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Aims: A new basic research was conducted concerning the possibility of using a flow DCFC (Direct Catalytic Fuel Cell) for analytical purposes, checking ethanol and glucose. Also making considerations on the energy conversion aspect of these fuels. Background: There are a large number of studies concerning catalytic or microbial fuel cells, which allow to obtain electricity, both using liquid fuels, such as ethanol and methanol, or solid fuels, such as carbohydrates, biomass and so on. These systems are frequently characterized by high conversion efficiency but also high complexity and considerable costs. Objective: In the present research we investigated the possibility of using a very simple flow system to carry out measurement of ethanol concentration, or glucose analysis, using the same flow system associated with a small reactor containing yeast (Saccharomyces cerevisiae). Methods: The main operating conditions have been optimized and the concentration range where the flow system response shows a linear correlation with the fuel concentration was also identified. Result: The current delivered by the catalytic system operating in flow was determined and the calibration sensitivity values are higher than the sensitivity found in batch mode. It has also been shown that it is possible to realize a very simple system, which can be used to study and evaluate the conversion of chemical energy into electrical energy, using ethanol or glucose as fuel and the theoretical importance and analytical advantages have been emphasized, so that the use of carbohydrates, such as solid fuels, could represent. Conclusion: Present research has shown how, by operating in flow mode, rather than in batch, it is possible to have advantages from an analytical point of view, since a considerable increase in the sensitivity of the method can be obtained, probably attributable to a reduction in the effects of poisoning. Moreover, how it is possible to study and optimize the energy conversion conditions by means of a simple and inexpensive apparatus.

Electrical conductivity is one of the main parameters for the characterization of water solutions and for the monitoring of water sources. In this paper, we describe a very inexpensive prototype for conductivity measurements based on Arduino UNO R3 coupled to an open-source circuit board with only passive components. We designed the printed circuit board (PCB) and the suitable handmade cell using stainless-steel electrodes and wrote the freeware management software; the assembly of the prototype, including a temperature probe, and results were relatively simple. In order to allow for replicates, the instrument design, schematics, and software are available with an open-source license. Thirty-one bottles of spring waters with conductivities of between 15.2 and 2000 µS cm−1 were tested using both this prototype and a commercial conductivity meter. Data correlation produced an equation that allowed us to obtain the conductivity value, starting with the value furnished by the Arduino apparatus in arbitrary units. The prototype is accurate enough (inaccuracy lower than 6% excluding very low conductivity values) and precise (RSD% of about 5%). Even if a lot of commercial instruments for conductivity are available, we propose a prototype built with the aim of lowering the cost of measurements, while ensuring that they remain useful for lab or in situ application, as well as for continuous water monitoring/management systems. A further aim was to propose the building of the instrument as a laboratory exercise; this can help students to better understand basic theoretical concepts regarding conductivity, electronic components, and the acquisition and treatment of analytical data.

Background:: The possibility of estimating the age of fossil bones using only classic thermogravimetry, on the basis of proper % mass loss ratio values, has been widely considered in the past years. Objective:: Our research has brought some innovations to the previous background, by using chemometric methods and by processing the numerical files of whole thermogravimetric curves. The objective of this paper is the selection, among the main thermal analysis methods available, i.e., thermogravimetry (TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA) and thermal dilatometry analysis (TDA), of the most suitable one, in order to evaluate the age of fossil bones. Methods:: Fossil bone samples from two ancient cemeteries in Sudan were analyzed using different thermal methods (TG, DTG, DTA, and TDA). Data of whole recorded thermal curves have been processed by PCA analysis. Results:: A systematic comparison of several thermal analytical techniques allowed to conclude that TG or DTG curves can provide more appropriate information to determine how old fossil bones of different ages are, as evidenced by PCA processing of the entire file set of TG or DTG curves. Conclusion:: It can be concluded that the chemometric processing of TG or DTG curves data files is the best method; however, discussing other thermal analytical curves (DTA and TDA) can complete the information found by means of chemometric processing of whole TG and DTG curves.

