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A humid electronic nose device based on pulse voltammetry has been applied to detect nerve agentsimulants in gas phase. The humid electronic nose consists in a polypropylene piece which containsan array of eight metallic electrodes (i.e., Ir, Rh, Pt, Au Ag, Co, Cu and Ni) divided into two sets of fourworking electrodes housed inside a homemade steel cylinder, and a salt bridge connection to a referenceelectrode. The electrochemical system is fitted to a nylon membrane damped with a background solutionof sodium tetraborate 0.01 M by a second polypropylene piece. The PCA analysis demonstrated that thesystem is able to discern principal organophosphorous nerve agent mimics (DCP, DCNP and DFP) fromorganophosphorous derivatives and some other potential interferents. Besides, the PLS quantificationanalysis showed sound accuracy in the concentration prediction for DCNP in air, good linearity and alimit of detection (LOD) of some a few ppm., Financial support from the Spanish Government (project MAT2012-38429-004) and the Generalitat Valenciana (project PROMETEO/2009/016) is gratefully acknowledged. L.P. is grateful to the Universitat Politecnica de Valencia for her grant.

A comprehensive analysis of the effectiveness of the electrode potential (EV) in tuning the energies of the electronic states (E) of hybrid systems composed by molecules (A) bonded to discrete metal clusters (M) is carried out for the first time by combining experimental SERS data with TDDFT calculations on [Mn-A]q complexes of different sizes (n) and charges (q). It will be demonstrated that the unexplained origin of observed huge energy gains up to G = 5 eV/V involves two different contributions: G = ΔE/ΔEV = SC. The first one is responsible for the effect of a fractional charge (qeff = q/n) on the electronic structure of [Mn-A]q complexes which tunes the CT states through the slopes S of the E vs qeff diagrams. The second contribution (C = Δqeff/ΔEV) is a kind of capacitance that quantifies the ability of the metal to convert the electrode potential EV into the atomic excess of charge qeff. The estimated capacitances of nanometer-size SERS active hot spots are 2 or 3 times larger than those measured fr...

Metallic implants placed in humans exhibit wear and corrosion that result in the liberation of metal-containing by-products. In the case of titanium (Ti) containing implants, the metal containing debris may exist in a number of states, including metallic particles produced by mechanical wear and the products of metal corrosion in biological environments, such as the joints and surrounding fluids and tissues. In addition, these constituents may dissolve in both intracellular and extracellular solutions generating Ti ions. Both species, ions and nanoparticles, show different cellular toxicities. In this work we have evaluated the possible evolution of TiO2 nanoparticles (NPs) into soluble Ti metal ions by contact with biological fluids. For this aim, an in vitro study to address quantitative Ti solubilisation from TiO2 nanoparticles (with a diameter of 21 nm) after incubation with human serum at different concentrations has been conducted. Total Ti determination revealed low solubilisation rates ranging from 0.53 to 0.82% after just one week of incubation in the serum. The incubated serum was then subjected to speciation analysis by anion exchange liquid chromatography using an inductively coupled plasma mass spectrometer (ICP-MS) as an elemental detector for Ti monitoring. The obtained results revealed a significant increase in the Ti signal associated with the fraction of the protein transferrin and preferentially with one of the metal binding sites of the protein, the N-lobe. Thus, the effect of Ti at the cellular level has been evaluated by considering that it can be present either as ions or as nanoparticles using two different cells lines: human enterocytes HT29 and murine osteoblasts MC3T3. Significant toxicity was found at the highest concentration assayed (50 μg mL(-1)) for both Ti species (ions and NPs) and slightly higher for the ionic species at lower concentrations (1 and 10 μg mL(-1)).

Concerns about the bioaccumulation and toxicity of gold nanoparticles inside humans have recently risen. HT-29 and HepG2 cell lines and Wistar rats were exposed to 10, 30 or 60 nm gold nanoparticles to determine their tissue distribution, subcellular location and deleterious effects. Cell viability, ROS production and DNA damage were evaluated in vitro. Lipid peroxidation and protein carbonylation were determined in liver. ICP-MS measurements showed the presence of gold in intestine, kidney, liver, spleen, feces and urine. Subcellular locations of gold nanoparticles were observed in colon cells and liver samples by transmission electron microscopy. Inflammatory markers in liver and biochemical parameters in plasma were measured to assess the inflammatory status and presence of tissue damage. The size of the nanoparticles determined differences in the biodistribution and the excretion route. The smallest nanoparticles showed more deleterious effects, confirmed by their location inside the cell nucleus and the higher DNA damage.

Smell is one of the five human senses. It is fundamental to people and to many living creatures and by extension it is of great importance for the quality control of online production processes in many mass-production industries. G. Dodd and K. Persaud published the first work regarding the artificial sensing of smells and odours and a few years later Gardner defined the technological solution to an electronic nose as: 'an instrument, which comprises an array of electronic chemical sensors with partial specificity and an appropriate patternrecognition system, capable of recognising simple or complex odours.' In agreement with the definition, a competent electronic nose should be capable of working continuously providing useful information of the samples under test and presenting no fatigue over the measurements. Two key elements should be the base of every electronic nose: a sensor array of cross-selective electrodes and a pattern recognition tool to statistically analyze the samples, which has to be able to point out the similarities and dissimilarities among all the measured samples. These statistical methods are known as chemometrics, which combined with sensors arrays has been recognized by many as a method to enhance the results of sensor systems. One of the most classic sensor arrays with which the first electronic noses were built, and that are still in use, is based on metal oxides. However they present some problems and soit has been necessary to investigate and develop new technologies. These will permit the characterisation of gases, vapours and aromas in a fast, economic and, if possible, online manner, in order to generalise the use of electronic noses in many distinct areas and applied technologies. Sensors using semiconducting polymers have been used since the 1970s due to their favourable features. Recently, there have been a number of further developments in the field of organic semiconductors, which suggests that devices based on these may become even more relevant in the near future. This chapter discusses about semiconducting polymers, organic polymers used in gas sensors, their recognition principles and about adsorbent organic conducting polymer composites. Three configurations are used for organic sensors: chemiresistors, transistors (and diodes) and optodes. Some applications in which these sensors are used are also described, such as humidity, ammonia, nitrogen oxide, hydrogen chloride and nitroaromatic explosives.

An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au, Pt, Rh, Ir, Cu, Co, Ag and Ni) encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts, i.e., NH4NO3, MgSO4, NH4Cl, NaCl, Na2CO3, (NH4)2SO4, MgCl2, Na3PO4, K2SO4, K2CO3, CaCl2, NaH2PO4, KCl, NaNO3, K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt, Cu and Ni electrodes. Moreover, PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate.

