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Electrochemical techniques have been successfully employed for the determination of two atypical antipsychotics, aripiprazole and octoclothepin, in pharmaceutical formulations and in biological fluids, with the aim to propose a method alternative to chromatography. We explored as well their electrochemical behavior and the use of DFT (Density Functional Theory) calculations substantially contributed to the rationalization of their electrochemistry. Thus, the mentioned compounds were analyzed in pharmaceutical forms by Linear Scan Voltammetry (LSV). A stripping voltammetric method (AdSV) was optimized for their determination in the μg L−1 range, concentration expected in biological samples such as urine.

This paper presents an overview of the recent applications of molecularly imprinted polymers (MIPs) to sample preparation. The review is thought to cover analytical procedures for extraction of contaminants (mainly illegal/noxious organic compounds) from food and environmental matrices, with a particular focus on the various pre-concentration/cleanup techniques, that is offline and online solid-phase extraction (SPE), dispersive SPE (d-SPE), magnetic SPE (MSPE), solid-phase microextraction (SPME) and stir-bar sorptive extraction (SBSE), applied before instrumental quantification. The selectivity and extraction efficiency of MIP-based sorbent phases are critically discussed, also in relation to the physical-chemical properties resulting from the synthetic procedures. A variety of molecularly imprinted sorbents is presented, including hybrid composites embedding carbon nanomaterials and ionic liquids. The analytical performance of MIP materials in sample preparation is commented as function of the complexity of the matrix, and it is compared to that exhibited by (commercial) aspecific and/or immunosorbent phases.

This is the first report on the photodegradation of ofloxacin under simulated solar light and in actual environmental matrices in the presence of a g-C

Mitoxantrone (MTX) is an antineoplastic agent whose use is limited by serious side effects on non-neoplastic cells. The aim of this study was the development of a new drug release system using an ionotropic gelation technique for microencapsulation of MTX in chitosan–carboxymethylinulin nanoparticles (CCInp), followed by evaluation of their cytotoxic effects on neoplastic MDA-MB-231 and non-neoplastic NIH3T3 cell lines. The CCInp were prepared through a new reliable method for easy functionalization of both inulin and chitosan. Both unloaded and drug-loaded nanoparticles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) and showed a spherical morphology with an average hydrodynamic diameter between 40 and 80 nm. Both nanoparticles were stable and easily degraded by lysozyme. MTX-loaded nanoparticles led to a greater mortality of MDA-MB-231 relative to free drug due to the ability of the nanoparticles to accumulate preferentially in neoplastic cells. The developed drug release system retains the ability to kill MDA-MB-231 cells in vitro, improving the survival of NIH3T3 cells.

The analytical application of silica-supported graphitic carbon nitride (g-C 3 N 4 @silica) for solid-phase extraction (SPE) of fluoroquinolone (FQ) pollutants from water is presented for the first time. g-C 3 N 4 @silica was easily and quickly prepared by one-pot thermal condensation of dicyandiamide and characterized by powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and surface area measurements. The novel composite was applied as sorbent for SPE of FQs from water prior high-performance liquid chromatography with fluorescence detection. The extraction efficiency of g-C 3 N 4 was tested in tap and surface waters at actual concentrations (10–100 ng L −1 ). Quantitative adsorption was achieved using 100 mg sorbent (20 wt% g-C 3 N 4 ) for pre-concentration of 50–500 mL sample, at the native pH (∼7.5–8). Elution was performed with 25 mM H 3 PO 4 aqueous solution-acetonitrile (80:20), obtaining recoveries in the range 70–114%, enrichment factors up to 500 and inter-day RSDs ≤ 12%. The batch-to-batch reproducibility was assessed on three independently synthesized g-C 3 N 4 @silica preparations (RSD 6–12%). g-C 3 N 4 supported on silica microparticles proved to be of easy preparation, inexpensive, reusable for at least 4 extractions of raw surface waters, and suitable for determination in real matrices.

