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Air pollution and the increasing production of greenhouse gases has prompted greater use of renewable energy sources; the EU has set a target that the use of green energy should be at 32 percent by 2030. With this in mind, in the last 10 years, the demand for pellets in Italy has more than doubled, making Italy the second largest consumer in Europe. The quality of the pellets burned in stoves is crucial to indoor and outdoor pollution. Among other parameters, moisture and ash are used to classify pellets according to EN ISO 17225:2014. This work involved the analysis of the organic and inorganic fraction of both some finished products on the Italian market and some raw materials (e.g., wood chips) sampled according to the technical standard EN 14778:2011. The analytical results showed the presence of some substances potentially harmful to human health such as formaldehyde, acetone, toluene and styrene for the organic fraction and nickel, lead and vanadium for the inorganic fraction. The chemometric approach showed that it is the inorganic fraction which is most responsible for the diversification of the samples under study. The detection of some substances may be a warning bell about the impact of such materials, both for the environment and for human health.

Sea salt can be considered as a vector of microplastics in the human body. In this work, the sea salts collected from three Italian salterns has been solubilized in MilliQ water and filtered to extract microplastics. The visual quantification of microplastics with a stereomicroscope was carried out on the bases of their size, followed by a classification taking into account their physical characteristics. ATR-FTIR and Raman spectroscopy were used to identify the polymeric type of microplastics. Their significant presence has been revealed: 1653 ± 29 microplastics/kg of sea salt. In total, 80.6 % of microplastics have a fiber shape, 18.9 % a fragmented shape and 2.7 % are sphere. The size of microplastics has been analysed, indicating that the most frequent is between 0 and 500 µm. Polypropylene, polyamide and polyethylene were identified as the most frequent types of polymers. This research could be of global relevance given the significant export of Italian salt to foreign countries., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In cultural heritage, unaesthetic stains on carbonate stones due to their close contacts with metals are of concern for the preservation of sculptures, monumental facades and archeological finds of various origin and antiquities. Rust stains made up of various oxidized iron compounds are the most frequent forms of alteration. The presence of ferric iron on rust-stained marble surfaces was confirmed in previous studies and oriented the choice of the best cleaning method (based on complexing agents specific for ferric ions). However, the composition of rust stains may vary along their extension. As the corrosion of the metallic iron proceeds, if the oxygen levels in the surroundings are low and there are no conditions to favor the oxidation, ferrous ions can also diffuse within the carbonate structure and form a variety of intermediate compounds. In this study, the iron stains on archeological marbles were compared with those artificially produced on Carrara marbles and Travertine samples. The use of integrated techniques (optical and scanning electron microscopy as well as Mössbauer and XPS spectroscopy) with complementary analytical depths, has provided the overall information. Rust formation and diffusion mechanisms in carbonates were revealed together with the evolution of iron speciation and identification of phases such as ferrihydrite, goethite, maghemite, nanomagnetite, and hematite.

Different plastic toys are on sale in the Italian market: they are sold as souvenirs and/or as toys. Such statuettes, called Gongoli, represent a famous character (a soccer player, a politician, the Pope, etc.). In particular, these products are widely sold, but the material composition is not sufficiently defined. Further, the effect of the release of dangerous compounds on human health is not sufficiently documented. Following this hypothesis, a study on eight different statuettes was carried out both for evaluating the possible presence of heavy metals and for evidencing their release from these objects. Preliminary analysis by means of EDS spectroscopy highlighted the percentage chemical composition of different products, especially the presence of total Cr and Ni. Release tests evidenced the release of Cr, Cu, Ni, and Pb: Pb reached 74 mg kg -1 , which is an interesting value even if it is lower than reported in the legislation. This study should be considered preliminary due to its limitations, such as the number of items investigated and the large variability found for some elements, but it highlights a serious problem related to the classification of these products which are marketed as souvenirs but manipulated by children.

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.