A comprehensive interpretation of single and multichannel seismic reflection profiles integrated with biostratigraphical data and log information from nearby DSDP and ODP wells has been used to constrain the late Messinian to Quaternary basin evolution of the central part of the Alboran Sea Basin. We found that deformation is heterogeneously distributed in space and time and that three major shortening phases have affected the basin as a result of convergence between the Eurasian and African plates. During the Messinian salinity crisis, significant erosion and local subsidence resulted in the formation of small, isolated, basins with shallow marine and lacustrine sedimentation. The first shortening event occurred during the Early Pliocene (ca. 5.33-4.57 Ma) along the Alboran Ridge. This was followed by a major transgression that widened the basin and was accompanied by increased sediment accumulation rates. The second, and main, phase of shortening on the Alboran Ridge took place during the Late Pliocene (ca. 3.28-2.59 Ma) as a result of thrusting and folding which was accompanied by a change in the Eurasian/African plate convergence vector from NW-SE to WNW-ESE. This phase also caused uplift of the southern basins and right-lateral transtension along the WNW-ENE Yusuf fault zone. Deformation along the Yusuf and Alboran ridges continued during the early Pleistocene (ca. 1.81-1.19 Ma) and appears to continue at the present day together with the active NNE-SSW trending Al-Idrisi strike-slip fault. The Alboran Sea Basin is a region of complex interplay between sediment supply from the surrounding Betic and Rif mountains and tectonics in a zone of transpression between the converging African and European plates. The partitioning of the deformation since the Pliocene, and the resulting subsidence and uplift in the basin was partially controlled by the inherited pre-Messinian basin geometry. © 2013 The Authors. Basin Research © 2013 John Wiley and Sons Ltd, European Association of Geoscientists and Engineers and International Association of Sedimentologists.

[EN] Mesoporous silica microparticles capped with TTF moieties and containing a ruthenium dye in the pores were used for the turn-on optical detection of the nitroaromatic explosives Tetryl and TNT via a selective pore uncapping and release of the entrapped dye., Financial support from the Spanish Government (project MAT2012-38429-C04-01) and the Generalitat Valencia (project PROMETEO/2009/016) is gratefully acknowledged. Y.S. is grateful to the Spanish Ministry of Science and Innovation for her grant. J.O.J. gratefully acknowledge financial support provided by the Villum Foundation and the Danish Natural Science Research Council (#11-106744).

Resumen El priapismo se define como una ereccion prolongada y dolorosa que no tiene por que ser desencadena por un estimulo sexual y que presenta la caracteristica de no modificarse tras la eyaculacion. Se trata de una entidad poco frecuente en edades tempranas y/o adolescentes. En el priapismo de bajo flujo o el venooclusivo o isquemico debe realizarse diagnostico diferencial con causas hematologicas, neoplasias, cuadros infecciosos, ingesta de farmacos, etc., mientras que para el de alto flujo o arterial o no isquemico debemos centrarnos mas en el origen traumatico. El tratamiento del priapismo de bajo flujo constituye una urgencia, ya que debemos evitar un dano irreversible, asi como un dano psicologico que podria derivarse de las consecuencias de una posible disfuncion erectil. Presentamos un caso de priapismo de bajo flujo en un paciente adolescente como inicio de una leucemia mieloide aguda. En la edad pediatrica y en la adolescencia, como hemos dicho, es poco frecuente, aunque debemos estar alerta, ya que puede ser el comienzo de enfermedades graves.

A new electronic tongue to monitor the presence of glyphosate (a non-selective systemic herbicide) has been developed. It is based on pulse voltammetry and consists in an array of three working electrodes (Pt, Co and Cu) encapsulated on a methacrylate cylinder. The electrochemical response of the sensing array was characteristic of the presence of glyphosate in buffered water (phosphate buffer 0.1 mol·dm-3, pH 6.7). Rotating disc electrode (RDE) studies were carried out with Pt, Co and Cu electrodes in water at room temperature and at pH 6.7 using 0.1 mol·dm-3 of phosphate as a buffer. In the presence of glyphosate, the corrosion current of the Cu and Co electrodes increased significantly, probably due to the formation of Cu2+ or Co2+ complexes. The pulse array waveform for the voltammetric tongue was designed by taking into account some of the redox processes observed in the electrochemical studies. The PCA statistical analysis required four dimensions to explain 95% of variance. Moreover, a two-dimensional representation of the two principal components differentiated the water mixtures containing glyphosate. Furthermore, the PLS statistical analyses allowed the creation of a model to correlate the electrochemical response of the electrodes with glyphosate concentrations, even in the presence of potential interferents such as humic acids and Ca2+. The system offers a PLS prediction model for glyphosate detection with values of 098, -2.3 ¿ 10-5 and 0.94 for the slope, the intercept and the regression coefficient, respectively, which is in agreement with the good fit between the predicted and measured concentrations. The results suggest the feasibility of this system to help develop electronic tongues for glyphosate detection. © 2012 by the authors; licensee MDPI, Basel, Switzerland., Financial support from the Spanish Government (Project MAT2009-14564-C04-01 and PCI-Mediterraneo A/024590/09/A/ 03044/10), the Generalitat Valenciana (Project PROMETEO/2009/016), the UPV (project PAID-05-10) and its Centre de Cooperacio al Desenvolupament (Programa ADSIDEO-COOPERACIO 2010) is gratefully acknowledged.

The photodissociation of methyl thionitrite (CH 3 SNO) has been computationally studied by means of CAS-SCF and MS-CASPT2 methods. The analysis of the multiconfigurational wavefunction corroborates the assignments of the absorption spectra, the visible and UV bands assigned to S 0 → S 1 (n, π ∗ ) and S 0 → S 2 (π, π ∗ ) transitions correspond to 1A′ → 1A″(n σ , π ∗ ) and 1A′ → 2A′(n π , π ∗ ) excitations, respectively. With respect to the photochemistry of CH 3 SNO, it is found that the potential energy surfaces associated with the low-lying excited states of this molecule (1 1 A″, 2 1 A′, and 2 1 A″) are repulsive along the NO elimination coordinates. For this reason, population of such excited states leads to NO extrusion as the primary process, in agreement with experiments.

This work presents an approach for multispectral image classification that makes use of a Fuzzy Inference System (FIS). An IKONOS satellite sensor image of a neighborhood in Rio de Janeiro, Brazil has been used. The ground truth used in this work comprises six classes: trees, scrub, buildings, roads, water and shadows. Then, inputs sets, rules and outputs sets were defined. Four input variables, based on four indexes computed from the image spectral bands, have been considered: Normalized Difference Vegetation Index (NDVI), Buildings Index (BI), Water Index (WI) and Road Index (RI). Experimental results show that the proposed method outperforms other methods, achieving higher Overall and Average accuracies, providing a better representation of the classification process.

