31 research outputs found
The development of nano-structured printed electrochemical (bio)sensors for synergic approaches to environmental monitoring
No full textThe necessity to monitor the presence of toxic chemicals in the environment has become increasingly urgent during the last century. For this purpose, the emerging development of ad hoc designed electrochemical sensors for the selective and sensitive pollutants detection has attracted growing interest within the researchers’ attention. Indeed, it has been widely reported how the employment of electrochemical sensors allows for a reduction of the costs and the time required for the analysis with conventional techniques, as well as minimising the waste of reagents, resulting in a more environmentally-friendly approach. Basing on these features, electrochemical sensors play a noteworthy role within the scenario of environmental concerns, being particularly suitable for the planning of innovative and sustainable analytical monitoring programmes. Within the research work of my PhD studies, miniaturised electrochemical screen-printed sensors were developed, characterised and applied for the detection of two main categories of highly toxic and polluting chemicals: heavy metals and chemical warfare agents, which represent ones among the most worrying long-term threats for the environment and livings, because of their severe toxicity and
persistence in the environment. In order to tune the analytical performances of the herein developed sensors toward the detection of such substances, different nano-structured materials as well as different supports have been employed and combined with the versatile and cost-effective mass production of electrodes by using serigraphic and inkjet printing technologies. The overall approach of this research was focused on the development of synergic strategies to face environmental concerns. In detail, bismuth-based and Nafion-modified sensors, realised onto a flexible and transparent polyester support, were employed for the voltammetric detection of cadmium and lead ions in water
samples, as a more affordable and environmentally-friendly alternative to the conventional mercury based sensors. The electrochemical and analytical performances of these sensors upon storage and working conditions were evaluated, in order to improve the reliability of the heavy metal detection. In addition, such sensors were applied for the monitoring of heavy metal content in water environment, as well as biotic tissues, within remediation experiments carried out with filter-feeding organisms. In this way, the heavy metal uptake capability of the organism was examined and characterised, highlighting the high versatility and adaptability of the developed analytical tools for a variety of samples matrices. In a second part of the work, enzymatic inhibition paper-based sensors were realised for the detection of mustard agents, a class of toxic substances used as chemical weapons in the military field as well as in terrorist activities. The use of office and filter paper as support for serigraphic printing, coupled with the use of wax to realise hydrophobic patterns onto the paper sheets, allowed for the development of reagentless and wearable sensing tools for the real-time and on-site detection of this chemical risk. More precisely, the properties of paper were harnessed to integrate the reagents onto the sensor, as well as to allow for easy and safe disposal procedures of the sensors after the detection of these toxic chemicals (i.e. through incineration). The detection of mustard agents were performed by measuring their inhibitory activity toward choline oxidase enzyme, which was assessed through the amperometric measurement of the enzymatic by-product hydrogen peroxide. A Carbon Black/Prussian Blue nanocomposite was employed to enhance the electrochemical performances toward the reduction of hydrogen peroxide. Finally, another approach for the realisation of printed electrodes was investigated, by using inkjet printing technique and paper suitable for the realisation of electronic device as support with the aim to develop miniaturised fully-printed analytical devices, in which all the components, such as electroanalytical sensors, displays, and batteries, are integrated into the same support by printing. In detail, the electrochemical properties of a graphite-based inkjet-printed sensor were characterised by using ascorbic acid as a model analyte, and enhanced by the employment of Carbon Black nanoparticles as electrode modifier. These all-in-one devices pave the way for the improvement of the in-field applicability of printed electrochemical sensors, as well as for the decrease of costs, reagent consumption and waste material production
Heavy metal accumulation capacity of Axinella damicornis (Esper, 1794) (Porifera, Demospongiae): a tool for bioremediation of polluted seawaters
No full textA wide range of contaminants are continuously introduced into the aquatic environment and among these, heavy metals constitute one of the most dangerous groups because of their persistent nature, toxicity, tendency to accumulate in organisms and more still, they are non-degradable. Marine organisms such as sponges represent target species for the monitoring of heavy metal contamination due their filtering activity. This study aims to evaluate the retention capacity of lead and cadmium by the sponge Axinella damicornis under laboratory conditions. The sponges were exposed for 144 h to seawaters artificially polluted with lead (Pb) and cadmium (Cd) separately and with a mixture of the two metals. The final goal of the experiments was to evaluate the metal uptake in the sponge body and efficiency of the sponge in removing the metals from seawater. In particular, the highest values of metal concentration in the sponges were recorded for Pb: this metal was found to be 6 times and 9 times more concentrated than Cd, respectively in the case of exposure to the single metal and to the combination of both metals. The metal concentrations found, especially for Pb, were much higher in A. damicornis than in other organisms investigated in the sea. Remarkable signs of stress and necrosis were recorded in the specimens when exposed to the combination of Pb and Cd, evidencing a synergistic effect of the metals mixture. This study paves adds knowledge on the contamination effects by heavy metals on the marine organisms and on the contribution from A. damicornis as efficient tool for bioremediation of polluted seawaters