The widespread presence of fluoroquinolone antibiotics (FQs) in natural ecosystems is a health hazard for humans and other living organisms. The role of sunlight in degrading FQs present in environmental waters has been studied. In particular, the photodegradation of four largely employed FQs, viz. Ciprofloxacin (CIP), Danofloxacin (DAN), Levofloxacin (LEV) and Moxifloxacin (MOX) has been studied in not tampered river water. Degradation rates have been investigated at ppb levels (20–50 μg L−1) under solar light, and the results have been commented critically. The products distribution has been studied by HPLC-ESI-MS/MS analysis and structures have been attributed on the basis of their mass fragmentation spectra. Importantly from the environmental point of view, the (potentially toxic) FQ nucleus remained intact over the early stages of the degradation. Indeed, the photoproducts were proved to possess residual antibacterial activity, as shown from in vitro antibacterial activity tests against different well characterized human and environmental bacterial strains, carried out on the above FQs, as well as for Enrofloxacin (ENR) and Marbofloxacin (MAR).

Among the neuroleptics, atypical antipsychotics have received great attention in recent years, because of their peculiar pharmacological profile. Due to their widespread use, rapid, efficient and economical methods of analysis of these compounds in pharmaceutical formulations and biological fluids are required, and in this sense electrochemical techniques appear particularly attractive. Most of these compounds are reported to be electroactive but quantification at classic electrodes is often unsuitable due to electrode fouling and absence or reduced linearity between concentration and current intensity. A gold electrode modified with oxidized single walled carbon nanotubes has proved useful to overcome these problems. A deep insight into the electrochemistry of these compounds is reported, with the aid of Mass Spectrometry and DFT (Density Functional Theory) calculation; in particular, a computational approach to the electrochemistry of these substances turned out to be really useful to the purpose. A voltammetric method for the determination of risperidone and olanzapine, two widely used atypical antipsychotics, has also been setup.

Here we describe the extraction from soil of the major photo-transformation products (PTPs) of enrofloxacin (ENR) and danofloxacin (DAN), two fluoroquinolones (FQs) widely used in veterinary medicine and of growing environmental concern, because their PTPs have been shown to retain high antibacterial activity. The microwave-assisted extraction (MAE) technique developed previously for determination of FQs, and based on use of an alkaline aqueous solution of Mg(2+) as a complexing agent for the analytes, was applied to agricultural soil samples fortified with different amounts of the PTPs and residues of the parent compounds (53-1000 ng g(-1) for ENR, 24-148 ng g(-1) for DAN). The PTPs, obtained by irradiation of thin layers of the two drugs, were, after extraction, separated and quantified by HPLC-FD. Good recovery (70-130%) and precision (RSDs 1-6% for repeatability and 9-22% for reproducibility) were obtained by use of the overall analytical procedure. The method was applied for the first time to study the in-soil lifecycle of ENR and DAN PTPs, generated in the matrix by irradiation under natural sunlight, at environmentally significant concentrations. Results indicated that soil-adsorbed FQ PTPs are themselves liable to photodegradation and have lifetimes comparable with those of parent compounds.

Borosilicate materials are of interest for many technological applications. Whereas sol-gel techniques are well suited for the preparation of these materials, the nominal concentration of boron is often not maintained, and a considerable amount of boron is lost during the preparation procedure. In this work we deal with the synthesis of borosilicate systems in order to analyse the problem of the boron loss. Different sol-gel precursors of B2O3 were explored and organically modified silicon alcoxide were tested, in addition P2O5 co-doping was proposed. IR spectroscopy, differential Scanning Calorimetry, Thermogravimetry and ICP-OES analyses were performed. Sol-gel synthesis of SiO2-B2O3 xerogels with a high boron content (>18 wt.%) was successfully obtained by employing trimethoxyboroxine and 3-aminopropyltriethoxysilane. (C) 2012 Elsevier B.V. All rights reserved.