Research in restoration and conservation is directed vs. more sustainable working materials, methods and technologies. Electrophoretic removal, from porous material, of undesired stains due to charged species is theoretically an interesting alternative to chemical cleaning methods, but the lack of specific and comprehensive research work leads to controversial opinions about the efficiency and the needed harmfulness for the treated objects. In this work paper, samples with artificial rust stains were subjected to electrophoretic cleaning treatments in mineral water as electrolyte. Treatments were carried out either in a bath by complete sample immersion between the distanced electrodes or by sample wetting and sandwiching between the electrodes. Evaluation of cleaning efficiency and treatment effects was based on colour change measurements (image analysis of scanned paper samples before and after the treatment and by colorimetric data via spectrophotometric measurements), investigation of morphological changes by SEM observations and folding endurance measurements.

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.

Due to the bad state of conservation, "Palazzo Governi", a seventeenth-century building located in the old town district of "Stampace" in Cagliari (Sardinia, Italy), was subjected to restoration. Thus, according to the Italian Law n. 1089, the main façade colour must be reproduced, and therefore, its identification was required. The available samples looked fairly degraded, in particular as an easy plaster to crumble; so, some other analyses able to identify the degradation cause were performed. Two different approaches were adopted to attain the first goal, the visual colour assessment by a sensory panel (subjective) and the instrumental measurement by colorimetry (objective). Ion chromatography and inductively coupled plasma-optical emission spectroscopy analyses, as well as conductivity and pH measurements, were performed to evaluate the presence of water-soluble salts inside the plaster, as possible cause of degradation; the binder/aggregate ratio was also evaluated. A full mineralogical and petrographic characterisation of the materials constituting the samples, as well as the identification of their stratigraphy and some other morphologic and structural features suitable to highlight eventual forms of degradation, were performed by optical microscopy. Scanning electron microscopy coupled to X-ray microanalysis was been also used in order to confirm and/or to integrate data obtained by optical microscopy. The samples have been compared with two samples coming from two other buildings, also located in Sardinia, that looked in good conservation state. The results evidenced that the causes of degradation come from a high salt (especially sulphate) content and a scarce presence of binder in the plaster that can be imputed to a wrong initial composition and/ or to a leaching by acidic rain.

Roman hypogea, vernacular settlements or crypts, are underground places characterised by specific and unique challenges (RH<90% and almost constant temperature throughout the whole year) related to their relative isolation from the outdoor environment. These sites often require adequate monitoring tools providing complete environmental information in order to carry out appropriate strategies for scheduling routine maintenance and designing suitable layouts for their preservation. In this work we present the results of a carefully planned thermo-hygrometric monitoring campaign conducted in a peculiar Roman building (130CE), the "Casa di Diana" Mithraeum, sited in Ostia Antica (archaeological site, Rome-Italy), with the aim of characterising the indoor environment as the structure suffers of several conservation problems (biocolonisation, efflorescences, evaporating and condensing cycle for wall-building materials). The campaign involving multipoint continuous measurement was carefully planned to better describe this micro-clime. In addition to underground environmental data available in literature, we have also performed, as a checkpoint control, a thermo-hygrometric monitoring campaign in the "Terme di Mitra" Hypogeum, a few meters from the "Casa di Diana". The recorded data was analysed by multivariate statistical and chemometric analyses. The results brought to light the presence of different microclimates (three areas) within a single Mithraeum: a room (pre-Mithraeum) and an area (Mithraeum: 2-4m) present a thermo-hygrometric environmental behaviour in accordance with a semi-confined environment, another area (Mithraeum: 1-2m) behaves accordingly with underground environments (although it cannot be described as such), and the last area (Mithraeum: 0-1m) where was recording RH values close to saturation (96-99%), associated with non-ventilated areas where the rising damp is "held" and not dispersed, describing an own micro-clime, comparable to a "small greenhouse". This study has allowed to identify some critical areas in view of planning future conservation solutions, without exporting the artefacts kept inside., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: Drugs photostability plays two different opposite roles; a real advantage arises considering the longer expiration time of the drugs while the consequent persistence in the environment involves an obvious negative effect bound to their harmfulness.On this basis we tested the photostability and toxicity of three pharmaceutical active principles: Finasteride, Diclofenac and Naproxen. The pure active principles, as well as commercial drugs containing them, were considered; for the last, the protective effect of the packaging was also evaluated. Samples were irradiated according to the ICH Guidelines for photostability testing (The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use); a simulating sunlight source (a mercury-vapor lamp coupled to a tungsten filament one) was used to cover the wavelength range 300-2000 nm; Temperature, Relative Humidity, Irradiance and Illuminance were maintained constant during the photodegradation. The concentrations of the pharmaceutical active principles during the photodegradation were monitored by HPLC with UV/Vis detector. Toxicity tests were performed by means of an amperometric biosensor based on suspended yeast cells. Since the products obtained by the photodegradation process can result as toxic or more toxic than the original molecules, tests were performed first and after the photodegadation., Results: After 90 hours of exposure the concentration resulted lowered by 42.9%, 88.4% and 91% for Finasteride, Naproxen and Diclofenac respectively. Toxicity of the pure active principles follows the same order of the photostability. After photodegradation a contribute of the reaction products was evidenced., Conclusions: The simple and cheap analytical procedure here proposed, allowed to obtain not only data on photostability and toxicity of the pure active principles but, even if roughly, also useful information on the reactions kinetic and toxicity of the photodegradation products.