Smartphone-integrated electrochemical (bio) sensors as smart and reliable analytical tools
No full textSpeciation of Underivatized Organotin Compounds in Sediments by Gas Chromatography-triple Quadrupole Mass Spectrometry
No full textTributyltin is well recognized as an environmental endocrine disruptor and is listed as a priority substance that requires extended monitoring by the European Water Framework Directive (2000/60/EC). At the same time, due to their high pathogenicity, producing hormonal, immune, metabolic, and reproductive dysfunctions, other butyltin species (e.g. monobutyltin, dibutyltin, and tetrabutyltin) are consistently monitored in marine and freshwater aquatic ecosystems; the European Chemicals Agency classified these butyltin species as potential carcinogens and toxic substances for the human reproduction. Several analytical techniques, including gas chromatography and high-performance liquid chromatography, have been used to determine organotin species in aquatic ecosystems. Because of their chemical properties, organotin compounds are poorly stable upon temperature and are thus unsuited for direct analysis through capillary gas chromatography, which is usually performed after a derivatization step. The procedure described in this paper allowed the detection of underivatized chlorinated organotin compounds through gas chromatography-triple quadrupole mass spectrometry. Importantly, the obtained spectra of chlorinated monobutyltin and dibutyltin are herein presented and the fragmentation patterns are identified for the first time. The method was successfully applied to evaluate organotin compounds in sediments, providing the speciation of organotin species. Taking advantage of a simplified procedure of sample treatment, this study provided an innovative protocol for the gas chromatography/mass spectrometry of phenyl and butyl-substituted organotin compounds in contaminated sediments, capable of improving the efficiency of the conventional analysis of organotin compounds. © (2024), (Iranian Chemical Society). All rights reserved
Paper as smart support for bioreceptor immobilization in electrochemical paper-based devices
No full textThe use of paper as a smart support in the field of electrochemical sensors has been largely improved over the last 15 years, driven by its outstanding features such as foldability and porosity, which enable the design of reagent and equipment-free multi-analysis devices. Furthermore, the easy surface engineering of paper has been used to immobilize different bioreceptors, through physical adsorption, covalent bonding, and electrochemical poly-merization, boosting the fine customization of the analytical performances of paper-based biosensors. In this review, we focused on the strategies to engineer the surface of the paper for the immobilization of (bio)recog-nition elements (eg., enzymes, antibodies, DNA, molecularly imprinted polymers) with the overriding goal to develop accurate and reliable paper-based electrochemical biosensors. Furthermore, we highlighted how to take advantage of paper for designing smart configurations by integrating different analytical processes in an eco-designed analytical tool, starting from the immobilization of the (bio)receptor and the reagents, through a designed sample flow along the device, until the analyte detection
Paper-based devices as new smart analytical tools for sustainable detection of environmental pollutants
No full textThe use of paper as a multifunctional material in electrochemical sensing has been intensively explored over the
last decade. The combination among different kinds of paper as well as their coupling with different electro chemical cell configurations have been demonstrated, disclosing innovative sensing performances and features
that are still to be fully investigated. This ongoing research has found applications in a variety of fields, including
the biomedical, agri-food, security, and environmental ones, thanks to the high versatility and adaptability of the
paper material. In this review, we report a critical and comparative analysis of electrochemical devices based on
paper published within 2010–2021 and applied for the detection of pollutants of environmental interest in fresh
water, seawater, and other real environmental matrices. Several paper types, from common office paper to
Whatman filter paper with different filtering grades, were proved to be useful in this field. In detail, the
multifarious roles played by the paper are discussed, highlighting how the paper can be a suitable material for
electrochemical sensing while being capable of simplifying the measurement of complex real matrices or real izing programmable origami-like structures. Among the most important pollutants, a special focus is dedicated to
the emerging pollutants. Furthermore, the unique advantages achieved by the paper have been analyzed and
highlighted, reporting the future perspectives regarding the use of this surprising material
3D Sponge-Like Structures of Carbon Nanotubes for Heavy Metal Adsorption
No full textHerein, we investigate the synthesis and properties of carbon-based 3D
frameworks aimed at their application to Cd2+ and Pb2+ removal from the water
environment. The production of 3D sponge-like structures of nonfunctionalized carbon
nanotubes (CNTs) by chemical vapor deposition is described, with the morphological
and functional properties. After only a mild treatment in ethanol, their adsorption
capabilities toward heavy metals were studied using reference analytical methods to
disclose insights into the correlation between the structure and the adsorption efficiency.
