A Direct Catalytic Ethanol Fuel Cell (DCEFC) Modified by LDHs, or by Catalase-LDHs, and Improvement in Its Kinetic Performance: Applications for Human Saliva and Disinfectant Products for COVID-19.

In this work, it has been experimentally proven that the kinetic performance of a common Direct Catalytic Ethanol Fuel Cell (DCEFC) can be increased by introducing nanostructured (Zn,Al(OH))NO·HO Layered Double Hydroxides (LDHs) into the anode compartment. Carrying out the measurements with the open-circuit voltage method and using a kinetic format, it has been shown that the introduction of LDHs in the anodic compartment implies a 1.3-fold increase in the calibration sensitivity of the method.

Novel Electrochemical Sensors Based on L-Proline Assisted LDH for HO Determination in Healthy and Diabetic Urine.

In this paper, a novel non-enzymatic modified glassy carbon (GC) sensor, of the (GC-Ag)-catalytic proline-assisted LDH type, for HO determination was fabricated, studied, characterized and employed to determine the hydrogen peroxide content in healthy and diabetic human urine. LDH (whose composition can be schematized as [ZnAl (OH)] NO·nHO) is glued to glassy carbon by means of silver paste, while proline, which increases the catalytic properties of LDH, is used free in solution in the phosphate buffer. A voltametric survey was first conducted to ascertain the positive effect induced by the presence of proline, i.

Simple Yeast-Direct Catalytic Fuel Cell Bio-Device: Analytical Results and Energetic Properties.

This paper reports the analytical detection and energetic properties of a glucose-fed Direct Catalytic Fuel Cell (DCFC) operated in association with yeast cells (Saccharomyces Cerevisiae). The cell was tested in a potentiostatic mode, and the operating conditions were optimized to maximize the current produced by a given concentration of glucose. Results indicate that the DCFC is characterized by a glucose detection limit of the order to 21 mmol L.

Direct Catalytic Fuel Cell Device Coupled to Chemometric Methods to Detect Organic Compounds of Pharmaceutical and Biomedical Interest.

Making use of a small direct methanol fuel cell device (DMFC), used as an analytical sensor, chemometric methods, organic compounds very different from one another, can be determined qualitatively and quantitatively. In this research, the following seven different organic compounds of pharmaceutical and biomedical interest, having in common only one -OH group, were considered: chloramphenicol, imipenem, methanol, ethanol, propanol, atropine and cortisone. From a quantitative point of view, the traditional approach, involving the building of individual calibration curves, which allow the quantitative determination of the corresponding organic compounds, even if with different sensitivities, was followed.

Direct Methanol (or Ethanol) Fuel Cell as Enzymatic or Non-Enzymatic Device, Used to Check Ethanol in Several Pharmaceutical and Forensic Samples.

It was already demonstrated by our research group that a direct catalytic methanol (or ethanol) fuel cell (DMFC) device can be used also for analytical purposes, such as the determination of ethanol content in beverages. In the present research we extended the application to the analysis of several ethanol-based pharmaceutical products, i.e.

3-methylcrotonyl Coenzyme A (CoA) carboxylase complex is involved in the Xanthomonas citri subsp. citri lifestyle during citrus infection.

Citrus canker is a disease caused by the phytopathogen Xanthomonas citri subsp. citri (Xcc), bacterium which is unable to survive out of the host for extended periods of time. Once established inside the plant, the pathogen must compete for resources and evade the defenses of the host cell.

Ethanol traces in natural waters checked using a new DMFC enzymatic device.

The use of fuels with strong percentage of ethanol that is done in countries such as Brazil and Australia causes a more and more relevant presence of traces of ethanol in natural waters. The ethanol present in these fuels seems to contribute to increase, through various mechanisms, the concentration of hydrocarbons in the same waters and soil. The ethanol content in natural waters must therefore be monitored frequently.

Comparison between a Direct-Flow SPR Immunosensor for Ampicillin and a Competitive Conventional Amperometric Device: Analytical Features and Possible Applications to Real Samples.