Background: deep analytical study was performed on two different formats based on a “competitive” ELISA-type assay to develop a suitable, sensitive and cheap immune device for chloramphenicol determination that could be advantageously applied to the analysis of real matrices (pharmaceutical, food and environmental). Methods: To this purpose peroxidase enzyme as a marker and an amperometric electrode for hydrogen peroxide, as a transducer, were used. Through the first competitive format, chloramphenicol determination was based on the competition between chloramphenicol and conjugated with biotin-avidinperoxidase chloramphenicol, both free in solution, for anti-chloramphenicol immobilized in the membrane, while the second competitive format was based on the competition between free in solution chloramphenicol and immobilized in membrane one, for anti-chloramphenicol biotin-avidin-peroxidase conjugated free in solution. Results: The immunosensor was optimized by comparing the two used different “competitive” working formats on the basis of respective Kaff values, that were found to be about 105 and 104 (mol L-1)-1. The developed immune device displayed good selectivity for Chloramphenicol and LOD (limit of detection) was of the order of 10-9 mol L-1. The immunosensor was also used to test the presence of Chloramphenicol in real matrices such as cow milk, river wastewater and pharmaceutical formulations; recovery tests, using the standard addition method, gave satisfactory results. Conclusion: The results proved the validity of this immune device based on the competition between chloramphenicol and conjugated chloramphenicol obtained using biotin-avidin-peroxidase format, by which it is possible to carry out the analysis of chloramphenicol in milk and in river waste-waters with a % RSD ≤ 5 and with recovery values between 96% and 103%.

Background: In order to test real direct applicability for analytical purposes, a small and simple direct methanol (or ethanol) catalytic, enzymatic or non-enzymatic fuel cell (DMFC) was used for the analysis of ethanol-based pharmaceutical tinctures; a detailed experimental study was conducted on five different pharmaceutical tinctures available at drugstores. Results: The results obtained using both enzymatic and non-enzymatic devices were compared with those obtained by analyzing the same pharmaceutical samples with a conventional catalase biosensor. Finally, the results were compared with the nominal values provided by manufacturing firms. Conclusion: The correlations between the different experimental and nominal values considered were good in general or satisfactory and the applied statistical tests (f-test and t-test) were also very comforting. At the end of the study, the use of enzymatic DMFC proved to be better than non- enzymatic DMFC devices, because it requires shorter analysis times.

A new catalase amperometric biosensor for hydroperoxides detection has been built as part of research aimed at the development of biosensors based on layered double hydroxides (LDH) used as support for enzyme immobilization. The fabricated device differs from those developed so far, usually based on an LDH enzyme nanocomposite adsorbed on a glassy carbon (GC) electrode and cross-linked by glutaraldehyde, since it is based on an amperometric gas diffusion electrode (Clark type) instead of a GC electrode. The new biosensor, which still uses LDH synthesized by us and catalase enzyme, is robust and compact, shows a lower LOD (limit of detection) value and a linearity range shifted at lower concentrations than direct amperometric GC biosensor, but above all, it is not affected by turbidity or emulsions, or by the presence of possible soluble species, which are reduced to the cathode at the same redox potential. This made it possible to carry out accurate and efficient determination of H2O2 even in complex or cloudy real matrices, also containing very low concentrations of hydrogen peroxide, such as milk and cosmetic products, i.e., matrices that would have been impossible to analyze otherwise, using conventional biosensors based on a GC–LDH enzyme. An inaccuracy ≤ 7.7% for cosmetic samples and ≤8.0% for milk samples and a precision between 0.7 and 1.5 (as RSD%), according to cosmetic or milk samples analyzed, were achieved.

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.

An enzyme catalase biosensor was fabricated to determine hydrogen peroxide. The enzyme was cross-linked with [ZnIIAlIII (OH)2]+ NO3– Layered Double Hydroxide (LDH), which was glued on a glassy carbon (GC) electrode. The amperometric response to hydrogen peroxide was studied. A limit of detection (LOD) of about 0.20 mM and a good lifetime as high as 75 days were observed. A sensor with the same configuration, without the immobilized catalase enzyme and with LDH glued on (GC), was also realized. This non-enzymatic sensor also showed catalytic activity towards H2O2, exhibiting an amperometric response obviously much lower than that of the enzyme biosensor, with a LOD of about 1.0 mM. However, also the lifetime of this catalytic sensor was longer than 2 months after preparation.