The photodegradation of some among the most frequently prescribed fluoroquinolone antibacterials (FQs) was investigated in untreated river water under solar light as well as under the same conditions in the presence of suspended TiO2. The drugs considered included ciprofloxacin (CIP), danofloxacin (DAN), enrofloxacin (ENR), levofloxacin (LEV), marbofloxacin (MAR) and moxifloxacin (MOX), the last two belonging to the most recent FQ generation. The experiments were carried out in lab-scale batch reactor at concentrations (20–50 μg L−1) comparable to those actually measured in surface waters, and the course of the reaction was monitored by high pressure liquid chromatography (HPLC) with fluorescence detector (FD). A first order kinetics was obeyed upon both direct photolysis and TiO2 heterogeneous photocatalysis. The photoproduced intermediates were identified by HPLC with electrospray ionization tandem mass spectrometry (ESI-MS/MS) and the degradation paths were identified. It was concluded that direct irradiation caused fluorine substitution and reductive elimination, while photocatalysis caused oxidative degradation of the amine side-chain (most efficient with tertiary amines and five-membered cyclic amines). The latter one was a minor process upon direct photolysis and involved hydrogen abstraction by excited states or photoproduced radicals. Photocatalytic decomposition occurred at a rate from two to five times faster than direct photolysis for all of the drugs, except for CIP, that is roughly proportional to the amine oxidation potential. The kinetic constants ranged from 0.061 to 0.66 min−1 in direct photolysis, from 0.22 to 2.78 min−1 in the presence of TiO2. In the latter process, a 90% abatement of the concentration of these otherwise highly persistent drugs was obtained in ca. 15 min. This supports the contention that TiO2 photocatalysis under solar light is a convenient and efficient method for the remediation of pollutants at the μg L−1 levels despite the presence of other non-target matrix constituents. Noteworthy, TiO2 side-chain photo-oxidation was equally effective in the further degradation of the primary intermediates at a rate comparable to that of the parent compounds. The degradation proceeded further so that it could be expected that the antimicrobial activity, related to the FQ quinolone core more than to the substituent pattern, could be effectively eliminated.

An all-solid-state ISE for dopamine (DAHCl) has been developed based on a screen printed graphite electrode modified with a multiwalled carbon nanotubes layer as an ion to electron transducer. The selective membrane is an acrylic polymer molecularly imprinted with the ion of interest (MIP). The polymer is made up of methacrylic acid as functional monomer and ethyleneglycole dimethacrylate as cross linker. The polymerization at 75 °C in the presence of AIBN as initiator was carried out in situ, directly over the CNT-modified screen printed graphite. The specific site obtained after polymerization and template elution can be considered as the ionophore, and the carboxylic groups as the cation exchanger groups, similarly to the usual ISE membrane. The specificity of the electrode was evaluated by voltammetric methods, and was very good. The potential of the electrode, measured against a double junction Ag/AgCl/KCl (sat.), linearly increases with the dopamine concentration at concentration higher than 10−4 M, but only in salt solution at least 0.1 M. The sensibility was less than nernstian. Not any potential increase was found for the electrode modified with not imprinted polymer (NIP) at the same conditions. The effect of ions in solution was particularly considered.

Amino-terminated alkyl MWCNTs (MWCNTs-R-NH(2)), synthesized by chemical modification of the nanotube skeleton by nucleophilic substitution with 2,2'-(ethylenedioxy)diethylamine, were successfully used as stationary phases for gas chromatographic separation of esters and chloroaromatics. The presence of alkyl chains with polar embedded groups made the functionalized MWCNTs (f-MWCNTs) a mixed-mode GC separation material able to interact in different ways with the analytes. Compared with non-functionalized MWCNTs (nf-MWCNTs), MWCNTs-R-NH(2) had higher selectivity, enhanced resolution, and optimum retention behaviour, and they were proved to perform better than the commercial stationary phase Porapak QS (PQS), claimed to be suitable for similar applications. The so-prepared stationary phase was used for analysis of a synthetic mixture containing different classes of analytes, viz. esters, ketones, alcohols, alkanes, and aromatic hydrocarbons, and finally used for investigation of similar real matrices. In particular, the constituents of a commercial paint thinner were determined by direct injection of the sample, with good reproducibility (inter-day precision RSDs from 5 to 19%). Two unknown samples of commercial white spirit were also analysed for determination of the aromatic hydrocarbon content, and their composition was profiled on the basis of the different compounds identified.

