Publications by authors named "Laura Pigani"

In this work, we investigated the ability of an electrochemical sensor to recognize Cannabis sativa L. samples with different total content of Δ-tetrahydrocannabinol (Δ-THC), determined by the levels of the psychoactive cannabinoid and of its biosynthetic precursor Δ-tetrahydrocannabinolic acid (Δ-THCA), using a multivariate approach. The voltammetric responses recorded with screen-printed electrodes modified with carbon black reflected the compositional differences from the different samples, in terms of cannabinoids of the vegetal material.

View Article and Find Full Text PDF

The sustainable industrial production of indigo necessitates a unique extraction process to separate the plant-derived compounds. Calcium compounds are added to encourage hydrolysis of these precursors and to facilitate the isolation of the final form, resulting in an organic-inorganic composite pigment with unspecified characteristics. In this study, we devised a continuous solvent extraction procedure to fractionate the organic indigoid phase within the composite pigment.

View Article and Find Full Text PDF

Two electrochemical sensors are proposed here for the first time for the fast screening of cannabinoids in L. plant material (inflorescences). The accurate control of cannabinoid content is important for discriminating between recreational, illegal, and fibre-type samples, which differ mainly according to the amount of Δ-tetrahydrocannabinol (Δ-THC) and Δ-tetrahydrocannabinolic acid (Δ-THCA).

View Article and Find Full Text PDF

Reusable Sonogel-Carbon electrodes containing carbon black (SNGC-CB) have been used for the electrochemical analysis of caffeic acid (CA) in real matrices. Measurements were firstly performed in standard solutions, in which SNGC-CB electrodes allowed the electrochemical determination of CA with high sensitivity and low limit of detection, equal to 0.76 μM.

View Article and Find Full Text PDF

Devices known as electronic noses (ENs), electronic tongues (ETs), and electronic eyes (EEs) have been developed in recent years in the in situ study of real matrices with little or no manipulation of the sample at all. The final goal could be the evaluation of overall quality parameters such as sensory features, indicated by the "smell", "taste", and "color" of the sample under investigation or in the quantitative detection of analytes. The output of these sensing systems can be analyzed using multivariate data analysis strategies to relate specific patterns in the signals with the required information.

View Article and Find Full Text PDF

Silica-based electrodes which permanently include a graphite/Au nanoparticles composite were tested for non-enzymatic detection of glucose and fructose. The composite material showed an effective electrocatalytic activity, to achieve the oxidation of the two analytes at quite low potential values and with good linearity. Reduced surface passivation was observed even in presence of organic species normally constituting real samples.

View Article and Find Full Text PDF

A glassy carbon electrode chemically modified with a carbon black coating is proposed here for the rapid and portable determination of cannabidiol (CBD) in a commercial Cannabis seed oil and in fibre-type Cannabis sativa L. leaves. The mechanism of CBD oxidation was studied in relation to simpler phenyl derivatives bearing the same electroactive group, namely resorcinol and 2-methylresorcinol.

View Article and Find Full Text PDF

The reactivity of the shortened salen-type ligands Hsalmp, Hsalmen and Hsal(-X)ben with variable -substituent on the central aromatic ring (X = Bu, Me, H, F, Cl, CF, NO) towards the trivalent metal ions manganese(III) and iron(III) is presented. The selective formation of the dinuclear complexes [M(μ-salmp)], M = Mn (), Fe (), [M(μ-salmen)(μ-OR))], R = Et, Me, H and M = Mn (-) or Fe (-), and (M(μ-sal[-X]ben)(μ-OMe)), X = Bu, Me, H, F, Cl, CF, NO and M = Mn (-) or Fe (-), could be identified by reaction of the Schiff bases with metal salts and the base NEt, and their characterization through elemental analysis, infrared spectroscopy, mass spectrometry and single-crystal X-ray diffraction of ·2AcOEt, ·2CHCN and ·2DMF was performed. In the case of iron(III) and Hsalmp, when using NaOH as a base instead of NEt, the dinuclear complexes [Fe(μ-salmp)(μ-OR)(salim)], R = Me, H (,) could be isolated and spectroscopically characterized, including the crystal structure of ·1.

View Article and Find Full Text PDF

The copper(ii) complexes of general formula [Cu(GL)(Cl)] (1-3, G = OMe, H and NO2, respectively), bearing tridentate Schiff base ligands (GL-) and a chloride as a fourth labile one, are here reported. The Schiff bases derive from the monocondensation of ethylenediamine and substituted salicylaldehyde, where the electronic properties are modulated by the releasing or withdrawing power of the G group. The compounds were structurally characterized through single crystal Synchrotron X-ray diffraction experiments in the solid state, revealing that 1 (OMe) and 2 (H) adopt a dimeric assembly [Cu(μ-Cl)(GL)]2 through apical interaction of the chloride ions of two monomeric units, while 3 embraces a 1D polymeric chain structure [Cu(μ-Cl)(NO2L)]n with a similar bridging fashion, all supported by extended intramolecular or intrachain hydrogen bonds.

