Roberta Risoluti

Micro-solid phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry for the determination of stimulants, hallucinogens, ketamine and phencyclidine in oral fluids.

A confirmatory method for the determination of illicit drugs based on micro-solid phase extraction with modified tips, made of a functionalized fiberglass with apolar chains of octadecylsilane into monolithic structure, has been developed in this study. Drugs belonging to different chemical classes, such as amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, mescaline, phencyclidine and psilocybine were analyzed. The quantitation was performed by liquid chromatography-tandem mass spectrometry and the analytes were detected in positive ionization by means of an electrospray source. The limits of quantification ranged between 0.3 ng mL(-1) for cocaine and 4.9 ng mL(-1) for psilocybine, with coefficients of determination (r(2)) >0.99 for all the analytes as recommended in the guidelines of Society of Forensic Toxicologists-American Association Forensic Sciences.

Thermogravimetric characterization of dark chocolate

Dark chocolate is a complex food product in which sugar crystals and cocoa particles are surrounded by cocoa butter. Thermogravimetry and derivative thermogravimetry are proposed as fast, cheap, and sensitive tools to determine the composition of dark chocolate and consequently to confirm the cocoa percent declared by the producer or to check the production cycle.

Field detection capability of immunochemical assays during criminal investigations involving the use of TNT

The capability to collect timely information about the substances employed on-site at a crime scene is of fundamental importance during scientific investigations in crimes involving the use of explosives. TNT (2,4,6-trinitrotoluene) is one of the most employed explosives in the 20th century. Despite the growing use of improvised explosives, criminal use and access to TNT is not expected to decrease. Immunoassays are simple and selective analytical tests able to detect molecules and their immunoreactions can occur in portable formats for use on-site. This work demonstrates the application of three immunochemical assays capable of detecting TNT to typical forensic samples from experimental tests: an indirect competitive ELISA with chemiluminescent detection (CL-ELISA), a colorimetric lateral flow immunoassay (LFIA) based on colloidal gold nanoparticles label, and a chemiluminescent-LFIA (CL-LFIA). Under optimised working conditions, the LOD of the colorimetric LFIA and CL-LFIA were 1 μg mL(-1) and 0.05 μg mL(-1), respectively. The total analysis time for LFIAs was 15 min. ELISA proved to be a very effective laboratory approach, showing very good sensitivity (LOD of 0.4 ng mL(-1)) and good reproducibility (CV value about 7%). Samples tested included various materials involved in controlled explosions of improvised explosive devices (IEDs), as well as hand swabs collected after TNT handling tests. In the first group of tests, targets covered with six different materials (metal, plastic, cardboard, carpet fabric, wood and adhesive tape) were fixed on top of wooden poles (180 cm high). Samples of soil from the explosion area and different materials covering the targets were collected after each explosion and analysed. In the second group of tests, hand swabs were collected with and without hand washing after volunteers simulated the manipulation of small charges of TNT. The small amount of solution required for each assay allows for several analyses. Results of immunoassays confirmed that they were suitable to detect post-blast residues in soil and target materials and post transfer residues on hands, allowing further confirmation by more selective techniques. ELISA and LFIAs results obtained from the same solution were consistently in good agreement, and were confirmed by gas chromatography coupled to mass spectrometry (GC-MS). The reported immunoassays data demonstrates the suitability of LFIAs as on-site rapid and effective assays to detect TNT traces. The CL-ELISA proved useful in obtaining very sensitive detection in forensic investigations and testing, while CL-LFIA had performances in between LFIA and CL-ELISA.

Thermogravimetric analysis coupled with chemometrics as a powerful predictive tool for ß-thalassemia screening.

β-Thalassemia is a hemoglobin genetic disorder characterized by the absence or reduced β-globin chain synthesis, one of the constituents of the adult hemoglobin tetramer. In this study the possibility of using thermogravimetric analysis (TGA) followed by chemometrics as a new approach for β-thalassemia detection is proposed. Blood samples from patients with β-thalassemia were analyzed by the TG7 thermobalance and the resulting curves were compared to those typical of healthy individuals. Principal Component Analysis (PCA) was used to evaluate the correlation between the hematological parameters and the thermogravimetric results. The thermogravimetric profiles of blood samples from β-thalassemia patients were clearly distinct from those of healthy individuals as result of the different quantities of water content and corpuscular fraction. The hematological overview showed significant decreases in the values of red blood cell indices and an increase in red cell distribution width value in thalassemia subjects when compared with those of healthy subjects. The implementation of a predictive model based on Partial Least Square Discriminant Analysis (PLS-DA) for β-thalassemia diagnosis, was performed and validated. This model permitted the discrimination of anemic patients and healthy individuals and was able to detect thalassemia in clinically heterogeneous patients as in the presence of δβ-thalassemia and β-thalassemia combined with Hb Lepore. TGA and Chemometrics are capable of predicting ß-thalassemia syndromes using only a few microliters of blood without any pretreatment and with an hour of analysis time. A fast, rapid and cost-effective diagnostic tool for the β-thalassemia screening is proposed.

