1,721,019 research outputs found
Further development on DMFC device used for analytical purpose: real applications in the pharmaceutical field and possible in biological fluids
No full textThe analytical research devoted to the utilization of the direct methanol fuel cell (DMFC) for analytical purposes has been continued. The research reported in this paper concerns two points, one of which was the possibility of improving the features, from the analytical point of view, of a catalytic fuel cell for methanol and ethanol, by introducing an enzyme, immobilized into a dialysis membrane small bag, in the anodic area of the fuel cell. This objective has been fully achieved, particularly using the enzyme alcohol dehydrogenase, which has increased the sensitivity of the method and reduced dramatically the response time of the cell. The second point concerned the opportunity to determine two particular antibiotics having an alcohol functional group in their molecule, that is, imipenem and chloramphenicol. Also, this goal has been reached, even if the sensitivity of the method is not so high
Costanti di affinità,selettività,e applicazione dell‘equazione di Hill ad un nuovo OPIE per l’analisi dei pesticidi triazinici in olio di oliva.
No full textCostanti di affinità,selettività,e applicazione dell‘equazione di Hill ad un nuovo OPIE per l’analisi dei pesticidi triazinici in olio di oliva
Determination of lactoferrin content and the total antioxidant capacity, in animal, or powdered milks and food supplements available in drugstore, using biosensors. Study of the possible correlation between them
No full textBackground: Recently also food supplements for adults containing lactoferrin have appeared on the market. Recent experimental results support the proposal that oral supplements of bovine lactoferrin may be a useful adjunct in the modulation of immune activity, in particular T-cell activation and antioxidant status. Objective: The present research shows as it is possible to determine in a successfully and inexpensive way, respectively using an immunosensor and an enzyme sensor, both the lactoferrin content, and the total antioxidant capacity values in real samples. Food samples analyzed to this purpose have been food integrators containing lactoferrin, available in drug stores, edible animal milk samples and dairy derivatives, such as powdered milk, or yogurt. Method: Using two sensors, optimized in previous researches, we simultaneously measured lactoferrin concentration and antioxidant capacity in food supplements sold in drugstores as well as in cow, goat, powdered milk and in yoghurt. Results: It was also tried to verify if exists between found lactoferrin content and total antioxidant capacity data values, any correlation. Actually some correlation has been found in milk samples, but only in one of the analyzed food integrators this correlation has been evidenced. Results emphasize as the lactoferrin content was clearly shown to contribute to the total antioxidant capacity in both food supplements and various milk and milk derivative samples. Conclusion: The present research also proved that it was possible to perform a suitable and fast determination of lactoferrin in the food supplements tested and to compare the lactoferrin concentration, declared by the manufacturers, with the experimental measure content value, using an inexpensive immunosensor, instead other more complex and costly instrumental methods. At this stage of the research it was not always possible to prove a direct correlation between lactoferrin concentration and (TAOC) value in all examined food supplements, as some other molecules with a well known high antioxidant capacity are present in the analyzed food supplements
Reply to Early colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
No full textCrea il tuo bot-chimico telegram
No full textIn the digital age we live in, interactive learning has become a fundamental approach to engaging students effectively and stimulating their interest. Chemistry, with its complex formulas and molecular properties, can be a challenging subject for many students. However, recent advancements in artificial intelligence and the widespread availability of scientific data enable us to harness the potential of messaging bots to create innovative educational tools. A Telegram bot is a software application that operates within the Telegram messaging platform. Bots are designed to automate interactions and provide services to users through text-based chats. In the context of this project, the chemical bot on Telegram is developed with the aim of functioning as an interactive chemistry expert. Users can send questions and requests to the bot via chat, and the bot will respond by providing relevant chemical information. The educational significance of creating a Telegram bot extends beyond students specialized in computer science to include chemistry students. The process of developing a chemical bot involves acquiring cross-disciplinary skills that are valuable in various fields of study. By creating a bot, chemistry students can enhance their understanding of programming concepts and gain practical experience in integrating technology into their domain of study. This project provides a guide on creating a chemical bot using Python code executed on Google Colab. It explores how the bot utilizes the PubChemPy library to retrieve chemical information from the PubChem database. Users can interact with the bot, obtaining answers to basic questions such as retrieving the molecular mass of a compound based on its formula. Through the development of a chemical bot, students can develop critical thinking, problem-solving, and communication skills. Moreover, this innovative approach to studying chemistry fosters a deeper understanding of the subject matter and encourages active engagement with technology
New immunosensor for β-lactam antibiotics determination in river waste waters
