The physico-chemical characterization, structure-pharmacokinetic and metabolism studies of new semi synthetic analogues of natural bile acids (BAs) drug candidates have been performed. Recent studies discovered a role of BAs as agonists of FXR and TGR5 receptor, thus opening new therapeutic target for the treatment of liver diseases or metabolic disorders. Up to twenty new semisynthetic analogues have been synthesized and studied in order to find promising novel drugs candidates. In order to define the BAs structure-activity relationship, their main physico-chemical properties (solubility, detergency, lipophilicity and affinity with serum albumin) have been measured with validated analytical methodologies. Their metabolism and biodistribution has been studied in “bile fistula rat”, model where each BA is acutely administered through duodenal and femoral infusion and bile collected at different time interval allowing to define the relationship between structure and intestinal absorption and hepatic uptake ,metabolism and systemic spill-over. One of the studied analogues, 6α-ethyl-3α7α-dihydroxy-5β-cholanic acid, analogue of CDCA (INT 747, Obeticholic Acid (OCA)), recently under approval for the treatment of cholestatic liver diseases, requires additional studies to ensure its safety and lack of toxicity when administered to patients with a strong liver impairment. For this purpose, CCl4 inhalation to rat causing hepatic decompensation (cirrhosis) animal model has been developed and used to define the difference of OCA biodistribution in respect to control animals trying to define whether peripheral tissues might be also exposed as a result of toxic plasma levels of OCA, evaluating also the endogenous BAs biodistribution. An accurate and sensitive HPLC-ES-MS/MS method is developed to identify and quantify all BAs in biological matrices (bile, plasma, urine, liver, kidney, intestinal content and tissue) for which a sample pretreatment have been optimized.

This thesis reports an integrated analytical and physicochemical approach for the study of natural substances and new drugs based on mass spectrometry techniques combined with liquid chromatography. In particular, Chapter 1 concerns the study of Berberine a natural substance with pharmacological activity for the treatment of hepatobiliary and intestinal diseases. The first part focused on the relationships between physicochemical properties, pharmacokinetics and metabolism of Berberine and its metabolites. For this purpose a sensitive HPLC-ES-MS/MS method have been developed, validated and used to determine these compounds during their physicochemical properties studies and plasma levels of berberine and its metabolites including berberrubine(M1), demethylenberberine(M3), and jatrorrhizine(M4) in humans. Data show that M1, could have an efficient intestinal absorption by passive diffusion due to a keto-enol tautomerism confirmed by NMR studies and its higher plasma concentration. In the second part of Chapter 1, a comparison between M1 and BBR in vivo biodistribution in rat has been studied. In Chapter 2 a new HPLC-ES-MS/MS method for the simultaneous determination and quantification of glucosinolates, as glucoraphanin, glucoerucin and sinigrin, and isothiocyanates, as sulforaphane and erucin, has developed and validated. This method has been used for the analysis of functional foods enriched with vegetable extracts. Chapter 3 focused on a physicochemical study of the interaction between the bile acid sequestrants used in the treatment of hypercholesterolemia including colesevelam and cholestyramine with obeticolic acid (OCA), potent agonist of nuclear receptor farnesoid X (FXR). In particular, a new experimental model for the determination of equilibrium binding isotherm was developed. Chapter 4 focused on methodological aspects of new hard ionization coupled with liquid chromatography (Direct-EI-UHPLC-MS) not yet commercially available and potentially useful for qualitative analysis and for “transparent” molecules to soft ionization techniques. This method was applied to the analysis of several steroid derivatives.

In this thesis the potential risks associated to the application of biochar in soil as well the stability of biochar were investigated. The study was focused on the potential risks arising from the occurrence of polycyclic aromatic hydrocarbons (PAHs) in biochar. An analytical method was developed for the determination of the 16 USEPA-PAHs in the original biochar and soil containing biochar. The method was successfully validated with a certified reference material for the soil matrix and compared with methods in use in other laboratories during a laboratory exercise within the EU-COST TD1107. The concentration of 16 USEPA-PAHs along with the 15 EU-PAHs, priority hazardous substances in food, was determined in a suite of currently available biochars for agricultural field applications derived from a variety of parent materials and pyrolysis conditions. Biochars analyzed contained the USEPA and some of the EU-PAHs at detectable levels ranging from 1.2 to 19 µg g-1. This method allowed investigating changes in PAH content and distribution in a four years study following biochar addition in soils in a vineyard (CNR-IBIMET). The results showed that biochar addition determined an increase of the amount of PAHs. However, the levels of PAHs in the soil remained within the maximum acceptable concentration for European countries. The vineyard soil performed by CNR-IBIMET was exploited to study the environmental stability of biochar and its impact on soil organic carbon. The stability of biochar was investigated by analytical pyrolysis (Py-GC-MS) and pyrolysis in the presence of hydrogen (HyPy). The findings showed that biochar amendment significantly influence soil stable carbon fraction concentration during the incubation period. Moreover, HyPy and Py-GC-MS were applied to biochars deriving from three different feedstock at two different pyrolysis temperatures. The results evidenced the influence of feedstock type and pyrolysis conditions on the degree of carbonisation.