Background: This paper discusses results obtained in the second monitoring campaign of the Carcer Tullianum, a particular hypogeum environment located in the historical centre of Rome (Italy). In the first paper we stressed the need to apply chemometric tools to this kind of studies in order to obtain full and significant information; really information on sampling design, sensors (type, number, position) and instrument validation seems to be not easy to find in literature for researches dealing with monitoring of indoor environments.Also in this case three main parameters (temperature, humidity, illuminance) were monitored in the complex construction by an inexpensive self-assembled system along some horizontal and vertical vectors together with some measurements of oxygen, carbon dioxide and barometric pressure.With respect to the first campaign, we used a higher number of sensors to cover a new excavated zone; for the same reason, as well as to take into account the presence of visitors, a different experimental design was adopted., Results: Different data treatments were applied to data coming from all the used sensors. A good view of the microclimate was obtained that also resulted coherent with the different position of the three rooms constituting the monitored site (Carcer, Tullianum, Convent). Classical time plots resulted useful to evidence the correlation of the main monitored parameters (T, RH% and illuminance) with macroclimate, as well as their delay in following macroclimate. Box-Whisker and Gain-Loss graphs evidenced at the best the microclimate differences between the three rooms; an almost hypogean microclimate was evidenced for the lower room (Tullianum) where humidity values range between 90 and 100% while lower values, but anyway higher than the external, and spread more widely were measured passing to Convent and Carcer with minimum values around 50% for the last. A scarce or very scarce correlation with macroclimate was evidenced for all the three main measured parameters. Lighting results mainly dependent on artificial light and only in few cases, but unfortunately in the most precious zone, illuminance exceeds values suggested by Normative., Conclusions: Box-Whisker and Gain-Loss graphs allowed us to have the best view of the microclimate for all the monitored rooms. The influence of lighting by lamps on the other monitored parameters resulted overlapped and clearly topped the solar one. The worst situation was found in the Carcer, where the presence of the main chandelier worsens the state of the frescoed walls, already subjected to wide changes in temperature and humidity. Also the lighthouse located above the Convent provokes lighting exceeding values suggested by Normative while, as expected, LEDs resulted as suitable source of light from a conservation point of view.Susanne Heidi Plattner, Patrizia Fortini and Maria Pia Sammartino contributed equally to this work.

Background: Italian technical normative in the field of cultural heritage is often considered insufficient or not suitable in practise, therefore efforts are necessary to design new and/or improve already existing ones., Results: In this paper an alternative analytical procedure for the determination of water absorption (by full immersion) by stone material, described in the NORMAL 07-81 document, is proposed. Improvements concern methods accuracy and reduction of sample size; further also density data is obtained., Conclusions: The new procedure was applied on three different marble samples and outcomes are encouraging, but further testing is running to better understand to what extent sample size can be reduced without worsening accuracy of results, taking into account that stone is a very heterogeneous material.