No full textThe aim of the present research was to develop a single use, simple but highly sensitive amperometric immunosensor for penicillin G and other β-lactam antibiotics based on a “competitive assay”. The immunosensor developed uses an amperometric electrode for hydrogen peroxide as transducer and the peroxidase enzyme as marker. The results demonstrate the full validity of this immunosensor method which was optimized by comparing two different competitive operating formats. LOD was of the order of 10−10 M. The immunosensor developed displayed low selectivity toward all β-lactam antibiotics and higher selectivity toward other classes of non β-lactam antibiotics. In addition the Kaff value (about 108 M−1) was evaluated. Lastly, the immunosensor was used to test a β-lactam antibiotic “pool” and to recover penicillin G in common real matrices such as river waste water, obtaining good recoveries
Imparare la chimica analitica con il coding in Python
No full textThe innovation of teaching and learning methodologies in STEM (Science, Technology, Engineering, and Mathematics) is a priority for educational systems globally. It represents a fundamental challenge in schools to improve teaching effectiveness and the acquisition of technical, creative, digital, communication, collaboration, problem-solving, flexibility, adaptability, and critical thinking skills. Furthermore, the Ministry of Education aims to promote the establishment of laboratory spaces and the provision of suitable digital tools to support curriculum learning and the teaching of STEM subjects. The use of AI in STEM education opens new possibilities for engaging and interactive learning, fostering curiosity and exploration, and preparing students for the challenges of the digital age. This article presents a didactic approach to common problems in analytical chemistry, but also suitable for all STEM disciplines, which utilizes the foundations of the Python programming language to develop algorithms for solving various chemistry-related problems, including stoichiometry and analytical chemistry. Moreover, this educational program, divided into multiple modules, consists of laboratory sessions conducted in a computer or multimedia classroom. During these sessions, students will learn how to set up calculations and begin programming while gradually familiarizing themselves with the Python program’s commands and syntax. Among the codes developed so far by a group of students from ITIS Cannizzaro in Colleferro (Rome), there are a unit converter, a tool for calculating the pH of weak and strong acids and bases, a tool for calculating titration curves, and others currently under development such as Webapps. The utilization of AI in this approach brings numerous benefits, including personalized learning, adaptive feedback, data analysis for optimization, real-time assistance, and fostering curiosity and digital preparedness
NEW IMMUNOSENSOR METHOD FOR β-LACTAM ANTIBIOTICS DETERMINATION IN BOVINE MILK
No full textβ-lactam antibiotics are frequently used to prevent bacterial infections in humans and cattle. But improper use of β-lactam antibiotics can leave residues in cow milk and cause serious problems to human health. The intake of β-lactam antibiotics, which may be partly involuntary, since the food chain itself leads to its ingestion, or voluntary, in order to combat bacterial infections, more and more often causes bacterial resistance toward β-lactam antibiotics. It is also well known that the intake of β-lactam antibiotics can cause allergic potential in presensitized people. This is causing growing alarm among healthcare specialists as it can offset or prevent the use of one of the most important drugs ever discovered and produced by pharmaceutical chemistry. This explains the need felt for frequent, fast, simple and cheap tests that can be applied not only to human biological fluids but also performed directly in the cow’s milk and dairies produced and used directly in human food. Of course there is no lack of analytical methods to test for β-lactam antibiotics, such as penicillins and cephalosporins. Nevertheless the need for rapid tests with low LOD values has also encouraged the use of sensor, biosensor and immunosensor methods. In this context relatively sophisticated sensors have been developed [1-5]. The present article reports the our last research in this field, consisting in both the development of a competitive format ( see Figure 1) based on the BSA-Penicillin G conjugated immobilized on a polymeric active membrane, and the application of a new immunodevice to the analysis of real samples, such as of cow milk and urine. The new device uses an amperometric electrode for hydrogen peroxide as transducer, the BSA-Penicillin G immobilized on polymeric membrane overlapping the amperometric transducer and the peroxidase enzyme as marker. It proved to be highly sensitive, inexpensive and easily reproducible; LOD was of the order of 10-11 M. Lastly, the new immunosensor displayed low selectivity versus the entire class of β-lactam antibiotics and higher selectivity toward other classes of non β-lactam antibiotics. Good results were obtained by analysing samples of cow milk from healthy or sick animals, and satisfactory results were obtained in the recovery tests. The developed immunosensor method appears to afford a number of advantages in terms of simplicity, sensitivity, the possibility of “in situ” analysis and especially lower costs, compared with other existing more sophisticated devices or different chemical instrumental methods, owing to the fact that the immunosensor proposed by the authors is inexpensive; this is true even in the light of the fact that, to construct the present immunosensor, completely commercial components were used
NEW “COMPETITION FREE”, BUT NOT “LABEL FREE” IMMUNOSENSOR METHOD FOR THE DIRECT DETERMINATION OF IgG