A family of ferrocene-functionalised receptors of different topologies have been used as receptors for anions. The compounds have been designed to contain both amine nitrogen and ether oxygen atoms and comprises from monoaza to pentaaza derivatives both open-chain (L1, L2, L3) or cyclic (L4, L5) and having from one to five ferrocenyl groups. Solution studies directed to determine the protonation constants of L1, L2 and L3 have been carried out in water (0.1 mol dm3 KNO3, 25 °C) and those of L4 and L5 in 1,4-dioxane-water (70:30 v/v, 0.1 mol dm -3 KNO 3, 25 °C). The protonation behaviour of the receptors can be explained taking into account electrostatic considerations. Speciation studies in the presence of phosphate have been carried out in water for L', L2 and L3 and in dioxane-water for L4 and L5. Speciation studies have also been performed in the presence of ATP with L1, L2 and L3 in water. Selectivity of a mixture of receptors against a certain anion is discussed in terms of ternary diagrams. The shift of the redox potential of the ferrocenyl groups as a function of the pH has been studied. The difference between the oxidation potentials at basic and acidic pH has been determined experimentally and is compared with that theoretically predicted using an electrostatic model previously reported. The electrochemical shift in the presence of ATP and phosphate has been measured in water for L1, L2 and L3 and in the presence of phosphate and sulfate in 1,4-dioxane-water for L4 and L5 as a function of the pH. The electrochemical response found against those anions is quite poor with maximum cathodic shifts off. 30tO mV. The electrochemical response induced by HSO4 and H2PO4- has also been studied in acetonitrile solutions where a large cathodic shift for H 2PO 4- up to ca. 200 mV was found. © The Royal Society of Chemistry 2000.

Potentiometric and electrochemical studies have been carried out with a family of ferrocene redox-functionalised polyamines (L1–L5) and have been directed towards the discrimination, using electrochemical techniques, between the two oxoanions phosphate and sulfate and the electrochemical sensing of ATP. Potentiometric titrations were carried out in THF–water (70∶30 v/v, 0.1 mol dm–3 tetrabutylammonium perchlorate, 25 °C) for L1, L2, L3, L5 and in water (0.1 mol dm–3 potassium nitrate, 25 °C) for L4. Potentiometric data indicate that all receptors studied form stable complexes with sulfate, phosphate and ATP. Distribution for the ternary diagram system sulfate–phosphate–L2 shows pH dependent selectivity patterns; [L2HjSO4]j – 2 species exist at greater than 90% in the pH range 3–4, whereas the corresponding phosphate complexes are the main species in the neutral and basic pH range. The electrochemical studies are in agreement with the speciation results. Sulfate produces in all cyclic receptors maximum cathodic shifts of the redox potential of the ferrocenyl groups around pH 3–4, whereas maximum cathodic shifts for phosphate were found between pH 7 and 8. This behaviour is not observed for the open-chain tetraamine L5. Selective quantitative electrochemical recognition of sulfate and phosphate in the presence of competing anions in aqueous solution has been achieved using the redox-active polyaza ferrocene macrocyclic L2, L3 and L4 receptors. Additionally ATP is able to cathodically shift the oxidation potential of the ferrocenyl groups of L2 and L3 receptors by up to 100 mV. The electrochemical response of L3 against ADP and AMP is also reported.

Summary Introduction We review outcomes after management of meatal balanitis xerotica obliterans (BXO). The primary outcome was recurrent meatal BXO. Methods A database comprising mostly hypospadias patients was queried for meatal BXO. The disease was confirmed histologically in all cases. Management included topical steroids and/or immunosuppressants, and/or surgical excision of BXO with two-stage oral mucosa graft circumferential replacement urethroplasty. Results A total of 12 patients had meatal BXO (8 boys and 4 adults). Of these, 10 had hypospadias, two presenting without prior surgery and eight returning 5–30 years after one or multiple (n = 2) repairs. Another two boys did not have hypospadias: one developing BXO 10 years after newborn circumcision and the other having persistent meatal BXO following therapeutic circumcision. Topical and intraluminal steroids (1% betamethasone or clobetasol) and tacrolimus were used for ≥12 weeks each as primary therapy or for meatal recurrence in a total of six cases. Complete response with resolution of white discoloration and relief of stranguria only occurred in two of the three receiving clobetasol, with follow up ≤12 weeks. BXO excision and urethroplasty was done in 11 patients, 10 using oral mucosa grafts; one with a focal lesion and a negative frozen section had reoperative TIP. Of the 10 undergoing excision with two-stage replacement urethroplasty, six remain disease free at a mean follow-up of 23 months (8–48 months), and four had recurrent stranguria and visible meatal BXO at a median of 26 months (22–105 months). Three of the four with recurrences had additional treatment and one was lost to follow-up. All initially had topical steroids, and two also used tacrolimus, without clinical resolution. These three then underwent a second BXO excision and two-stage oral graft replacement urethroplasty. In two recurrences, BXO was found invading from the meatus proximally within oral mucosa (Figure). Of these three with secondary urethroplasties, two are free of disease at 6 and 18 months, and the third had another meatal recurrence 6 months after the second stage. Discussion We found topical steroids and immunosuppressants to have limited efficacy, with two clinical complete responses achieved only with clobetasol in patients with short follow-up. Forty percent of patients recurred at 2–9 years after visually complete BXO excision and two-stage oral mucosa graft replacement urethroplasty, and in two cases disease invaded into oral mucosa, the first well-documented cases of this occurrence. Download : Download high-res image (175KB) Download : Download full-size image Figure . Recurrent BXO invading the oral mucosa of the neourethra. The appearance after opening the neourethra. The white arrow points to meatal BXO; the black arrow indicates disease extending from the meatus proximally within the oral mucosa of the neourethra.

In order to monitor the chloride penetration processes, a potentiometric embedded thick-film sensor was developed. This paper includes the results of research on the characterization of Cl− sensors made of Ag/AgCl resistive pastes (materials, sensitivity and detection limit, reproducibility, reversibility and response time, long-term performance and reliability in the presence of interfering agents). Theoretical expressions have been developed to describe the potentiometric response including the presence of OH− and bromide ions. The study shows that thick-film sensors are able to monitor Cl− activity as a function of the redox potential. Sensors are also capable of providing reliable and continuous real-time information on phenomena related to the progress of the chloride penetration front in concrete specimens. These sensors are a promising tool because thick-film technology allows us to obtain miniaturized, low-cost, robust and stable long-term sensors for Cl− monitoring., The pre-doctoral scholarship granted to Roman Bataller Prats within the program "Formacion de Personal Investigador (FPI) 2012" from Universitat Politecnica de Valencia is gratefully acknowledged.

The analysis of photoinduced charge transfer (CT) processes in a particular SERS spectrum is not a trivial task since each system must be studied separately and no universal selection rules can be proposed for this kind of enhancement mechanism. Despite this, we found out in previous studies that the SERS-CT spectra of benzene-like molecules are mainly characterized by the strong enhancement of the totally symmetric 8a ring-stretching vibration and we have used this as a propensity rule to recognize the presence of resonant CT processes in the SERS of these adsorbates. However, it is necessary to cautiously consider the relevant symmetry of the system under study before applying this simplified rule. When the molecule shows a low symmetry (or the relevant symmetry is reduced by the adsorption on the metal as it was demonstrated in the case of pyrimidine), the selective intensification of the 8a mode can be disguised by the redistribution of the CT enhancement with another close vibration in wavenumber, na...