Although it is well known that any material degrades faster when exposed to an aggressive environment as well as that "aggressive" cannot be univocally defined as depending also on the chemical-physical characteristics of material, few researches on the identification of the most significant parameters influencing the corrosion of metallic object are available.A series of ancient coins, coming from the archaeological excavation of Palazzo Valentini (Rome) were collected together with soils, both near and far from them, and then analysed using different analytical techniques looking for a correlation between the corrosion products covering the coins and the chemical-physical soil characteristics. The content of soluble salts in the water-bearing stratum and surfacing in the archaeological site, was also measured.The obtained results stress the influence of alkaline soils on formation of patina. Cerussite, probably due to the circulation of water in layers rich in marble and plaster fragments, was the main corrosion product identified by X-ray Diffraction (XRD). Copper, lead and vanadium were found in soil surrounding coins. By measuring conductivity, pH and soluble salts content of the washing solutions from both coins and soils, we could easily separate coins coming from different stratigraphic units of the site.Data were treated by cluster and multivariate analysis, revealing a correlation between part of the coins and the nearby soil samples.

Limestone basements holding bronzes or other copper alloys artefacts such as sculptures, decorations and dedicatory inscriptions are frequently met both in modern and ancient monuments. In outdoor conditions, such a combination implies the corrosion products of the copper based alloy, directly exposed to rainwater, will be drained off and migrate through the porous surfaces, forming stains of different colours and intensities, finally causing the limestone structures to deteriorate.In this work we have analysed samples from two modern limestone monuments in Rome, the Botticino surfaces of the 'Vittoriano' (by G.Sacconi, 1885-1911- Piazza Venezia) and the travertine basement of the 'Statua dello Studente' (by A.Cataldi, 1920- University city, La Sapienza), and focussed our investigation on the chemical composition of the copper-stained zones using XPS (X-ray Photoelectron Spectroscopy) as a surface-specific technique.Based on observations reporting on the structure and bonding at the calcite surfaces we have identified copper complexes and mixed calcium/copper carbonates associated with the stains, as well as the chemical state of other elements therein included, and related the compositional changes with differences in chromatic characteristics and sampling locations.

Too often microclimate studies in the field of cultural heritage are published without any or scarce information on sampling design, sensors (type, number, position) and instrument validation. Lacking of this fundamental information does not allow an open discussion in the scientific community. This work aims to be an invitation for a different approach.Three main parameters (temperature, humidity, luminance) were monitored in a selected part of a complex construction by an inexpensive self-assembled system along some horizontal and vertical vectors. All data was then processed and analyse by chemometric methods. Some measurements of oxygen, carbon monoxide and dioxide and pressure were also performed.Correlation of some indoor and outdoor data was shown for temperature and humidity. In case of outdoor changes the indoor environment reacted with a certain delay which is position-dependent and more evident for humidity data. The two observed rooms (Carcer and Tullianum) behave differently and the hypogean one is less influenced by the outdoor environment. Instrument validation before and after the campaign, allows to consider detected variations as significant.The fundamental importance of Sampling Design and of instrument validation before and after the monitoring campaign was enhanced. The choice of two main and two minor vectors allowed detection of different behaviour for the two rooms, also permitting to detect for both rooms a trend towards a spontaneous microclimate necessary for a conservation project. In the next campaign we will focus on the choice of the best sampling frequency to use more sophisticated statistical methods.

Trypanosoma brucei, the causative agent of human African trypanosomiasis, has a complex life cycle that includes multiple life cycle stages and metabolic changes as the parasite switches between insect vector and mammalian host. The parasite's single mitochondrion contains a unique catenated mitochondrial DNA network called kinetoplast DNA (kDNA) that is composed of minicircles and maxicircles. Long-standing uncertainty about the requirement of kDNA in bloodstream form (BF) T. brucei has recently eroded, with reports of posttranscriptional editing and subsequent translation of kDNA-encoded transcripts as essential processes for BF parasites. These studies suggest that kDNA and its faithful replication are indispensable for this life cycle stage. Here we demonstrate that three kDNA replication proteins (mitochondrial DNA polymerases IB, IC, and ID) are required for BF parasite viability. Silencing of each polymerase was lethal, resulting in kDNA loss, persistence of prereplication DNA monomers, and collapse of the mitochondrial membrane potential. These data demonstrate that kDNA replication is indeed crucial for BF T. brucei. The contributions of mitochondrial DNA polymerases IB, IC, and ID to BF parasite viability suggest that these and other kDNA replication proteins warrant further investigation as a new class of targets for the development of antitrypanosomal drugs.