No full textIn the last few years we fabricated several competitive immunosensors for the analysis of IgG proteins [1-4]. In the present study, to reduce the excessively long time required for each competition measurement, we developed an innovative “direct” immunosensor method for IgG determination. Of course other immunosensors for the direct measurement of several different antigens have already been described in the literature [5-7]; these devices usually do not involve any “competition” procedure and generally do not make use of a marker, because in these probes the signal is often obtained directly as a result of immunocomplex formation (which may, for example, be a cause of potential variation in the membrane). Usually these devices have not been very successful for various reasons (poor repeatability and scarce selectivity) even though they afford a considerable reduction in analysis time. Nevertheless, we recently resumed studies on direct immunosensors types as part of research conducted on new electrochemical immunosensors developed for the analysis of other proteins [8] and designed to perform a “competition free” measurement using different operating schemes. In the latter case, however, unlike what is usually reported in the literature for this kind of immunosensors (i.e. “Label Free” measurement), an enzymatic marker was again used to perform a “not Label Free” electrochemical measurement, while the transducer used was of the classic amperometric type [8]. In the present research slightly different approach was used for the measurement of IgG although of the same kind, while the electrochemical transducer was of the potentiometric type. The following conclusions may be drawn: direct amperometric immunosensor methods of this kind, in which no competitive step is thus envisaged, but which however still use an enzymatic marker, are as sufficiently precise, robust and reliable as the corresponding competition methods. Moreover, they have the additional advantage of taking half the analysis time and furthermore do not display the drawbacks of poor selectivity and precision often found in several direct potentiometric methods reported in literature, which do not use an enzymatic marker, as the signal is produced directly as a result of the antibody complex formation. Of course also the affinity constant value was evaluated, which resulted of the order of 107 M-1 . Lastly some applications to real matrices, i. e. human serum and milk, were performed using the new direct immunodevice. Results were compared with those obtained by applying, to the same samples, also a classical competitive immunosensor method previously developed by the present authors. Correlation between two immunosensor methods was satisfactory
AGENT ORANGE HERBICIDES, ORGANOPHOSPHATES AND TRIAZINIC PESTICIDES ANALYSIS USING NEW ORGANIC PHASE IMMUNOSENSORS
No full textThe determination of traces of pesticides in edible oils is an important problem. In
fact several kind of pesticides are scarcely soluble in aqueous solutions, in addition
also the oily matrix is practically insoluble in aqueous solvent, therefore the
quantitative determination of these species in oily matrices has always posed a
serious problem only partially solved by such techniques as gas chromatography,
which are more suitable when employed in a laboratory than in situ. A substantial
contribution to solving this problem was the development of Organic Phase
Enzyme Electrodes (OPEEs), i.e. enzymatic electrodes capable of operating in
organic solvents [1] and that can also act in situ. One classical example is that of
inhibition OPEEs [2] to analyse different types of pesticides that are relatively
insoluble in aqueous solution, in the development of which also our team was
recently involved [3]. The drawback consists in the fact that it is often complained
that inhibition biosensors are relatively unselective also versus pesticides belonging
to different phytopharmaceutical classes. Immunosensors, on the contrary, are the
most selective biosensors. However, in the last year we developed a new organic
phase Immuno Electrode (OPIE) [4]. Using this new device, applications were
developed first of all to detect triazinic pesticides in extra virgin olive oil, obtaining
good results [4]. Therefore new applications were recently developed using the
novel OPIEs to detect other herbicides and pesticides such as 2,4-D and 2,4,5-T
(i.e. agent orange herbicides), atrazine and simazine (triazinic pesticides) and
parathion (organophosphate pesticide) both in olive and in sunflower oil. The
working conditions were studied and optimized for new OPIE in the first previous
research on the triazinic analysis containing in extra virgin olive oil [4]. For the
analysis of the same pesticides in sunflowers oil, the only condition changed was
the use of 75% V/V n-hexane/chloroform mixture, which replaced the 50% V/V
mixture of the same solvents used in the previous research [4] and employed in the
competition step of the immunological method. This was because of the better
solubility of sunflower oil in the first mixture than in the latter. For all the
pesticides studied also the values of the affinity constant were estimated on the
basis of the value of the concentration at which half of the maximum response was
obtained. kaff were found to be of the order of 106
M-1 in all cases.
[1] J. Wang, Y. Lin, Q. Chen, Analyst, 1993, 118, 277-283.
[2] J. Wang, E. Demsey, A. Eremenko, and M. R. Smyth, Anal. Chim. Acta., 1993, 279,
203-208.
[3] L. Campanella, S. Eremin, D. Lelo. E. Martini, M. Tomassetti, Sens. Act. B, Chem.,
2011, 156, 501-515.
[4] M. Tomassetti, E. Martini, L. Campanella, Electroanalysis , 2012, 24(4), 842-856The determination of traces of pesticides in edible oils is an important problem. In
fact several kind of pesticides are scarcely soluble in aqueous solutions, in addition
also the oily matrix is practically insoluble in aqueous solvent, therefore the
quantitative determination of these species in oily matrices has always posed a
serious problem only partially solved by such techniques as gas chromatography,
which are more suitable when employed in a laboratory than in situ. A substantial
contribution to solving this problem was the development of Organic Phase
Enzyme Electrodes (OPEEs), i.e. enzymatic electrodes capable of operating in
organic solvents [1] and that can also act in situ. One classical example is that of
inhibition OPEEs [2] to analyse different types of pesticides that are relatively
insoluble in aqueous solution, in the development of which also our team was
recently involved [3]. The drawback consists in the fact that it is often complained
that inhibiti
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