Moreover, a 3D-printed portable and easy-to-use system was designed to apply the CNT
sponges to heavy metal removal in water, obtaining adsorption percentages of 15−48%
for Cd2+ and 45−82% for Pb2+ in tap water. Compared with other carbon-based
adsorbents, our strategy is competitive in removal efficiency while avoiding complex
treatments, demonstrating an inspiring strategy for promoting effective actions in water
remediation
Screen-printed electrode as a cost-effective and miniaturized analytical tool for corrosion monitoring of re-inforced concrete
No full textHerein, we report the first electrochemical sensor based on a screen-printed electrode designed to evaluate the corrosion level in iron-reinforced concrete specimens. The combination of an Ag pseudoreference electrode with a gel polymeric electrolyte allows for fast, stable and cost-effective potentiometric measurements, suitable for evaluating the corrosion of iron bars embedded in concrete samples. The sensor was found to be capable of discriminating between a standard non-corroded sample and samples subject to corrosion due to the presence of chloride or carbonate in the concrete matrix. The potential in concrete-based specimens containing carbonate (pH 9, - 0.35 +/- 0.03 V) or chloride (4% w/w, - 0.52 +/- 0.01 V) was found to be more negative than in a standard concrete-based sample ( - 0.251 +/- 0.003 V), in agreement with the ASTM standard C876 method which uses a classical Cu/CuSO4 solid reference electrode. Our results demonstrate that a printed Ag pseudoreference electrode combined with KC1 agar provides an efficient and reliable electrochemical system for evaluating the corrosion of iron bars embedded in concrete-based structures
An origami paper-based electrochemical biosensing platform for quality control of agri-food waste in the valorization strategy
No full textThe increasing demand for food and the need for a sustainability vision in the agri-food sector have boosted novel approaches for food management, enhancing the valorization of wastes and by-products belonging to the food industry. Herein, we present a novel paper-based origami device to assess the amount of both glucosinolate and glucose in a food waste product belonging to Brassicaceae plants, to evaluate the quality value and the correct management of waste samples. The device has been designed as an origami paper-based platform constituted of two paper-based biosensors to work synergistically in a multiplexed detection. In detail, a monoenzymatic biosensor and a bienzymatic biosensor were configured for the detection of glucose and glucosinolates, respectively, using filter paper pads preloaded with glucose oxidase and/or myrosinase. To complete the paper-based platform, the enzyme-preloaded pads were combined with office paper-based electrodes modified with Carbon black/Prussian Blue nanoparticles for the measurement of enzymatic by-product at a low applied potential (i.e., 0 V versus Ag/AgCl). Overall, this paper-based platform measured glucose and glucosinolate (i.e., sinigrin) with a linear range up to 2.5 and 1.5 mM, and detection limits of 0.05 and 0.07 mM, respectively. The repeatability corresponded to an RSD% equal to 5% by testing 10 mM of glucose, and 10% by testing 1 mM of sinigrin. The accuracy of the developed multiplex device was evaluated by recovery studies at two different levels of sinigrin, i.e., 0.25 and 0.5 mM, obtaining recoveries values equal to (111 ± 3) % and (86 ± 1) %, respectively. The multiplex detection of both glucose and glucosinolate in Brassicaceae samples evaluates the quality values of the waste sample, ensuring the quality of the re-used food product waste by using an eco-designed analytical tool. The combination of paper-based devices for quality control of food waste with the re-use of these food products represents a sustainable approach that perfectly matches sustainable agrifood practices as well as the overall approach of the circular economy. GRAPHICAL ABSTRACT: [Image: see text
Nuovi elettrodi stampati paper-based per il monitoraggio dei processi degradativi del cemento armato
No full textLA presente invenzione riguarda nuovi sensori “paper based”, questo termi-ne verrà chiarito di seguito, comprendenti almeno un elettrodo stampato su di un supporto flessibile scelto nel gruppo comprendente: poliestere, kapton, nylon, tedlar, mylar, carta da ufficio, carta cromatografica o carta da filtro; 5
per la misura della corrosione della barra metallica presente all’interno del-la struttura di cemento, del pH del cemento o dei cloruri contenuti nel cemento;
caratterizzati dal fatto che detti sensori comprendono almeno una parte in carta; in cui:
- detta parte in carta prima dell’uso deve essere inumidita; 10
- le misurazioni vengono effettuate su di un supporto solido (sul cement