Three different azodyes were used as target molecules to test the efficiency of the photodegradation process catalysed by titanium dioxide under UV irradiation. A comparison of different catalytic systems was performed using the catalyst both free in solution (system I) and immobilised in a polymeric membrane (system II). Iron oxalate and a conducting polymer (polyaniline, PA) were added to the I and II systems respectively to check an eventual synergetic effect. The research evolved through three different steps involving each one the use of a different analytical method. Shortly, the UV spectrophotometry were preliminarily used to monitor the bleaching process and allowed to choose the best catalytic system, HPLC and GC/MS were used to monitor the appearance and disappearance of the photodegradation intermediates and, lastly, the effective mineralisation was tested by an indirect ICP (Inductively Coupled Plasma) determination of the produced carbon dioxide.

Microwaves are used in medical applications, so their eventual toxicity effects must be carefully evaluated. An integral toxicity test, based on the monitoring of the respiratory activity of yeast cells, is proposed to evaluate the damage from microwave exposure. Different exposure times and microwave powers were considered. On supposing that the damages occur at enzymatic levels, the inhibiting effects of microwave exposure on two enzymes (glucose oxidase (GOD) and superoxide dismutase (SOD)), assumed like models as present in the human organism, was evaluated.

An immobilised Pseudomonas putida cell based biosensor, able to work directly in organic solvent (n-hexane), was designed and built. The response, in n-hexane, to benzene and some of its derivatives was studied. The proposed biosensor was found to be suitable for determining benzene in hydrophobic matrices.

An integral toxicity test, based on an algal biosensor and suitable to be used in sea water, is presented. The biosensor was designed and built by coupling a Clark oxygen electrode as transducer and the marine alga Spirulina subsalsa as biological mediator; it constitutes the "core" in a lab-scale prototype of a flow apparatus suitable to continuously monitor, in sea water, the photosynthetic activity of the alga and, from its variation, the marine pollution from the toxicological point of view. Inorganic pollutants (heavy metals) were tested in previous researches while organic ones (chlorophenols, pesticides and surfactants) are the object of the present paper.

An enzyme inhibition biosensor, developed in our laboratory and previously used for the analysis of compounds with anticholinesterase activity (e.g. physostigmine, neostigmine, pyridostigmine nicotine and organophosphorus compounds) has now been tested for the analysis of another recently synthesized cholinesterase inhibitor, i.e. eptastigmine. In addition nicotinic acid and nicotinamide, although displaying weaker inhibition properties, were also tested in pharmaceutical products using the same inhibition enzyme sensor. The biosensor consisted of a hydrogen peroxide amperometric electrode coupled to a functionalised nylon membrane chemically bonding both the enzymes butyrylcholinesterase and choline oxidase; a butyrylcholine standard solution in glycine buffer acted as substrate. The response of the system to all the inhibitors considered was characterised completely and the analysis of several pharmaceutical formulations containing nicotinamide or nicotinic acid was also performed.

The development and optimization of an analytical method using enzymatic biosensors able to operate in organic solvents [organic phase enzyme electrodes (OPEEs)] for the determination of the water content in food fats (butter, margarine) or pharmaceutical or cosmetic ointments is described. The method is based on the increase in enzymatic activity which is related to the increase in the percentage water content in the organic phase into which the biosensor is dipped. The enzymes used to assemble the biosensors were tyrosinase or catalase, the substrates were phenol or p-cresol and tert-butyl hydroperoxide, respectively, and the organic solvents were acetonitrile or dioxane. A gas diffusion amperometric electrode for oxygen measurement was used as electrochemical transducer. The results were compared with those obtained applying the Karl Fischer method to the same food or drug matrices. The correlations among the two methods proved satisfactory, as the difference in the computed values of water content was never higher than 7%. Also, the precision of measurements was acceptable (RSD < 6%) in all the analyses of real matrices.

An algal biosensor for toxicity assessment of estuarine waters is proposed. The sensor was obtained by coupling a suited algal bioreceptor (the cyanobacterium Spirulina subsalsa) to an amperometric gas diffusion electrode. The analytical device allows the monitoring of the evolution of photosynthetic O2 and the detection of alterations due to toxic effects caused by environmental pollutants present in the medium. Four chemical species representative of three main different classes of pollutants (heavy metals, triazinic herbicides, carbamate insecticides) were tested at different concentrations using a standardized natural water as experimental medium. In all the cases a toxic response was detected (i.e. a dose-related inhibition of photosynthetic activity was recorded) with good reproducibility.

