly, polymers containing TNB have not been exploited in spite of their envisaged potential applications. Here, we describe two ways for preparing polymers with TNB moieties thus overcoming the previously reported polymerization impairments. We also report o...
Selective and sensitive solid sensory substrates for detecting Al(III) in pure water are reported. The material is a flexible polymer film that can be handled and exhibits gel behavior and membrane performance. The film features a chemically anchored salicylaldehyde benzoylhydrazone derivative as an aluminum ion fluorescence sensor. A novel procedu...
Poly(vinylpyrrolidone-co-butyl acrylate) samples with different proportions of monomers were prepared as tractable and hydrophilic materials. An analysis of the intermolecular interactions between the polymer groups was carried out by FTIR. The dependence of the C-O bands (lactam and pendant butyl ester) with the composition suggests a strong inter...
Poly(vinylpyrrolidone-co-butyl acrylate) samples with different proportions of monomers were prepared as tractable and hydrophilic materials. An analysis of the intermolecular interactions between the polymer groups was carried out by FTIR. The dependence of the C=O bands (lactam and pendant butyl ester) with the composition suggests a strong inter...
A solid substrate comprised of a cross-linked polymer network is shaped as a film with gel-like behaviour and is used to detect aluminium ions in water; concurrently, a water soluble sensory polymer synthesised toward the same purpose is also discussed. The detection in both systems was achieved via fluorescence “turn-on”. The limits of detection f...
Polymer network membranes with a high capacity for water absorption are obtained by radicalpolymerizationofN-[2-(2-hydroxyethoxy)ethyl]methacrylamide(HEEMAM). Ethylene glycol dimethacrylate is used as a crosslinking agent in quantities ranging between 0.05 and 2 mol%. Calorimetric techniques are used to determine the thermal stability of dried memb...
Iron in blood serum, wine and water has been visually detected and quantified quickly by processing photographs of an iron colorimetric sensory polymer substrate. The photographs may be taken with a conventional digital camera or Smartphone. The sensory materials were designed following a straightforward strategy. A proven iron organic chelator was...
TITLE: Study of Some Complexation Reactions in the Design and Synthesis of New Hybrid Polymeric Materials
Colorimetric sensor for Iron in aqueous and biological media, i.e., industrial water, wine and blood / Sensor colorimétrico de hierro en medios acuosos y biológicos, como aguas industriales, vino, y sangre / Autores (por orden): S. Vallejos; M. Trigo; J.L. Pablos; M.A. Muñoz; F.C. García; F. Serna; J.M. García / Entidad titular de derechos: Univers...
The preparation of a fluorogenic sensory material for the detection of biomolecules is described. Strategic functionalisation and copolymerisation of a water insoluble organic sensory molecule with hydrophilic comonomers yielded a crosslinked, water-swellable, easy-to-manipulate solid system for water "dip-in" fluorogenic coenzyme A, cysteine, and...
A fluorogenic sensory film, or dense membrane, capable of detecting Cr(VI), Fe(III), and Hg(II) in water was prepared. The film was prepared by a bulk radical polymerization of different comonomers, one of which contained a piperazinedione motif as sensory fluorophore. The film exhibited gel-like behavior and was highly tractable, even after being...
This paper describes the preparation of a hydrophilic copolymer membrane with two comonomers: 1-vinyl-2-pyrrolidone (commercial) and a new water insoluble piperazinedione derivative, which is a fluorogenic mercury sensing motif. The dense membrane permitted the fluorogenic detection of Hg2+ in aqueous media. The sensitivity of the membrane this cat...
This paper describes a strategy followed to achieve a sensing phenomenon in aqueous media using water-insoluble organic molecules. We have prepared a methacrylamide and a methacrylate with pendant cyanide chemosensors based on a fluorene-derivative motif, and we have fabricated highly hydrophilic membranes by means of copolymerising these hydrophob...
This paper describes a strategy followed to achieve a sensing phenomenon in aqueous media using water-insoluble organic molecules. A sensory polymeric material for the colorimetric sensing of cyanide in water has been developed based on the reactivity of this anion with a fluorene derivative.
Projects
Projects (2)
This project is focused on the design, development and study of new smart organic and hybrid (organic/inorganic) polymer materials. These are high value-added sensory materials for application in advanced technologies related to civil security (detection of explosives and chemical warfare agents), industry (detection of substances of industrial interest), biomedicine (detection and quantification of substances of medical interest), food (smart tag development for the detection of biogenic molecules to inform the consumer of the freshness of the food) and the environment (detection and quantification of cations and anions environmentally harmful). Molecules or substances to be detected (target) will be in the atmosphere, in gaseous phase (explosives, harmful molecules from the point of view of job security, biomolecules generated in the decomposition of food), or in aqueous solution (pollutant molecules, substances of industrial interest regarding their detection, quantification and concentration control).
The developed materials, from the comprehensive synthesis thereof, are dense membranes (films), coatings of commercial commodity and high performance fibers, and integral micro and nanofibers. These are materials with good physical handling from which will be prepared: a) sensory strips or disks (from films); b) clothing with sensory parts to alert to the presence of target substances (labels prepared by coating of commercial fabrics); and c) labels and textiles from fibers obtained by electrospinning.
Regarding the detection of target substances (cations, anions and neutral molecules), the designed sensory materials will behave as selective chromogenic and fluorogenic sensors to these targets. The detection will be in situ and at the time, and preferably through a noticeable change to the naked eye (chromogenic sensor materials). At the same time, fluorogenic sensory materials will also be prepared, which also allow for the in situ detection through irradiation with portable commercial ultraviolet lamps (365nm). The chromogenic probes, through color changes, have the advantage of visual detection and quantification, which can be used by non-specialists, while the fluorogenic are more sensitive, so that somehow they are complementary.
The work includes the design and complete synthesis of functionalised materials: condensation (aromatic copolyamides) and addition of copolymers (acrylate polymers) that incorporate derivatives of azobenzene, kojic acid, TRIS, trinitrobenzene, pyrene, terpyridine, coumarins, or a combination of these, along with the complexes of these with different metals, specifically palladium, platinum, aluminium, iron and lanthanoids.
All the copolymers will be characterized physically and chemically to determine: a) the structure–property relationships that govern the overall behavior of the materials, occasionally with the help of model compounds; and b) their performance as sensors (films, coated textiles and fabrics, and integral micro and nanofibers), both from a chromogenic and fluorogenic viewpoint.