In this research, we developed a direct-flow surface plasmon resonance (SPR) immunosensor for ampicillin to perform direct, simple, and fast measurements of this important antibiotic. In order to better evaluate the performance, it was compared with a conventional amperometric immunosensor, working with a competitive format with the aim of finding out experimental real advantages and disadvantages of two respective methods. Results showed that certain analytical features of the new SPR immunodevice, such as the lower limit of detection (LOD) value and the width of the linear range, are poorer than those of a conventional amperometric immunosensor, which adversely affects the application to samples such as natural waters.

The infectious intracellular lifestyle of Salmonella enterica relies on the adaptation to nutritional conditions within the Salmonella-containing vacuole.

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative pathogen that causes various host-specific diseases. During their life cycle, Salmonellae survive frequent exposures to a variety of environmental stresses, e.

Bioethanol in Biofuels Checked by an Amperometric Organic Phase Enzyme Electrode (OPEE) Working in "Substrate Antagonism" Format.

The bioethanol content of two samples of biofuels was determined directly, after simple dilution in decane, by means of an amperometric catalase enzyme biosensor working in the organic phase, based on substrate antagonisms format. The results were good from the point of view of accuracy, and satisfactory for what concerns the recovery test by the standard addition method. Limit of detection (LOD) was on the order of 2.

Application of near infrared spectroscopy (NIR), X-ray fluorescence (XRF) and chemometrics to the differentiation of marmora samples from the Mediterranean basin.

Near-infrared (NIR) and X-ray fluorescence spectra were recorded for 15 different samples of marmora, from the Mediterranean Basin and of different colours. After appropriate pretreatment (SNV transform + second derivative), the results were subjected to principal component analysis (PCA) treatment with a view to differentiating them. The observed differences among the samples were chemically interpreted by highlighting the NIR wavelengths and minerals, respectively, contributing the most to the PCA models.

A Flow SPR Immunosensor Based on a Sandwich Direct Method.

In this study, we report the development of an SPR (Surface Plasmon Resonance) immunosensor for the detection of ampicillin, operating under flow conditions. SPR sensors based on both direct (with the immobilization of the antibody) and competitive (with the immobilization of the antigen) methods did not allow the detection of ampicillin. Therefore, a sandwich-based sensor was developed which showed a good linear response towards ampicillin between 10(-3) and 10(-1) M, a measurement time of ≤20 min and a high selectivity both towards β-lactam antibiotics and antibiotics of different classes.

A new surface plasmon resonance immunosensor for triazine pesticide determination in bovine milk: a comparison with conventional amperometric and screen-printed immunodevices.

A detailed comparison was made of the analytical features of a new Surface Plasmon Resonance (SPR) immunodevice for triazine pesticide determination with those of two other amperometric (conventional and screen-printed) immunosensors and the advantages and disadvantages of the SPR method were thoroughly investigated. For conventional amperometric and screen-printed devices, "competitive" assays were used; conversely, the SPR transduction technique allowed a "direct" measurement format to be used. As far as the main analytical data are concerned, the SPR method does not seem to offer substantial advantages.

Suitable classification of mortars from ancient Roman and Renaissance frescoes using thermal analysis and chemometrics.

Background: Literature on mortars has mainly focused on the identification and characterization of their components in order to assign them to a specific historical period, after accurate classification. For this purpose, different analytical techniques have been proposed. Aim of the present study was to verify whether the combination of thermal analysis and chemometric methods could be used to obtain a fast but correct classification of ancient mortar samples of different ages (Roman era and Renaissance).

Amperometric enzyme sensor to check the total antioxidant capacity of several mixed berries. Comparison with two other spectrophotometric and fluorimetric methods.

The aim of this research was to test the correctness of response of a superoxide dismutase amperometric biosensor used for the purpose of measuring and ranking the total antioxidant capacity of several systematically analysed mixed berries. Several methods are described in the literature for determining antioxidant capacity, each culminating in the construction of an antioxidant capacity scale and each using its own unit of measurement. It was therefore endeavoured to correlate and compare the results obtained using the present amperometric biosensor method with those resulting from two other different methods for determining the total antioxidant capacity selected from among those more frequently cited in the literature.

Determination of traces of several pesticides in sunflower oil using organic phase immuno electrodes (OPIEs).