The results reported in this paper regard the setting up of a polymeric membrane ISE that is selective for cholic acids (CA) and able to work in a flow system, especially in flow injection analysis (FIA), based on the exchanger (tetrakisdecylammoniumcholate, TDACh), which has proved effective, is of very simple but suitable structure and is above all easy to synthesise starting from commercially available chemicals. A complete analytical characterisation of the sensor was performed working both in batch conditions and in FIA, using in the latter case a 'wall jet' type of flow cell. The response toward different bile acid sodium salts such as the CA, deoxycholic (DCA), chenodeoxycholic (CDCA), ursodeoxycholic (UDCA), taurocholic (TCA) sodium salts was checked. The application to the analysis of different commercial drugs by FIA was also performed to determine the UDCA or CDCA acid content of several pharmaceutical formulations. Lastly, a preliminary study is presented concerning the use of the investigated electrochemical sensor as high performance liquid chromatography (HPLC) detector.

One of the first examples of a bienzymatic organic phase enzyme electrode (OPEE) is described. It was obtained using two enzymes (phospholipase D and choline oxidase), both immobilised in kappa-Carrageenan gel and, as electrochemical transducer, an amperometric gas diffusion electrode for oxygen. The response of the biosensor was recorded and its sensitivity, linearity range, response time evaluated. Lastly drugs and diet products containing lecithin were analysed using the new biosensor device working in an organic mixture.

The possibility of evaluating the content of hydrogen peroxide in several authentic matrices, such as cosmetic and pharmaceutical formulations, was studied. A new catalase biosensor fabricated using an amperometric gas-diffusion oxygen sensor as electrochemical transducer and the catalase enzyme immobilized in kappa-carrageenan gel and capable of operating in both aqueous and non aqueous solvents was developed and tested for this purpose. Creams, emulsions and disinfectant solutions were analysed. To this end, a preliminary check was needed to establish the best conditions to analyse these matrices; the choice of solvent was one of the most important points studied. The solvents considered included dioxane, water-dioxane mixtures, water saturated chloroform and aqueous solutions. The different solubility properties of the matrices analysed were taken into account.

Using three enzyme sensors (tyrosinase, catalase and glucose oxidase), capable of functioning also in non-aqueous solvents, we found new correlations between classical indicators, e.g. the log P value of several organic solvents and new empirical indicators such as ;maximum current variation' (MCV) and above all the ;current variation rate' (CVR), the values of which may be monitored with the biosensor considered dipping directly into the organic solvent. The trend of the immobilised specific activity of the tyrosinase enzyme dipping into different organic solvents was evaluated and compared with that determined by the spectrophotometric method. Lastly, an investigation was performed to experimentally verify the relation between hydrophobicity of the solvent and its ability to draw back the water from the enzyme microenvironment using the Karl Fischer method and thermogravimetric analysis to estimate the residual water in the enzyme microenvironment after having treated the enzyme with the organic solvent, then allowing it to dry.

A salicylate ISFET for the analysis of salicylic and acetylsalicylic acid in drugs is described. It is based on a salicylate ion selective membrane coated on the surface of the Si3N4 gate of the FET. The sensitive membrane consists of tetra-dodecylammonium salicylate, polyvinyl chloride and a proper plasticizer. The linearity range of the sensor is 5 x 10(-5)-1.5 x 10(-2) M for the salicylic acid, and 7 x 10(-5)-1.5 x 10(-2) M for the acetylsalicylic acid, respectively. The detection limit for the two compounds is 5 x 10(-5) M while the response time is < or = 20 s. The effect of pH and different interfering ions was also studied. The sensor was used to analyse the content of acetylsalicylic and salicylic acid in some drugs, and the accuracy of the method was evaluated through recovery tests. The results obtained with this method are well correlated either with those obtained with a classical ISE employing the same sensitive membrane or with the classical volumetric method.

