Catalytic fuel cell used as an analytical tool for methanol and ethanol determination. Application to ethanol determination in alcoholic beverages

A small direct catalytic methanol 'fuel cell' was used for analytical purposes. Three different formats were investigated for methanol and ethanol determination: two different Open Circuit Voltage (OCV) formats and a potentiostatic (i.e. amperometric) format; the latter was used if the current supplied by the cell was recorded. The measurement times using one or other of these three formats were much different. The time required by the potentiostatic format was more short for a suitable analytical measurement. The cell was used to check ethanol content in several commercial wine and beer samples and the possibility of using the fuel cell for the analytical measures in real samples, discussed. Lastly the results were compared with those obtained using two conventional amperometric enzyme sensors and statistical tests carried out. (C) 2016 Elsevier Ltd. All rights reserved

Insight from an Italian Delphi Consensus on EVAR feasibility outside the instruction for use: the SAFE EVAR Study

BACKGROUND: The SAfety and FEasibility of standard EVAR outside the instruction for use (SAFE-EVAR) Study was designed to define the attitude of Italian vascular surgeons towards the use of standard endovascular repair (EVAR) for infrarenal abdominal aortic aneurysm (AAA) outside the instruction for use (IFU) through a Delphi consensus endorsed by the Italian Society of Vascular and Endovascular Surgery (Societa Italiana di Chirurgia Vascolare ed Endovascolare - SICVE). METHODS: A questionnaire consisting of 26 statements was developed, validated by an 18 -member Advisory Board, and then sent to 600 Italian vascular surgeons. The Delphi process was structured in three subsequent rounds which took place between April and June 2023. In the first two rounds, respondents could indicate one of the following five degrees of agreement: 1) strongly agree; 2) partially agree; 3) neither agree nor disagree; 4) partially disagree; 5) strongly disagree; while in the third round only three different choices were proposed: 1) agree; 2) neither agree nor disagree; 3) disagree. We considered the consensus reached when >70% of respondents agreed on one of the options. After the conclusion of each round, a report describing the percentage distribution of the answers was sent to all the participants. RESULTS: Two -hundred -forty-four (40.6%) Italian Vascular Surgeons agreed to participate the first round of the Delphi Consensus; the second and the third rounds of the Delphi collected 230 responders (94.3% of the first -round responders). Four statements (15.4%) reached a consensus in the first rounds. Among the 22 remaining statements, one more consensus (3.8%) was achieved in the second round. Finally, seven more statements (26.9%) reached a consensus in the simplified last round. Globally, a consensus was reached for almost half of the proposed statements (46.1%). CONCLUSIONS: The relatively low consensus rate obtained in this Delphi seems to confirm the discrepancy between Guideline recommendations and daily clinical practice. The data collected could represent the source for a possible guidelines' revision and the proposal of specific Good Practice Points in all those aspects with only little evidence available

Three different sensor methods for methanol and ethanol determination

This book contains a selection of papers presented at the Second National Conference on Sensors held in Rome 19-21 February 2014. The conference highlighted state-of-the-art results from both theoretical and applied research in the field of sensors and related technologies. This book presents material in an interdisciplinary approach, covering many aspects of the disciplines related to sensors, including physics, chemistry, materials science, biology and applications. · Provides a selection of the best papers from the Second Italian National Conference on Sensors; · Covers a broad range of topics relating to sensors and microsystems, including physics, chemistry, materials science, biology and applications; · Offers interdisciplinary coverage, aimed at defining a common ground for sensors beyond the specific differences among the different particular implementation of sensors

Ethanol Determination in Alcoholic Beverages Using Two Different Amperometric Enzyme Sensors

Two different enzyme electrodes for the determination of ethanol in alcoholic beverages were developed by immobilizing alcohol oxidase or catalase in a k-Carrageenan gel layer overlapping an amperometric gaseous diffusion Clark type oxygen electrode. The response of biosensors toward standard solutions of ethanol,methanol, n-propanol, n-butanol, ethylenglycol and glycerol was recorded, compared and discussed. In the characterization studies of the biosensors several parameters such as pH, operational stability, response time, analysis time and calibration repeatability, between-days and between-electrodes, calibration reproducibility, linearity, and sensitivity, were studied. Finally by using the developed biosensors, the ethanol concentration of several commercial wine and beer samples was determined. The results, obtained with the two enzyme electrodes, were compared and the correlation evaluated by statistic tests. The biosensor method using catalase enzyme seemed to be the most suitable of the two enzyme devices for a selective and less expensive determination of ethanol in alcoholic beverages. The catalase enzyme electrode actually showed the greatest selectivity to ethanol, of all the alcohols tested. The response of the catalase biosensor was not influenced by the presence of the methanol in particular and its operational stability is significantly higher than that of the alcohol oxidase sensor. The only drawback associated with the use of the catalase biosensor, compared to the method based on alcohol oxidase, is the slightly increased time required to perform the ethanol analysis in each sample of alcoholic beverage

THREE DIFFERENT SENSOR METHODS FOR METHANOL AND ETHANOL DETERMINATION.