This thesis describes the research focused on the study of different electrode supports modified with layered double hydroxides (LDHs) on Co or Ni as M(II) and Al or Fe as M(III) or conducting polymers for energy applications. The LDHs were characterized by electrochemical techniques, FE-SEM, XRD, XPS and XAS. Glassy carbon and Pt electrodes modified with electrosynthesized LDHs were employed in order to investigate their performances as oxygen evolution reaction catalysts and as pseudocapacitor materials. Moreover, the electrochemical synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) on indium tin oxide (ITO) was carried out in order to exploit an alternative route to fabricate bulk heterojunction solar cells with similar performances but less expensive than those obtained by casting. The photoactive layer was composed by [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) as electron acceptor, while as donor polymer it was employed either the commonly employed rr-poly(3-hexylthiophene) or a polythiophene copolymer, functionalized with a porphyrin derivative in order to improve the absorption in the UV/Vis region. In the second part of the thesis, the LDHs modified electrodes were employed for sensing, taking into account the electrocatalytic oxidation of sugars. Ni/Al or Ni/Fe LDHs were studied with the aim to investigate again the effect of Fe on the electrocatalysis. LDHs prepared both by chemical and electrochemical syntheses were employed with the aim of studying the effect of the order degree on the LDHs performance since this parameter is crucial to improve the “sensing” properties. Furthermore, a sensor for the amperometric detection of sugars in flow systems, based on Co/Al LDH electrosynthesized on Pt electrodes, was developed. A mixture of sugars was submitted to high performance anion chromatography with amperometric detection, using the modified electrode as the working electrode. Moreover, to assess the applicability of the device glucose, fructose, and sucrose content in real samples were successfully determined.

The activity carried out during my PhD was principally addressed to the development and characterization of new detection systems based on chemical luminescence (CL) for the implementation into smartphone based-biosensors for point of care (POC) and point of need applications. The aim of this research has been to determine the feasibility of combining smartphone detection capabilities with CL dependent assay results. In particular, my work has concerned the development of two smartphone-based assays to image and quantify chemiluminescence coupled biospecific enzymatic reactions to detect total cholesterol in serum and lactate in oral fluid and sweat. The devices were produced using a low-cost 3D printing technology and include a disposable analytical minicartridge, a mini dark box to avoid interference from ambient light measurement, and a holder to connect the dark box to a smartphone. The performances of these systems were compared with those obtained with a reference laboratory instrumentation (thermoelectrically cooled MZ-2PRO CCD camera). Finally, it was developed an alternative non-invasive smartphone-based assay to quantify lactate in oral fluid using a reagentless bioactive paper-based solid-phase biosensor integrated in smartphone-based device, employing light reflectance to measure an end-point enzymatic chemical reaction. The quantitative information is obtained from the change of color, due to variability of amount, intensity and brightness of light reflected from surface where assay has occurred. The proposed approaches based on the use of smartphone as detector paves the way for a new generation of analytical devices in the clinical diagnostic field. Moreover, the connectivity and data processing offered by smartphones can be exploited to perform analysis directly at home with simple procedures. The extreme simplicity of the device widens it applicability and makes it suitable for the detection of many analytes of clinical interest, for instance H2O2 producing all kind of oxidases.

In this dissertation thermal and catalytic pyrolysis of protein-rich biomass was investigated. The study was focused on the liquid and solid products. This thesis was aimed to gather chemical information on the thermal behavior of proteinaceous substrates in the presence of zeolite and compare with lignocellulosic biomass. Furthermore, the thesis was focused on the development of reliable analytical methods by means of Py-GC-MS in order to predicting bio-oil composition and to investigating biochar structure and its correlation with thermal stability. In addition a sampling procedure for the direct analysis of pyrolysis vapours based on absorption onto a microfiber (SPME) was developed. Py-GC-MS was applied as screening method to study the effect of different catalysts (H-ZSM5, MCM-41) and biomass-catalyst weight ratio on aromatic hydrocarbons production. The obtained results demonstrated that Py-GC-MS enable the selection of pyrolysis conditions. H-ZSM5 confirmed to be the catalyst with the best performance in terms of hydrocarbon production. In addition, the chemical composition observed by Py-GC-MS significantly reflects that obtained on bench scale. However, some difference has been found. Indeed, formation of high molecular weight PAHs have been observed only on bench scale and nitrogen-containing compounds and oxygenated compounds exhibited some difference related to condensation step. Problems during condensation step led to using SPME as at-line monitoring technique during the process capable of hot gas phase analysis. Strong similarity between GC-MS analysis of hot vapours and bio-oil from condensation traps were found. Finally, Py-GC-MS was applied to the chemical characterization of biochars obtained under different pyrolysis conditions or from different feedstock. Py-GC-MS can provide molecular indices useful to gather information on biochar thermal stability and to predicting the biochar carbonization degree. Furthermore, the molecular pattern resulting from Py-GC-MS could be utilized to infer information on the nature of the initial substrate and differentiate biochars.

No description available.

No description available.

No description available.

No description available.