View Article and Find Full Text PDF

Two A-π-D-π-A thiophene-based small molecules with a central dithienosilole core and dicyanovinyl (DCV) end groups were synthesized. These compounds differ only by the presence of alkyl and alkylsulfanyl chains, respectively, on the thiophene beta positions. Computational data together with the spectroscopic and electrochemical findings (obtained by means of absorption, steady-state/time-resolved emission techniques, and cyclic voltammetry) revealed that both molecules possess low electronic and optical band gaps, broad absorption spectra, and good stability both in p and n-doping states, which make them suitable for optoelectronic applications.

View Article and Find Full Text PDF

Two separate artificial sensors, an electronic eye (EE) and an electronic tongue (ET), were recently developed to monitor grape ripening based on the analysis of must. The aim of this research is to exploit the complementary information obtained by means of EE and ET sensing systems using different data fusion strategies, in order to develop an integrated device able to quickly and easily quantify the physico-chemical parameters that are used to assess phenolic ripeness. To this purpose, both low-level and mid-level data fusion approaches were investigated.

View Article and Find Full Text PDF

Poly(3,4-ethylenedioxythiophene)-modified electrodes have been used for the estimation of the polyphenolic content and of the colour index of different samples of wines. Synthetic wine solutions, prepared with different amount of oenocyanins, have been analysed spectrophotometrically and electrochemically in order to find a correlation between the total polyphenolic content or colour index and the current peak. The regression curves obtained have been used as external calibration lines for the analysis of several commercial wines, ranging from white to dark red wines.

View Article and Find Full Text PDF

The control of the noble metal concentration is crucial in order to increase the efficiency of hydrometallurgic processes in mining and in the recovery of precious materials from electronic waste. The present study is devoted to the development of an effective procedure for the quantification of Au(III) species dissolved in aqueous solutions, similar real complex matrices included. In particular, a novel electrode system based on Ti has been studied.

View Article and Find Full Text PDF

n instrument for the automatic quantification of glycerol in grapes has been developed. We verify here that this analyte can be used as a benchmark of a serious disease affecting the grapevines, namely Botrytis cinerea. The core of the instrument is an amperometric biosensor consisting of a disposable screen printed electrode, generating the analytical signal thanks to a bi-enzymatic process involving glycerol dehydrogenase and diaphorase.

View Article and Find Full Text PDF

A gold electrode partially coated by graphene multilayer is developed and tested with respect to high concentrations of hydrogen peroxide. The effective use of conventional electrode materials for the determination of such an analyte by anodic oxidation or cathodic reduction is prevented by the occurrence of adsorptions fouling the electrode surface. This prevents reliable and repeatable voltammetric curves for being recorded and serious problems arise in quantitative analysis via amperometry.

View Article and Find Full Text PDF

In this article the adsorption of 3-methylthiophene on planar and nanoparticle Au surfaces is investigated. The resulting systems are compared with a benchmark system based on 1-decanethiol. The characterization data collected evidence the formation of a packed 3-methylthiophene SAM on the planar surface.

View Article and Find Full Text PDF

The static dielectric constant of the [DMF(1) + ME(2) + DME(3)] ternary mixtures was measured as a function of temperature (25 < or = t/degrees C < or = 80) and composition, over the whole mole fraction range 0 < or = chi,chi2,chi3 < or = 1. The experimental values were processed by an empirical equation accounting for the dependence epsilon = epsilon(T, phi(i)), where phi(t) is the volume fraction of the components. A comparison between calculated and experimental data shows that this fitting relationship can be effectively employed to predict epsilon values in correspondence to experimental data gaps.

View Article and Find Full Text PDF

Measurements of the refractive index n for the binary mixtures 2-chloroethanol + 2-methoxyethanol in the 0 < or = t/degree C < or = 70 temperature range have been carried out with the purpose of checking the capability of empirical models to express physical quantity as a function of temperature and volume fraction, both separately and together, i.e., in a two independent variables expression.

View Article and Find Full Text PDF

A study on polythiophene coated microelectrodes is reported, the goal being that of checking the capability of these electrochemical systems to work in low conductive media. The possibility of electrochemically p-doping the polymer in the presence of very low concentrations or even in the absence of supporting electrolyte in the solution is ascertained, opening the way to the use of similar systems in pure solvent media. This result is obtained in such conditions that the presence of residual charges--and corresponding counterions--trapped inside the film coating can be reasonably hypothesised.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessionvqee04l56cjp4nf927rdds14snbca547): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once