Riccardo Angeloni

Further development on DMFC device used for analytical purpose: real applications in the pharmaceutical field and possible in biological fluids.

AbstractThe 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. Graphical abstractImipenem and Chloramphenicol determination using the DMFC and Ethanol determination using the enzymatic DMFC

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. The purpose was to establish a methodological approach consisting in the simultaneous application of different methods that it would be possible to use to obtain an accurate estimation of the total antioxidant capacity of different mixed berries and the food products containing them. Testing was therefore extended to also cover jams, yoghurts and juices containing mixed berries.

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 2.5 × 10−5 M.

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.

Study for developing an electronic tongue to discriminate three different classes of waters, by using common sensors and the principal component analysis

ABSTRACT 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.

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. It was therefore proposed a very simple innovative method, based on a catalytic fuel cell with the alcohol dehydrogenase enzyme immobilized in the anodic compartment of the device. The analytical performances of this new device were then evaluated by checking traces of alcohol in different types of natural waters (rain, river, and groundwater), with a good degree of precision and with an acceptable level of accuracy.

Alcohols Traces Checked in River and Rain Water Using a DMFC-Enzymatic Device

Using direct methanol fuel cell (DMFC) with alcohol dehydrogenase enzyme inserted in the anodic site by mean of a small dialysis bag, alcohol (ethanol and methanol) traces have been determined in rain and river natural waters. These two latter different type of natural waters have been also well distinguished using PCA and by performing additional measurements of pH, temperature, and oxygen content.

Chloramphenicol Determination by New Immunosensor Using Two Different Competitive Formats

In the present research has been performed the analysis of Chloramphenicol in bovine milk and rivers water samples, by a new immunosensor using two different competitive formats, one in which the antibody was immobilized on the membrane superimposed to the electrode, the other in which the antigen was immobilized on the membrane. In both cases satisfactory results were obtained, but from an analytical point of view the first format shown better features.

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

The 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.

Three Different Sensor Methods for Methanol and Ethanol Determination

Three different sensor-based methods for methanol and ethanol determination have been developed. Two of these consist of different enzyme electrodes using respectively alcohol oxidase or catalase immobilized in a k-Carrageenan gel layer overlapping an amperometric gaseous diffusion Clark type oxygen electrode. The third sensor is a small catalytic ‘fuel cell’ originally constructed for the purpose of obtaining energy from methanol or ethanol but now adapted for analytical purposes. The linearity ranges and LOD values for methanol and ethanol analysis obtained so far from three devices are optimized and compared.