Ethanol and methanol are two important alcohols used for different purposes. Consequently, also the analytical methods used to determine them are of considerable interest. Our team is therefore developing three different sensor-based methods for ethanol and methanol determination. Two of these consist of different enzyme electrodes and have been developed by immobilizing either alcohol oxidase or catalase in a kappa-Carrageenan gel layer overlapping an amperometric gaseous diffusion Clark type oxygen electrode. The variation of the oxygen concentration in the aqueous solution due to the enzymatic reactions was measured at a constant applied potential of – 650 mV. The responses of these biosensors toward standard solutions of methanol or ethanol were recorded, compared and discussed. In the case of the catalase electrode, the measurement was performed by adding hydrogen peroxide to a buffer solution which was diffused through the dialysis membrane towards the enzymatic layer where the reaction catalysed by the catalase enzyme took place: H2O2 1/2 O2 + H2O. Since this reaction led to the production of oxygen, the concentration of the latter in the measurement solution increased. This increase triggered an increase in the cathodic current measured which increased from the original value to a new value corresponding to a new stationary state. At this stage further additions were made (equal to 20 μL) of a standard solution of 0.008 mol L-1 of ethanol or methanol; after each addition a reaction of the following type occurred which was catalyzed by catalase: CH3CH2OH + H2O2 CH3CHO + 2 H2O. The second reaction removed part of the H2O2 substrate from the first reaction, which was slowed down; this slowdown was accompanied by a decrease in the level of oxygen produced in the solution during the first reaction; this decrease was evidenced by the decrease in the measured cathodic current which attained a new stationary state after each addition of alcohol solution. The current variation was read off after each alcohol addition [1]. With the biosensor operating with alcohol oxidase the operating procedure was much simpler as it consisted of directly making successive additions of the standard ethanol or methanol solution to a buffer solution in which the measurement was being performed. After each addition a reaction catalyzed by the alcohol oxidase enzyme of the following type took place: CH3CH2OH + O2 CH3CHO + H2O2. The reaction led to the oxygen present in the solution being consumed with a consequent decrease in the cathodic current measured until a new stationary state was reached. Also in this case, after each addition, the current variation was read off. All the experiments were carried out in a reaction cell thermostated at 23°C containing 15 mL of 0.05 mol L-1 phosphate buffer solution. The effect of pH on the response of the electrodes was investigated in detail and the best pH was found to be 7.5 for the catalase electrode and 8.0 for the alcohol oxidase electrode, respectively. The catalase biosensor displayed a much greater sensitivity to ethanol than to methanol, unlike the alcohol oxidase biosensor. It also displayed a stability and a life-time at least triple that of the alcohol oxidase biosensor as well as an LOD at least one decade lower. It also displayed a better repeatability and reproducibilty for ethanol and methanol solutions. The alcohol oxidase biosensor was instead found to be more sensitive to methanol than to ethanol but allowed the test to be carried out slightly faster than with the catalase device. In conclusion, our team is now investigating the feasibility of using a small catalytic ‘fuel cell’ originally constructed for the purpose of obtaining energy from methanol or ethanol but now adapted for analytical purposes [2,3]. The intention is to see whether this kind of device can also be used for ethanol and methanol determination. To this end water-alcohol solutions containing increasing percentages of ethanol or methanol are added to the cell, then following the potential increase that occurs at two electrodes of the cell and lastly reading off the maximum potential obtained with each addition. Although this part of the research is only at the preliminary stage it has already been possible to obtain calibration curves for both methanol and ethanol. A comparison of the linearit

Looking if any correlation exists between the total antioxidant capacity and polyphenol concentration (measured using two different enzyme sensors) in several food or feed based vegetables and pharmaceutical integrators

he principal aim of the present research has been to check if any correlation exists between the total antioxidant capacity (TAOC) value and the total polyphenols content (TPC) of several food, or beverages and feed samples based vegetables. The research was also extended to several food supplements currently sold as pharmaceutical integrators. © Springer International Publishing AG 2018

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., pharmaceutical tinctures (dyes) and disinfectants. In recent work we have also shown that the use of alcohol dehydrogenase enzyme as a component of the anodic section of a direct catalytic methanol (or ethanol) fuel cell significantly improves the performance of a simple DMFC device, making it more suitable to measure ethanol (or methanol) in real samples by this cell. At the same time, we have also shown that DMFC can respond to certain organic compounds that are more complex than methanol and ethanol and having R(R’)CH-OH group in the molecule. Firstly, pharmaceutical dyes were analyzed for their ethanol content using the simple catalytic DMFC device, with good accuracy and precision. The results are illustrated in the present paper. Additionally, a detailed investigation carried out on commercial denatured alcoholic samples evidenced several interferences due to the contained additives. Secondly, we hypothesized that by using the enzymatic fuel cell it would be possible to improve the determination, for instance, of certain antibiotics, such as imipenem, or else carry out determinations of ethanol content in saliva and serum (simulating forensic tests, correlated to drivers “breath test„); even if this has already been hypothesized in previous papers, the present study is the first to perform them experimentally, obtaining satisfactory results. In practice, all of the goals which we proposed were reached, confirming the remarkable opportunities of the enzymatic (or non-enzymatic) DMFC device

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−1. The cell was used to estimate the “pool” of carbohydrate content in commercial soft drinks. Furthermore, the use of different carbohydrates, such as fructose and sucrose, has been shown to result in a good current yield

O Significado Actual do Karaté - Arte Marcial / Desporto de Combate?

Analisando sumariamente os suportes conceptuais dos significados dos conceitos de "arte" e "marcial", desconstruindo o significado do conceito de técnica na base da pedagogia do ensino nos desportos de combate e artes marciais com destaque para o Karaté, passa pelo significado do desporto humanizante. Conclui-se que não há razão para dicotomizar divergentemente o karaté em arte marcial ou desporto de combate, utilizando argumentações ideológicas ou desequilibradas pela ignorância cultural em um dos significantes, pelo que elogia a urgência permanente de comunicação entre partes