Background: The investigation of human bones unearthed from necropolises is a useful tool to enhance our knowledge about ancient cultures. In the present study, the possibility of using the activation energy (EA) values of thermogravimetric degradation processes coupled with exploratory analysis methods in order to investigate human remains, has been tested. Methods: Several human bones from four distinct necropolises have been analyzed by thermogravimetry and then thirteen different approaches have been used to estimate their activation energy of the degradation processes of carbonate and collagen. The entire set of data has been analyzed by Principal Component Analysis (PCA) in order to draw some preliminary considerations over the remains. Results: PCA analysis highlighted the possibility of recognizing grouping tendencies related to the funeral ritual bodies underwent and/or their age. Additionally, in the second part of the work, where the focus is on the activation energies of collagen and carbonates degradation processes estimated by the method which was considered the most reliable (i.e., the Arrhenius formula with the third order decay), some tentative considerations about a trend in cremation temperatures are drawn. Conclusion: The estimation of values from thermogravimetric signals combined with chemometrics is a useful tool for the investigation of bone samples, which allow obtaining additional info about trends and/or grouping tendencies in complex systems as human remains.

In this communication first results are reported: seven organic molecules were considered: (3 alcohols) methanol, ethanol, propanol, (2 antibiotics) chloramphenicol, imipenem, (and 2 important biologic molecules) atropine and cortisone. For quantitative analysis seven different calibration curves were built (one for each molecule), showing different calibration sensitivity, which allows the quantitative determination of the seven organic molecules. For the qualitative analysis data from each of curves, obtained through the fuel cell, which represent the sensor’s response to each of the molecules considered, where processed by chemometric methods, so that it was possible to directly identify and recognize each of the seven organic molecules.

Analysis of rainwater in historical cities plays a key role to save ancient monuments from atmospheric agents. In this study we sampled the Rome’s rainwater from February to July of 2018 and we analysed them to determine their chemical and physical parameters: pH, redox potential, conductivity, temperature, and the concentration of the main inorganic ions (Na+, K+, Ca++, Mg++, F−, Cl−, NO3−, SO4−−). The volume of the daily fallen rainwater, the speed and direction of the wind in the sampling site were also collected. In order to find a correlation between all the above data we used the Principal Component Analysis (PCA). Results evidenced that there aren’t authentic “acid rains” as the minimum pH value that we found is 5.2. In some cases high concentrations of nitrates and sulphates were found with maximum values of 12.4 ppm and 18.7 ppm respectively. We also found no correlation between the rainwater’s composition and the seasonal period; on the contrary, the speed and direction of the wind, especially when coming from the sea or industrial country near Rome, play a noticeable role on the rainwater composition.

A basic research has been carried out using four probes to develop an electronic tongue able to discriminate three different kinds of natural waters, i.e. rain, river and groundwater. Several natural water samples were analysed to this purpose using a pH glass electrode, a digital (thermistor) thermometer, an amperometric gaseous diffusion oxygen sensor for measuring the dissolved oxygen and a direct methanol fuel cell enzymatic probe for measuring the concentration of alcoholic traces. Data were processed by means of principal component analysis, obtaining three well differentiated clusters, that demonstrate how the use of only four different sensors can discriminate in an inexpensive and effective way three different classes of natural waters.

This paper aims at investigating the possibility to use a catalytic “direct methanol fuel cell” (DMFC), previously optimized, for the analysis of chloramphenicol. The alcohol dehydrogenase enzyme was immobilized within it, for a direct analysis of the antibiotic. The analytical results confirmed the validity of this idea and highlighted the advantages, especially those associated with a remarkable decrease in the response time. A comparison with the use of the same device, but without the alcohol dehydrogenase enzyme (ADH), was made. The LOD was 8 × 10−7 M, while a 1.0–5.0 mM linear range was obtained in the presence of chloramphenicol. This also shows a high specificity for chloramphenicol. Finally, the main analytical data were compared and discussed with those obtained using a conventional amperometric immunosensor, assembled by us to this purpose, which uses a typical competitive format.