[EN] The synthesis of capped mesoporous silica nanoparticles (MSN) conjugated with an antibody (AB) as a gatekeeper has been carried out in order to obtain a delivery system able to release an entrapped cargo (dye) in the presence of a target molecule (antigen) to which the conjugated antibody binds selectively. In particular, MSN loaded with rhodamine B and functionalized on the external surface with a suitable derivative of N-(t-butyl)- 3-oxo-(5a,17b)-4-aza-androst-1-ene-17-carboxamide (finasteride) have been prepared (S1). The addition of polyclonal antibodies against finasteride induced capping of the pores due to the interaction with the anchored hapten-like finasteride derivative to give a MSN¿hapten¿AB nanoparticle S1-AB. It was found that the addition of capped material S1-AB to water solutions containing finasteride resulted in displacement of the antibody, pore uncapping and entrapped-dye release. The response of the gated material is highly selective, and only finasteride, among other steroids, was able to induce a significant uncapping process. Compared with finasteride, the finasteride metabolite was able to release 17% of the dye, whereas the exogen steroids testosterone, metenolone and 16-b-hydroxystanozolol only induced very little release of rhodamine B (lower than 10%) from aqueous suspensions containing sensing solid S1-AB. A detection limit as low as 20 ppb was found for the fluorimetric detection of finasteride. In order to evaluate a possible application of the material for label-free detection of finasteride, the capped material was isolated and stored to give final sensing solid S1-AB-i. It was found to display a similar behavior towards finasteride as to that shown by freshly prepared S1-AB; even after a period of two months, no significant loss of selectivity or sensitivity was noted. Moreover, to study the application for the detection of finasteride in biological samples, this ¿aged¿ material, S1-AB-i, was tested using commercially available blank urine as matrix. Samples containing 70 and 90% blank urine were spiked with a defined amount of finasteride, and the concentration was determined using capped S1-AB-i. Recovery ranges from 94% to 118% were reached., Financial support from the Spanish Government (project MAT2009-14564-C04-01) and the Generalitat Valenciana (Spain) (projects PROMETEO/2009/016 and PROMETEO/2010/008) is gratefully acknowledged. E. C. thanks the Minesterio de Ciencia e Innovacion (MICINN, Spain) for her fellowship.

Electronic equipment (IDM-1) especially designed for the application of voltammetric and impedometric electronic tongues is described. For impedance spectroscopy the equipment permits the generation of sinusoidal signals with a frequency in the range of 1 Hz to 1 MHz and programmable amplitude up to 1 Vpp. For voltammetry the IDM-1 equipment generates a sequence of up to 32 pulses with an amplitude that can be configured for each of the pulses in the range [-0.5; +0.5 V]. Voltammetric studies were performed using a total of eight working electrodes (i.e. Au, Pt, Ir, Rh, Ag, Cu, Ni, and Co) which were housed in a stainless steel cylinder used at the same time as both the body of the electronic tongue system and the counter/reference electrode. The width of the pulses can also be configured with a maximum value of 40 ms. The system consists of a software application that runs on a PC and electronic equipment. In order to test the capabilities of the designed system, impedometric and voltammetric measurements were carried out on five different commercial cola drinks (brands I-V). Three different waveforms were used in the voltammetric study (i.e. staircase, ascendant SAPV and descendant SAPV). The voltammetric response and the impedance phase and module values obtained were processed using PCA. A remarkable discrimination between all cola drinks was seen using the descendant waveform and a group of metal electrodes (Ni, Co, Cu, Ag). In contrast, impedance spectroscopy technique discriminated one brand (brand I) from the others. © 2012 Elsevier Ltd. All rights reserved., We thank MICINN (MAT2009-14564-C04-02) for a research fellowship.

This paper proposes a reasonable methodology for the design of pulse arrays applied in classification and quantification techniques based on the use of pulse voltammetric electronic tongues. As model problem we designed a procedure to predict levels of ferrocene, TCNQ and Ru(bipy)(3)(2+) using a voltammetric electronic tongue employing a set of noble electrodes; i.e. Au, Pt, Ir and Rh. Ferrocene, TCNQ and Ru(bipy)(3)(2+) have been selected as model compounds because these are molecules with well-defined redox processes. The electrodes were housed inside a stainless steel cylinder which was used as the body of the electronic tongue system. A SCE was used as reference electrode. An electrochemical study of the response of ferrocene TCNQ and Ru(bipy)(3)(2+) was carried out as a first step with the aim of characterise the redox processes in these compounds. Different samples containing ferrocene,TCNQ and Ru(bipy)(3)(2+) were prepared following an experimental design in which a system of three compounds/three levels was established. Multivariate analysis based on Partial Least Square (PLS) techniques was applied for data management and prediction models building. Several set of pulses were tested and a general procedure to their design for their use in voltammetric electronic tongues is discussed and proposed. (C) 2011 Elsevier B.V. All rights reserved., We thank the Spanish Government (projects MAT2009-14564-C04-01), Generalitat Valenciana (project PROMETEO/2009/016) for support. PCI-Mediterraneo A/024590/09/A/03044/10) and the UPV (project PAID-05-10) are gratefully acknowledged.

We report herein the use of a combined system for the analysis of the spoilage of wine when in contact with air. The system consists of a potentiometric electronic tongue and a humid electronic nose. The potentiometric electronic tongue was built with thick-film serigraphic techniques using commercially available resistances and conductors for hybrid electronic circuits; i.e. Ag, Au, Cu, Ru, AgCl, and C. The humid electronic nose was designed in order to detect vapours that emanate from the wine and are apprehended by a moist environment. The humid nose was constructed using a piece of thin cloth sewn, damped with distilled water, forming five hollows of the right size to introduce the electrodes. In this particular case four electrodes were used for the humid electronic nose: a glass electrode, aluminium (Al), graphite and platinum (Pt) wires and an Ag-AgCl reference electrode. The humid electronic nose together with the potentiometric electronic tongue were used for the evaluation of the evolution in the course of time of wine samples. Additionally to the analysis performed by the tongue and nose, the spoilage of the wines was followed via a simple determination of the titratable (total) acidity. © 2011 Elsevier B.V., We thank the Spanish Government (project MAT2009-14564-C04) and the Generalitat Valenciana (project PROME-TEO/2009/016) for support. Luis Gil-Sanchez also thanks the Universidad Politecnica de Valencia for support (Primeros Proyectos de Investigacion - PAID-06-09) and the Generalitat Valenciana (proyectos de I+D para grupos de investigacion emergentes - 2009/8650).