FTIR-evolved gas analysis in recent thermoanalytical investigations

ABSTRACT Several analytical instruments (like pyrolyzers, thermobalances, differential thermal analyzers, or calorimeters, and sometimes simply temperature-controlled reactors) can be on-line coupled to infrared spectrometers to perform evolved gas analysis (EGA). Advances in EGA techniques are currently proposed by the scientific literature because the possibility to on-line detect the nature of the released gases or vapors has become fundamental to proving a supposed reaction, either under isothermal or under heating conditions. In this review, recent analytical applications of evolved gas analysis performed by infrared spectroscopy (EGA-IR), selected among those published in the years 2013 to 2015, are collected.

New insights in forensic chemistry: NIR/Chemometrics analysis of toners for questioned documents examination

Near-Infrared spectroscopy (NIRs) coupled to chemometrics was investigated for the first time as a new tool for the analysis of black toners to evaluate its application in forensic cases. Ten black toners from four manufacturers were included in this study and the acquired spectra were compared in order to differentiate toners. Multivariate statistical analysis based on Principal Component Analysis (PCA) was considered to develop a model of comparison of toners in questioned documents. Results demonstrated the capabilities of the approach NIR/Chemometrics to correctly identify toners when printed on different papers and to be not affected by the printing process. This study has shown that NIRs can be considered as a useful, fast, non-destructive tool providing the characterisation of toners in forensic caseworks.

New frontiers in thermal analysis: A TG/Chemometrics approach for postmortem interval estimation in vitreous humor

The coupling of thermogravimetric analysis (TG) associated with chemometrics is proposed as an innovative approach in thanatochemistry in order to develop a new analytical tool using thermal analysis for the characterization of vitreous humor. Vitreous samples were selected from the medicolegal deaths which occurred in casualty and where the death interval is known. Only hospital deaths with no metabolic disorders were taken, and the precise time of death was certified by the treating physician. Samples were analyzed by TG7 thermobalance, and principal component analysis was used to evaluate the results. The TG/Chemometrics outcomes show a clearly distinct behavior according to the postmortem interval, concluding that TG and Chemometrics are capable of predicting the time since death using only a few microliters of vitreous, without any pretreatment and with an hour of analysis time.

Biomimetic complexes of Co(II), Mn(II), and Ni(II) with 2-propyl-4,5-imidazoledicarboxylic acid. EGA–MS characterization of the thermally induced decomposition

Solid complexes of Co(II), Mn(II), and Ni(II) with 2-propyl-4,5-imidazoledicarboxylic acid have been prepared and studied by means of mass spectrometry evolved gas analysis (EGA–MS). The applied hyphenated thermoanalytical approach has allowed description of the thermally induced decomposition steps and has supported the suggested mechanism. The results of this work in combination with the earlier reported data have suggested that two main thermally induced decomposition pathways are common of the imidazole-substituted complexes.

Biomimetic complexes of Cd(II), Mn(II), and Zn(II) with 2-aminomethylbenzimidazole. EGA/MS characterization of the thermally induced decomposition

Cadmium(II), manganese(II), and zinc(II) complexes with 2-aminomethylbenzimidazole have been synthesized following the reported procedures and characterized by mass spectrometry/evolved gas analysis (EGA/MS) to describe their thermally induced decomposition.

“Click” on PLGA-PEG and hyaluronic acid: Gaining access to anti-leishmanial pentamidine bioconjugates: Click conjugation of Pentamidine to PLGA-PEG and hyaluronic acid

Pentamidine (Pent), an antiparasitic drug used for the treatment of visceral leishmaniasis, has been modified with terminal azide groups and conjugated to two different polymer backbones (PLGA-PEG [PP] copolymer and hyaluronic acid [HA]) armed with alkyne end-groups. The conjugation has been performed by Copper Catalyzed Azido Alkyne Cycloaddition (CuAAC) using CuSO4 /sodium ascorbate as metal source. The novel PP-Pent and HA-Pent bioconjugates are proposed, respectively, as non-targeted and targeted drug delivery systems against Leishmania infections. Moreover, Pent has been encapsulated into PP nanoparticles by the oil-in-water emulsion method, with the aim to compare the biological activity of the bioconjugates with that of the classical drug-loaded delivery system that physically entraps the therapeutic agent. Biological assays against Leishmania infantum amastigote-infected macrophages and primary macrophages revealed that Pent, either covalently conjugated with polymers or loaded into polymeric nanoparticles, turned out to be more potent and less toxic than the free Pent.