The present Special Issue is focused on developing and applying several sensors, biosensor devices, and actuators for the analysis of drugs, foods, and nutraceuticals. Some applications concern classical topics, such as clostridium determination in dairy products, flavouring material in foods like ethylvanillin, or the antioxidant properties of fruit juices, while other applications are more innovative, such as food safety analysis, artificial human senses (electronic nose, or tongue) development, or ethanol determination in pharmaceutical drugs, or forensic purposes using catalytic fuel cell; and lastly, new studies devoted to intelligent food packaging. Therefore, this Special Issue should interest both specialists in the sector and readers who are simply curious, or are simply interested in innovations in the field of food and drug analysis.

We carried out a preliminary study, using a Direct Catalytic Methanol (or Ethanol) Fuel Cell (DMFC) in association with yeast cells (Saccharomices Cerevisiae), both to evaluate the possibility of analytically determining glucose solutions of unknown concentration, and to determine the power (in μW) obtainable from a solution with a fixed glucose concentration. In this first research, after having experimentally verified the actual functioning of the system, we optimized the operating conditions, working at room temperature, such as the current intensity as a function of the yeast concentration in solution and the contact time between cells and glucose, carrying out the measurement in potentiostatic mode. It was therefore possible both to identify a short linearity range of the method for analytical applications and to evaluate the performance of this system from an energy perspective, using the experimental power curve. We lastly have also tried to obtain a short calibration curve, to be used for analytical purposes. Finally we also measured the current intensity obtainable using a weighed amount of glucose as fuel and estimated the power achieved from the system.

International audience; Near infrared spectroscopy and thermogravimetry have been coupled with chemometric exploratory methods in order to investigate ancient (pre-Roman/Roman) human bones from two different necropolises in Central-South Italy (Cavo degli Zucchi and Elea Velia). These findings have been investigated by principal component analysis and they have also been compared with ancient human bones from two Sudanese necropolises (Saggai and Geili). Samples coming from African and European necropolises, mainly differ in two aspects: the burial procedures and their historical period. The ritual applied in the European region involved cremation, while the one applied in the African necropolises did not. Bones from Italian sites (Cavo degli Zucchi and Elea Velia) are Pre-Roman/Roman while the others (from middle Nile) come from the Prehistoric, Meroitic, and Christian Sudanese age. Near infrared spectroscopy and thermogravimetric measures have been analysed either individually or by a mid-level data-fusion approach. Principal component analysis of the near infrared spectroscopy data allowed differentiation between burnt and unburnt samples, while from the scores plots extracted from the principal component analysis model based on the entire derived thermograms, it was possible to recognize the different clusters related to the various dating of samples. The data-fusion analysis led to considerations similar to those obtained from the model based on thermogravimetry data. Finally, instead of inspecting the entire thermogravimetry curves, principal component analysis was carried out on carbonates, total collagen and water losses only. In this case, the data-fusion approach has led to extremely interesting results; in fact, this model clearly shows that samples group in separate clusters in agreement with their age and the different burial rituals.

Recently proposed innovative methods for dating archaeological finds reported in the literature are reviewed, together with the researches carried out in this field by our team, using several instrumental techniques (sensor, biosensor, electrochemical, thermal-analytical, and so on). In this framework, particular attention was then focused on examining the main currently adopted methods for bones dating. Lastly, the possibility of using thermogravimetry coupled to chemometrics for differentiating, quickly and inexpensively, finds of very ancient human fossil bones (several thousand years BC), from less ancient ones (few hundreds of years before and after Christ) is illustrated, together with a thorough discussion of the criteria (i.e., the collagen-carbonates content ratio, or the different types of carbonate) this approach is based on.

The results of the simultaneous application of thermogravimetry and chemometrics, which allowed differentiating, quickly and inexpensively, finds of very ancient human fossil bones (~ 6000 BC), from less ancient ones (some hundreds of years before and after Christ) are here shown. The main purpose of the present research was to highlight if the selection of one or another anatomical part of a fossil skeleton could influence the differentiation of the antiquity of bone finds provided by the chemometric–thermogravimetric approach. The results obtained have shown that the variability related to the selection of one or another anatomical part of the skeleton is practically irrelevant, if compared to that related to the ancientness of the skeleton investigated.

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. Nevertheless the measurement time is much shorter and the measurement itself much easier to perform. Lastly several applications and recovery tests were carried out on bovine milk samples, before and after spiking, to check for triazine pesticides in the samples, obtaining satisfactory results.

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. 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.