[EN] Trapped: Mesoporous silica nanoparticles were loaded with a fluorescent guest and functionalized with octadecyltrimethoxysilane. The alkyl chains interact with paraffins, which build a hydrophobic layer around the particle (see picture). Upon melting of the paraffin, the guest molecule is released, as demonstrated in cells for the guest doxorubicin. The release temperature can be tuned by choosing an appropriate paraffin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., Financial support from the Spanish Government (projects MAT2009-14564-C04-01 and SAF2010-15512) and the Generalitat Valenciana (projects PROMETEO/2009/016 and PROMETEO/2010/005) is gratefully acknowledged. L.M. thanks the Generalitat Valenciana for a VALi+d postdoctoral contract. We thank UPV electron microscopy and CIPF confocal microscopy services for technical support.

A method for predicting levels of sodium chloride, sodium nitrite and potassium nitrate in minced meat by using a combination of two different electrochemical methods; namely an electronic tongue (ET) based on pulse voltammetry and electrochemical impedance spectroscopy measurements is proposed here. The measurements with the voltammetric ET were carried out on both saline solutions (brines) and minced meat, whereas the impedimetric sensor was used only in minced meat. The addition of the salts was performed following an experimental design in which a system of three compounds/three levels was established. Multivariate analysis including Cross validation and Partial Least Square (PLS) techniques were applied for data management and prediction models building. A very good prediction of the concentration of chloride was achieved, whereas the prediction for the concentration of nitrate and nitrite can be considered as moderate.

The molecular mechanism of the reaction of nitroglycerin with a cysteil-cysteine derivative has been studied by quantum mechanical methods; in particular, density functional theory with the accurate meta exchange-correlation functional M06-2X was used. The first reaction step is nitration of a deprotonated cysteine of the dipeptide. Afterward, six reaction steps are followed to yield the final products of the process: 1,2-glyceryl dinitrate (GDN), nitric oxide (NO), peroxynitrite anion (−OONO), and superoxide anion (O2 −) plus an intramolecular disulfide bond in the dipeptide. Two nitroglycerin molecules are decomposed for each disulfide bond formation in the dipeptide. A reducing agent is necessary to complete the global reaction. The action of the reductant triggers S-peroxynitrite formation, which, in turn, can decompose into −OONO or NO plus O2 −.

A method for predicting levels of chloride, nitrite and nitrate in minced meat by using an electronic tongue based on pulse voltammetry is proposed here. The electronic tongue consists of a set of noble (Au, Pt, Rh, Ir, Ag) and non-noble (Ni, Co, Cu) electrodes that were housed inside a stainless steel cylinder used at the same time as both the body of the electronic tongue system and the counter/reference electrode. An electrochemical study of the response of the anions Cl − , NO 3 − and NO 2 − using the different noble and non-noble electrodes was carried out in water in order to design a set of pulses for the electronic tongue. The determination of the concentration of chloride, nitrate and nitrite with the voltammetric tongue was carried out on both saline solutions (brines) and minced meat. The addition of the salts was performed following an experimental design in which a system of three compounds/three levels was established. Multivariate analysis including cross validation and partial least square (PLS) techniques were applied for data management and prediction models building. A very good prediction of the concentration of the anions chloride, nitrate and nitrite was achieved in brines. In minced meat, PLS models showed reduction in the prediction capabilities caused by a matrix effect, nevertheless the system still shows good accuracy and precision in the determination of concentration levels of these anions.

We report the preparation of a MCM-41 mesoporous material that contains the dye [Ru(bipy) 3 ]Cl 2 (bipy= bipyridine) inside the mesopores and functionalised with suitable binding groups at the entrance of the pores. Solids S1―S3 were obtained by the reaction of the mesoporous material with N-methyl-N'-propyltrimethoxysilylimidazolium chloride, N-phenyl-N'-[3-(trimethoxysilyl)propyl]thiourea, or N-phenyl-N'-[3-(trimethoxysilyl)propy1]urea, respectively. A study of the dye delivery of these systems in buffered water (pH 7.0, 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES), 10 ―3 mol dm ―3 ) in the presence of a family of carboxylate ions was carried out. In the interaction of the anions with the surface of the solids, the response depends on the characteristics of the binding groups (i.e., imidazolium, urea and thiourea) at the pore outlets and their specific interaction with the corresponding anion. The interaction of long-chain carboxylate ions with the binding sites at the surface of the solids resulted in a remarkable inhibition of the delivery of the dye. This inhibition was observed clearly for the dodecanoate anion, whereas the octanoate, decanoate, cholate, deoxycholate, glycodeoxycholate and taurocholate anions induced a certain pore blockage that varied according to the solid studied. The interaction of smaller anions, such as acetate, butanoate, hexanoate and octanoate, with the solids had no effect on the dye release process. The possible use of the gating system for the chromo-fluorogenic detection of anionic surfactants through selective dye delivery inhibition was also explored. Molecular dynamic simulations that use force-field methods have been made to theoretically study the capping carboxylate mechanism. The calculations are in agreement with the experimental results, thus allowing a representation of the dye delivery inhibition in the presence of long-chain carboxylate ions.

Chemical warfare (CW) agents are toxic chemicals that have been used in several terrorist attacks in recent years. Among CW species, nerve agents are probably the most dangerous; their high toxicity and facile synthesis underscores the need to detect these lethal compounds with quick, reliable procedures. Analytical methods based on enzymatic assays and physical measurements have generally been used to detect these hazards. However, these protocols usually have limitations such as low selectivity, poor portability, and a certain level of complexity. In recent years, several chromogenic and fluorogenic sensors, and reagents for the detection of nerve agents have been described. For instance, approaches that involve perborate-mediated oxidation of organophosphorus agents, fluorescent probes based on polyethylene terephthalate (PET), assays that use oximate-containing derivatives, molecularly imprinted polymers, nanoparticles, carbon nanotubes, porous silicon, displacement-like procedures, and cyclization reactions in push–pull chromophores have been reported. Most of these protocols rely on changes in fluorescence properties, whereas few examples deal with color modulations. Colorimetric detection is particularly appealing because it uses low-cost, widely available instrumentation and allows assays to be detected with the naked eye. However, the development of selective, sensitive chromogenic probes for the detection of deadly chemical species is still rare. Given our interest in the design of novel hybrid organic– inorganic materials as probes, we focused on the preparation of a new optical test for the detection of nerve agent mimics based on nerve agent control of mass transport to the surface of functionalized silica nanoparticles. The chromogenic approach (Scheme 1) involves the use of silica nanoparticles that are functionalized with two different subunits— thiol groups (SH) and aliphatic alcohols (OH). The role of the

Fluvial piracy in the Guadix-Baza basin (southeast Spain) promoted erosion of a high volume of sediments during the late Quaternary, after the former internal drainage of this basin changed to external due to headward erosion by the Guadalquivir River. As a response to load release, this basin underwent uplift, which, in turn, enhanced fluvial incision and erosional processes. Differential erosion within the Guadix-Baza basin resulted in dissimilar isostatic rebound. We numerically model the lithospheric response to sediment unloading and show a total rising of 15 m in the Guadix subbasin compared to 2 m in the Baza subbasin. This differential uplift is likely to have been accommodated along the Baza normal fault, which has been active throughout the Quaternary. Modeling results suggest that ∼13% of the total Quaternary fault throw directly arises from the differential isostatic readjustment between subbasins. This example is one of the first estimates of fault slip partitioning between tectonic and isostatic effects due to unloading driven by river incision.