Testing for traces of different pesticides (triazinic, organophosphates and chlorurates), present in hydrophobic matrices such as sunflower oil was checked using new immunosensors working in organic solvent mixtures (OPIEs). The competitive process took place in an n-hexane-chloroform 75% (V/V) mixture, while the subsequent final enzymatic measurement was performed in decane using tert-butylhydroperoxide as substrate of the enzymatic reaction. A Clark electrode was used as transducer and peroxidase enzyme as marker.

Agent orange herbicides, organophosphate and triazinic pesticides analysis in olive oil and industrial oil mill waste effluents using new organic phase immunosensors.

New immunosensors working in organic solvent mixtures (OPIEs) for the analysis of traces of different pesticides (triazinic, organophosphates and chlorurates) present in hydrophobic matrices such as olive oil were developed and tested. A Clark electrode was used as transducer and peroxidase enzyme as marker. The competitive process took place in a chloroform-hexane 50% (V/V) mixture, while the subsequent enzymatic final measurement was performed in decane and using tert-butylhydroperoxide as substrate of the enzymatic reaction.

Simple and suitable immunosensor for β-lactam antibiotics analysis in real matrixes: milk, serum, urine.

The anti-penicillin G was conjugated to avidin-peroxidase and biotin to obtain immunogen and competitor which were then used to develop a competitive immunosensor assay for the detection of penicillin G and other β-lactam antibiotics, with Kaff values of the order of 10(8) M(-1). The new immunosensor appears to afford a number of advantages in terms of sensitivity, possibility of "in situ" analysis, but especially of simplicity and lower costs, compared with other existing devices, or different chemical instrumental methods reported in the literature and used for the analysis of β-lactam compounds. Satisfactory results were found in the analysis of real matrixes and good recoveries were obtained by applying the standard addition method to spiked milk, urine, serum and drug samples.

New approach to the differentiation of marble samples using thermal analysis and chemometrics in order to identify provenance.

Background: The possibility of applying a novel chemometric approach which could allow the differentiation of marble samples, all from different quarries located in the Mediterranean basin and frequently used in ancient times for artistic purposes, was investigated. By suggesting tentative or allowing to rule out unlikely attributions, this kind of differentiation could, indeed, be of valuable support to restorers and other professionals in the field of cultural heritage. EXPERIMENTAL DATA WERE OBTAINED ONLY USING THERMAL ANALYTICAL TECHNIQUES: Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA).

Archaeometric classification of ancient human fossil bones, with particular attention to their carbonate content, using chemometrics, thermogravimetry and ICP emission.

Background: The potential of coupling chemometric data processing techniques to thermal analysis for formulating an "archaeometric" classification of fossil bones was investigated. Moreover, the possibility of integrating the outcomes of this approach with the results of inductively coupled plasma (ICP) emission spectroscopy for an anthropological interpretation of the observed patterns was also examined.

Results: Several fossil bone samples coming from the necropolis of El Geili, in the middle Nile, an important archaeological site, were first of all subjected to thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis and the main steps of the curves were analyzed.

Reducing the pollutant load of olive mill wastewater by photocatalytic membranes and monitoring the process using both tyrosinase biosensor and COD test.

Photocatalytic technique had already been employed in the treatment of olive mill wastewater (OMW) using the photocatalysis in suspension. The coupling of photocatalytic and membrane techniques should result in a very powerful process bringing great innovation to OMW depollution. Despite the potential advantages using these hybrid photoreactors, research on the combined use of photocatalysis and membranes has so far not been sufficiently developed.

Detailed kinetic and chemometric study of the cellulose thermal breakdown in artificially aged and non aged commercial paper. Different methods for computing activation energy as an assessment model in archaeometric applications.

Background: The thermal oxidative degradation of aged and non aged cellulose samples of commercial paper was studied using thermogravimetry and derivative thermogravimetry under a forced air flow up to 800°C.

Results: TG and DTG data were processed using two non-isothermal-based model-fitting methods and one based on linear least squares to calculate Ea trend values, measured as a function of artificially induced sample age. The Ea trends thus obtained were compared in order to assess their potential for yielding archaeometric curves.