A biosensor has been developed for the purpose of directly analysing aspartate in pharmaceutical formulations and aspartame in sweeteners. This biosensor consists of an ammonia-sensitive gas-diffusion electrode and the enzyme L-aspartase immobilized by means of polyazetidine on a dialysis membrane.

The main aim was to investigate the possibility of developing a fast, easily produced biosensor capable of being used in non-aqueous solvents such as n-hexane, chloroform, mixtures thereof and water-saturated chloroform. The research also provided an experimental confirmation of several concepts, described in the literature, concerning enzymatic activity in different types of non-aqueous solvents. The results are decidedly encouraging as regards future possible uses of this sensor to determine soluble substances in non-aqueous solvents.

The use of an enzyme tyrosinase sensor capable of being employed in non aqueous media represents a good opportunity to investigate the effects of the organic solvent on enzyme activity. Six different solvents are considered (n-heptane, n-hexane, n-pentane, toluene, chloroform, acetonitrile) and two properties of these solvents are studied in particular, i.e. hydrophobicity (as log P) and dielectric constant, taking into account their influence on sensor response. Results are generally in agreement with those found by other authors, who determined the behaviour of the enzyme activity as a function of organic solvents using different methods.

The relationship between dexamethasone-dependent changes in intracellular sphingosine levels, energy and phospholipid metabolism have been investigated by 31P-NMR spectroscopy and high-performance liquid chromatography. The cellular functions have been evaluated by cellular growth and immunoglobulin M secretion (IgM). Significant increases in intracellular phosphorylcholine (PCho), extracellular choline (Cho), and endogenous sphingosine levels were observed only at 30 min incubation with dexamethasone. These results confirmed a sphingosine-dependent hydrolysis of choline-linked phospholipids (Miccheli, A., Ricciolini, R., Piccolella, E., Delfini, M. and Conti, F. (1991) Biochim. Biophys. Acta 1093, 29-35). Furthermore, no significant variations were evidenced at hours 1, 2, 6 and 18 of incubation. Dexamethasone causes an inhibition of cellular growth and IgM secretion as well as the sphingosine treatment. The results suggest that the effect of dexamethasone may be mediated by endogenous sphingosine production in Epstein-Barr virus transformed B lymphocytes.

An ISFET device selective for cholanic acids, based on a PVC-sebacate membrane, containing benzyldimethylcetylammoniumcholate as exchanger, has been prepared, characterized and applied to the determination of cheno or ursodeoxycholic acid content of commercial pharmaceutical drugs and critical micellar concentration (CMC) values for cholate, deoxycholate and chenodeoxycholate. The results are compared with those obtained using previously described polymeric membrane sensors based on the same exchanger.

An enzyme-amperometric method is proposed for the analysis of total phenols and L-dopa; the method is based on the enzyme tyrosinase, which is immobilized in a Nylon membrane and coupled to an oxygen gas-diffusion amperometric electrode. The method was applied to the determination of total phenols in urine and to L-dopa in formulations and was evaluated as a promising alternative to currently adopted methods, e.g. to a classical spectrophotometric technique, chosen as a reference method.

The direct determination of chlorocresol in n-hexane extracts of commercial ointments was successfully performed using an enzyme-amperometric probe for analysis of phenols and working in previously characterized and optimized non-aqueous solvents. The analytical data obtained were compared with those found by using classical HPLC or chemical spectrophotometric method for determination of phenols.

Enzyme sensors for urea and creatinine were developed by coupling an ammonia gas-diffusion electrode with triacetate cellulose membranes entrapping urease or creatinine deiminase enzymes. Satisfactory results were obtained by using these sensors both in standard solutions and in authentic biological matrices.

The lecithin/sphingomyelin (L/S) ratio is particularly important for the prediction of foetal lung maturity. A package for pattern recognition of analytical chemical data, "Parvus", was used to handle the different values of the L/S ratio obtained experimentally by common amperometric, spectrometric and chromatographic methods for the determination of lecithin. Eight subjects were considered and some interesting conclusions drawn on the equivalence of different analytical methods of determining lecithin in amniotic fluid.

A new rapid and direct method for the determination of choline-containing phospholipids in the amniotic fluid is proposed. The determination is performed by an amperometric-enzymatic method. The correlation with an enzymatic-spectrophotometric method, already published, is also considered.