The seafloor of the Alboran Sea in the western Mediterranean is disrupted by deformations resulting from convergence between the African and Eurasian plates. Based on a compilation of existing and new multibeam bathymetry data and high-resolution seismic profiles, our main objective was to characterize the most recent structures in the central sector, which depicts an abrupt morphology and was chosen to investigate how active tectonic processes are shaping the seafloor. The Alboran Ridge is the most prominent feature in the Alboran Sea (>130 km in length), and a key element in the Gibraltar Arc System. Recent uplift and deformation in this ridge have been caused by sub-vertical, strike-slip and reverse faults with associated folding in the most recent sediments, their trend shifting progressively from SW–NE to WNW–ESE towards the Yusuf Lineament. Present-day transtensive deformation induces faulting and subsidence in the Yusuf pull-apart basin. The Alboran Ridge and Yusuf fault zones are connected, and both constitute a wide zone of deformation reaching tens of kilometres in width and showing a complex geometry, including different active fault segments and in-relay folds. These findings demonstrate that Recent deformation is more heterogeneously distributed than commonly considered. A narrow SSW–NNE zone with folding and reverse faulting cuts across the western end of the Alboran Ridge and concentrates most of the upper crustal seismicity in the region. This zone of deformation defines a seismogenic, left-lateral fault zone connected to the south with the Al Hoceima seismic swarm, and representing a potential seismic hazard. Newly detected buried and active submarine slides along the Alboran Ridge and the Yusuf Lineament are clear signs of submarine slope instability in this seismically active region.

Surface-enhanced Raman scattering (SERS) of benzoate recorded on silver electrode have been analyzed on the basis of a charge transfer (CT) enhancement mechanism similar to a resonance Raman (RR) process where a photoinduced electron transfer between a metal and an adsorbate takes place. Given that benzoic acid (BzH) is adsorbed on silver as benzoate anion (Bz−), this resonant CT process implies the transient formation of the corresponding radical dianion (Bz•2−). The dependence of the relative SERS intensities on the electrode potential has been analyzed on the basis of ab initio calculations of the electronic properties of the isolated adsorbate in its ground and excited CT states (Bz − and Bz•2−, respectively). Moreover, configuration interaction singles (CIS) calculations have also been carried out for the Ag2−benzoate (Ag2−Bz−) supermolecule, which shows two excited singlets, namely CT0;1B1 and CT1;1A2, where the properties of the adsorbate are quite similar to those of the radical dianion of the iso...

The measurement of salt content in processed products still remains a problem to solve in the food industry due to the destructive nature of the conventional measurement methods. In this paper a method to assess salt content in food products such as cured ham or pork loin using impedance spectroscopy is presented. A low-cost system to carry out a punctual measurement of the impedance inside the food sample based on a non-destructive sensor was developed. The system includes an electronic equipment that allows the implementation of impedance spectroscopy and an electrode consisting of a coaxial needle. In order to validate the equipment, solutions with different salt concentrations were measured. The impedance modulus and phase values obtained for each frequency were processed using PLS; the results show a very good correlation between predicted and observed data. The same process was carried out on minced meat samples and again a good correlation was obtained. The PLS tool generated a model that permits prediction of salt levels in new meat samples.

A novel two-step protocol for the colorimetric detection of ionic surfactants was developed using simple silica supports functionalised with suitable binding groups. Solid S1 was synthesised by reaction of silica with N-methyl-N′-propyltrimethoxysilylimidazolium chloride to obtain a final solid containing imidazolium coordinating moieties. In the first step, solid S1 in contact with anionic surfactant solutions provides the superficial self-assembly organization of the surfactants on the cationic functionalised surface. This layer would be remarkably hydrophobic with the long alkyl chains most likely pointing toward the bulk solution, which in the second step is able to extract a suitable dye (Methylene Blue) from water. The detection principle depends on the fact that the self-assembly process of the anionic surfactant is selective as a consequence of unique strong hydrophobic interactions between surfactant molecules in the monolayer formed. The final behaviour signalling the presence of anionic surfactants would be depletion of the dye solution and coloration of the solid, both visible to the naked eye. A similar protocol was used for the detection of cationic surfactants. In this case solid S2 was prepared containing sulfonate groups. S2 was obtained by reaction of silica with 3-mercaptopropyltriethoxysilane (MPTS) following the oxidation of the mercapto group to sulfonate by adding H2O2. In this case the interaction of cationic surfactants with the S2 surface results in the self-assembly of the cationic surfactants on the anionic surface. In the second step, the addition of a suitable anionic dye (i.e. Patent Blue) then leads to the signalling of the presence of cationic surfactants. S1 and S2 solids were characterised using standard solid-state techniques. A study of the response of these solids was carried out on different concentrations of anionic, cationic and neutral surfactants and in the presence of compulsory water-present anions and cations. The partial decolouration of the dye solution or the corresponding colouration of the solid was related to the concentration of the surfactants in the aqueous solution. The method comprises a novel organic-solvent-free approach for the colorimetric detection of anionic or cationic surfactants. A model was also developed able to interpret the colorimetric behaviour of the solids based on (i) surfactant adsorption on the charged surface and (ii) further extraction of the corresponding dye.

This paper describes the design of new controlled delivery systems consisting of a mesoporous support functionalized on the pore outlets with a certain hapten able to interact with an antibody that acts as a nanoscopic cap. The opening protocol and delivery of the entrapped guest is related by a displacement reaction involving the presence in the solution of the antigen to which the antibody is selective. As a proof-of-the-concept, the solid MCM-41 was selected as support and was loaded with the dye [Ru(bipy)(3)]Cl(2). Then a suitable derivative of the hapten 4-(4-aminobenzenesulfonylamino)benzoic acid was anchored on the outer surface of the mesoporous support (solid S1). Finally the pores were capped with a polyclonal antibody for sulfathiazole (solid S1-AB). Delivery of the dye in the presence of a family of sulfonamides was studied in phosphate-buffered saline (PBS; pH 7.5). A selective uncapping of the pores and dye delivery was observed for sulfathiazole. This delivery behavior was compared with that shown by other solids that were prepared as models to assess the effect of the hapten and its interaction with antibody in the dye delivery control in the presence of the antigen.

[EN] An electronic tongue (ET) based on pulse voltammetry containing a set of eight metallic electrodes (Au, Pt, Ir, Rh, Cu, Co, Ni and Ag) encapsulated on a stainless steel cylinder has been used to discriminate and predict levels of nerve agent mimics in aqueous environments. Analysis including principal component analysis (PCA) and partial least square techniques (PLS) have been applied for data management and prediction models. A good discrimination from other organophosphorous derivatives was found for the nerve agent simulants diethyl-chlorophosphate (DCP) and diethyl-cyanophosphate (DCNP)., We thank the Ministerio de Ciencia y Tecnologia (project CTQ2006-15456-C04-01), and Universidad Politecnica de Valencia (project PAID-06-07-3243) for support. I.C. thanks the Universidad Politecnica de Valencia for a Doctoral Fellowship.

A new hybrid system for surfactant removal from water has been developed using mesoporous material (MCM-41) functionalised with suitable binding groups. Solid S1, S2 and S3 were prepared by reaction of the mesoporous material with N-methyl-N′-(propyltrimethoxysilyl)imidazolium chloride, (3-aminopropyl)trimethoxysilane or 4-[(triethoxysilylpropylthio)methyl]pyridine, respectively. The functionalised materials were characterised following standard solid-state techniques. The final prepared solids consist of a siliceous MCM-41-type mesoporous support with the surface decorated by imidazolium, amine and pyridine binding groups suitable for anion coordination. Equilibrium adsorption studies of linear alkylbenzenesulfonate (LAS) using S1, S2 and S3 in water have been carried out. The obtained adsorption data were correlated with a Langmuir isotherm model that gives an acceptable description of the experimental data. The maximum surfactant uptake/binding site (mol mol–1) and the surfactant adsorption capacity (mmol g–1) for materials S1, S2 and S3 were calculated. S1 shows a positive-charged functionalised surface that is independent of the pH of the solution, whereas S2 and S3 are functionalised with neutral groups that need to be protonated in order to display electrostatic binding interactions with the anionic surfactants. Therefore, whereas the adsorption capacity of S1 is pH-independent, S2 and S3 display larger LAS adsorption at acidic pH. The adsorption ability at a certain pH follows the order S1 >> S3 > S2. A remarkable maximum surfactant adsorption of 1.5 mmol per gram of material was observed for S1 at neutral pH. S2 and S3 behave as poorer adsorbents and show maximum surfactant adsorption of 0.197 and 0.335 mmol per gram of material, respectively, at pH 2.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

To help understand the mechanism of chemical peeling of boron nitride nanotubes, single-walled model systems have been studied using Density Functional Theory. Dimethyl sulfoxide acts as a water tr...

2,4,6-Triphenylthiopyrylium functionalized with an aza-oxa-thia macrocycle is able to selectively recognize Hg2+ cation by a color change and Cu2+ cation by a remarkable significant emission enhancement.

Based on the cross-sensitivity shown by certain metal electrodes for some anions in a liquid media, an array of five potentiometric electrodes (Au, Ag, Pt, Cu and Zn) has been used as an electronic tongue device for the recognition and prediction of common anions chloride, sulfate and bicarbonate in mineral waters. The recognition testing studies included measurements of potential (emf) on solutions of pure salts, mixtures of salt and some mineral waters. Predictions were performed by using partial least square. A good discrimination between different water samples by PCA analysis was found as well as an adequate prediction of the concentration of chloride and sulfate.

The development of fast and reliable protocols to determine the characteristics of building materials is of importance in order to develop environmentally friendly houses with an efficient energy design. In this article heat flux evolution on different types of clay and concrete bricks has been studied using a guarded hot-plate. The studied bricks were purchased from local commercially available sources and included a solid face brick and a range of honeycombed and perforated bricks. From the data collected a new model to study heat flux is proposed. This model is based on the shape of the typical sigmoidal curves observed for the time dependent heat flux evolution. The model allows the calculation of the thermal resistance (R) and the heat flux in the steady-state (φ∞). The model also calculates two new parameters, tB and τB. tB represents the time at which half φ∞ is attained. This parameter (tB) has additionally been found to be dependent on the thermal diffusivity and the geometric characteristics of the brick.

This paper focuses on the removal of nitro substituted polycyclic aromatic hydrocarbon compounds (NPAHs) from water using low cost synthesized zirconium phosphate mesoporous materials. These materials are lamellar type incorporating n-alkyl-(n = 12 and n = 16) trimethylamonium bromide molecules with different concentrations. For comparison of their performance as adsorbents and in the recovery of NPAH, their results were compared with commercial ENVI-18 extraction tubes and three dimensional type material incorporating hexadecyl-trimethyl ammonium bromide. The adsorption yield for the new materials were almost 100% and the recovery factors with dichloromethane as eluent was nearly 100%. Best results were obtained by preparing lamellar zirconium and titanium phosphates in the presence of n-dodecyl-trimethylammonium. This material has several environmental advantages because zirconium salts are non-toxic and their synthesis costs is relatively small.

Electronic tongues were developed some ten years ago. These systems consist of an array of nonspecific sensors and a signal processing unit. The sensor signals are processed by pattern recognition methods which makes possible the extraction of specific properties from the sample. Depending on the calibration, attributes such as quality or taste can be determined. These systems also detect changes in the sample that they are not calibrated for which makes possible the detection of anomalous occurrences. Such sensor systems are suitable for process control and surveillance. Important factors are the sensitivity and stability, specifically the sensor's ability to respond to small changes and to provide true and reproducible readings over time. Problems with sensor stability are commonly referred to as drift. The major topic of this thesis is the improvement of long term stability for electronic tongues used in liquid process applications. Drift counteractions, such as renewal of the electrode surface by polishing, was compared with mathematical correction methods. Since drift is induced by the environment of the sensor, mathematical correctional actions must include reference samples and the induced drift must be identical between measurements. These conditions restrict and complicate the use of mathematical drift counteractions. It was found that mechanical polishing renewed the electrode surfaces, and that the induced drift was unique for each sample. The sample induced drift pattern can be treated as information from the sample, but only if the sensors are renewable in a repeatable way. Applications where polishing the electrode surfaces are necessary to obtain repeatable analyses are described, such as the detection of urea and measurements in corrosive environments such as wine. Electrochemical oxidation of urea in water is difficult to use for analytical purposes because of residues left on the electrode surface. An important result from this thesis is that mechanical cleaning of the electrodes between samples gives sensor signals that are both repeatable and proportional to the concentrations of urea and glucose. An experimental design was employed for optimal effect of the calibration of urea in the presence of glucose as a disturbance in the sample. The goal was to minimize the correlation between the two analytes. This made possible the prediction of both analyte concentrations. Wine is a complex sample to analyze with many sources of disturbances for electrochemical measurements. The carefully planned experiments and calibrations reported in this thesis minimized covariance and background effects. A method for prediction of bisulfite, histamine and ascorbic acid concentrations in wine was developed. The method was tested with spiked samples of white-, red-, rose-wines and even apple juice. The reproducibility of the measurements was excellent. Since polishing renewed the electrodes between measurements, a validation performed one month after the calibration was also predicted with good results. This demonstrated that the renewal of the electrodes eliminated special requirements for maintenance and storage of the sensor. Drinking water surveillance has been performed with an electronic tongue. The potential of using a voltammetric electronic tongue for multicomponent analysis of compounds in drinking water has been evaluated. By using such a non-selective sensor it was possible to detect anomalies without the need of a specific sensor for each type of event. The device can be calibrated for the most likely events, and it can also be used for sensing and alarm when exceptional events occur. The detection of surface active species like detergents is normally done by titration. An in-line sensor that could control the washing process by detecting the concentrations of detergents during the different steps in a wash cycle could enhance the performance of washing machines. An electronic tongue was used to predict concentrations of detergents in samples from different stages in the washing procedure. The tongue was compared with a much simpler conductivity meter, and due to the covariation of supporting electrolyte, both sensors were able to predict concentrations of ionic surfactants. The electronic tongue showed promising results in predicting also non ionic surfactants where the conductivity meter failed. The detection mechanism was probably due to shielding the electrode surface from electro active species in the samples.

The surface-enhanced Raman scattering (SERS) of p-benzoquinone (Q) adsorbed on silver nanoclusters (Agn) reported by Tripathi (J. Am. Chem. Soc. 2003, 125, 1179) is analyzed by means of high-level ab initio calculations. CASPT2 energies of the Ag2−Q model confirm the charge transfer character of the adsorption (Agn + Q → Agn+−Q−•), yielding the semiquinone radical anion (Q−•). On the contrary, we demonstrate that the selective enhancement shown by mode 7a in SERS is due to a resonant process between the 2B2g ground state and the 2Au excited doublet of Q−•. This is an unexpected result given that the electronic spectrum is dominated by the strong dipole-allowed 2B2g → 2B3u transition. Therefore, that spectrum is, to our knowledge, the only reported surface-enhanced resonance Raman scattering spectrum involving two doublet states of an adsorbate.

Bifunctionalised hybrid silica nanoparticles have been synthesised and characterised, and their optical emission properties in the presence of certain anions in acetonitrile solutions have been studied. The alkoxysilane derivatives N-butyl-N′-[3-(trimethoxysilyl)propyl]thiourea (1), N-phenyl-N′-[3-(trimethoxysilyl)propyl]thiourea (2) and 3-[(anthracen-10-yl)methylthio]propyltriethoxysilane (3) were prepared and used to functionalise uncoated LUDOX silica nanoparticles with a mean diameter of 18 ± 2 nm. The functionalisation of the nanoparticle surfaces was carried out by two different approaches. The first approach relies on the consecutive grafting of the two subunits. In this protocol, the nanoparticles were first functionalised with anthracene derivative 3 (solid NA), and then treated with the corresponding binding sites 1 or 2 to result in the NA-Pt3 and NA-Bt3 solids. The second approach deals with the simultaneous grafting of 1 or 2 and the signalling subunit 3 in different ratios. This method was used for the preparation of the NA1Pt1, NA1Bt1, NA1Pt3 and NA1Bt3 nanoparticles. The bifunctionalised silica nanoparticles were characterised by using standard techniques. Acetonitrile suspensions of NA nanoparticles (5 mg in 20 mL) showed anthracene bands centred at ca. 350, 370 and 390 nm. Upon excitation at 365 nm, a typical emission band with fine structure in the 390–450 nm range was observed. Similar absorption and emission spectra were found for the bifunctionalised nanoparticles. The work is completed with a prospective study of the fluorescence of the prepared nanoparticles in the presence of organic (acetate, benzoate) and inorganic (F–, Cl–, Br–, CN–, HSO4– and H2PO4–) anions. The apparent binding constants (adsorption constants) for the interaction of NA-Pt3 with anions in acetonitrile were determined by performing a Langmuir-type analysis of fluorescence titration data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The synthesis, photophysical properties, protonation, and metal-ion coordination features of a family of nine aniline-based symmetrical squaraine derivatives are reported. The squaraine scaffold displays very attractive photophysical properties for a signalling unit. These dyes show absorption and weakly Stokes-shifted, mirror-image-shaped emission bands in the visible spectral range and there are no hints of multiple emission bands. The mono-exponential fluorescence decay kinetics observed for all the derivatives indicate that only one excited state is involved in the emission. These data stress the interpretation that squaraines can be regarded as polymethine-type dyes. From a coordination chemistry point of view, the squaraines possess four potential binding sites; that is, two nitrogen atoms from the anilino groups and two oxygen atoms from the central C(4)O(2) four-membered ring. These coordination sites are part of a cross-conjugated pi-system and coordination events with protons or certain metal ions affect the electronic properties of the delocalised pi-system dramatically, resulting in a rich modulation of the colour of the squaraines. The absorption band at around 640 nm is blue-shifted when coordination at the anilino nitrogen atoms occurs, whereas coordination to the C(2)O(4) oxygen atoms results in the development of red-shifted bands. Addition of more than one equivalent of protons or metal cations could additionally entail mixed N,O- or N,N-coordinated complexes, manifested in the development of a broad band at 480 nm or complete bleaching in the visible range, respectively. Analysis of the spectrophotometric titration data with HYPERQUAD yielded the macroscopic and microscopic stability constants of the complexes. Theoretical modelling of the various protonated species by molecular mechanics methods and consideration of some of the title dyes within the framework of molecular chemosensing and molecular-scale "logic gates" complement this contribution.

Dual-function hybrid material U1 was designed for simultaneous chromofluorogenic detection and removal of Hg(2+) in an aqueous environment. Mesoporous material UVM-7 (MCM41 type) with homogeneously distributed pores of about 2-3 nm in size, a large specific surface area exceeding 1000 m(2) g(-1), and nanoscale particles was used as an inorganic support. The mesoporous solid is decorated with thiol groups that were treated with squaraine dye III to give a 2,4-bis(4-dialkylaminophenyl)-3-hydroxy-4-alkylsulfanylcyclobut-2-enone (APC) derivative that is covalently anchored to the inorganic silica matrix. The solid was characterised by various techniques including X-ray diffraction, transmission electron microscopy, Raman spectroscopy, and nitrogen adsorption. This hybrid solid is the chemodosimeter for Hg(2+) detection. Hg(2+) reacts with the APC fragment in U1 with release of the squaraine dye into the solution, which turns deep blue and fluoresces strongly. Naked-eye Hg(2+) detection is thus accomplished in an easy-to-use procedure. In contrast, U1 remains silent in the presence of other thiophilic transition metal ions, alkali and alkaline earth metal ions, or anions ubiquitously present in water such as chloride, carbonate, sulfate, and phosphate. Material U1 acts not only as chemodosimeter that signals the presence of Hg(2+) down to parts-per-billion concentrations, but at the same time is also an excellent adsorbent for the removal of mercury cations from aqueous solutions. The amount of adsorbed mercury ranges from 0.7 to 1.7 mmol g(-1), depending on the degree of functionalisation. In addition, hybrid material U1 can be regenerated for both sensing and removal purposes. As far as we know, U1 is the first example of a promising new class of polyfunctional hybrid supports that can be used as both remediation and alarm systems by selective signalling and removal of target species of environmental importance. Model compounds based on silica gel (G1), fumed silica (F1), and micrometre-sized MCM-41 scaffolds (M1) were also prepared and studied for comparative purposes.