Marbofloxacin (MAR) and Enrofloxacin (ENR), two largely employed veterinary Fluoroquinolones (FQs), were found to be present at the micrograms per kilogram level in agricultural soils of South Lombardy (Italy) several months after manuring. Distribution coefficients (K(d)) from sorption experiments indicated a strong binding to the soil. Soil samples fortified with environmentally significant FQs amounts (0.5 mg kg(-1)) were exposed to solar light that promoted extensive degradation (80%) of both drugs in 60-150 h. Thus, photochemistry could be considered a significant depollution path in the soil, although it was two orders of magnitudes slower than in aqueous solution and a fraction of the drug (ca. 20%) remained unaffected. For MAR the photoprocess was the same as in solution, and involved cleavage of the tetrahydrooxadiazine ring. On the contrary, with ENR only some of the photoproducts determined in water (those arising from a stepwise oxidation of the piperazine side chain) were observed. Substitution of the 6-fluoro by a hydroxyl group and reduction did not occur in the soil, supporting the previous contention that such processes required polar solvation of FQs. Consistently with this rationalization, the irradiation of thin layers of solid drugs led to essentially the same products distribution as in the soil. From the environmental point of view it is important to notice that photodegradation mainly affects the side-chains, while the fluoroquinolone ring, to which the biological effect is associated, is conserved up to the later stages of the degradation.

A gold electrode modified by chemisorption of Coenzyme A (CoA-CME) has been prepared. Exploiting its complexation properties towards heavy metal ions usually present in natural waters, it was shown that CoA has a stronger interaction with Cu than with the Pb and Cd; the complexation constants of bounded CoA with these ions were calculated by a novel approach. The metal ions can be determined in natural waters at the CoA-CME by open circuit preconcentration followed by medium exchange in citrate buffer before the anodic stripping voltammetry. The presence in solution of competing ligands and important aspects regarding the complexation were investigated.

We present a critical review of the analytical procedures proposed in the past decade for the determination of fluoroquinolones (FQs) by chromatographic methods in solid environmental matrices. We emphasize the overall analytical procedure, from sampling to final detection. We devote special attention to sample preparation, highlighting the problems involved in the analysis of real complex matrices, mainly soil, sediment, manure and sludge. We compare the different extraction techniques in terms of efficiency, time taken and environmental impact, pointing out advantages and drawbacks. We provide an overview on the role of photochemistry in the degradation of FQs in soils and sediments, and we underline the central position of analytical chemistry in environmental monitoring because FQs are emerging pollutants.

Linezolid belongs to a class of antibiotics known as oxazolidinones. It is receiving great attention due to its activity toward multidrugs resistant bacteria, and simple and cheap methods for the analysis of this compound in pharmaceutical preparations are required. In this work, the electrochemistry of the antibiotic linezolid was investigated and a differential pulse voltammetric method based on the oxidation of the oxazolidinonic compound at a glassy carbon electrode has been developed and optimized for its determination; LOD of 50 m gL � 1 and a linearity up to 200 mg L � 1 were reported. The electrochemical process was studied by using different electrochemical techniques

The preparation, characterization and analytical applications of gold electrodes modified with omega-mercapto alkyl/aryl sulfonates are described. The devices resulted effective for the determination of free and labile Pb(II) in water samples by anodic stripping voltammetry (E(dep) = -600 mV) and in particular 2-mercaptobenzimidazole-5-sulfonate (MBIS) offered the best performances with detection limit of 0.4 microg L(-1). Quantitative stripping of Pb from the electrode surface during the anodic scan, is obtained using sodium citrate buffer (pH = 9.0) as supporting electrolyte. Natural waters were analysed by standard addition method with good recoveries (mean percentage = 97%); no fouling effects due to humic acids or other organic constituents were observed in the reported conditions.

The preparation, characterization and analytical application of a chemically modified gold electrode (CME), based on thiolated α-cyclodextrin self assembled monolayer (SAM), have been described. The CME was effective for the determination of nitroaromatic explosive compounds; 2,4,6-trinitrotoluene (TNT) was determined with satisfactory results (LOQ = 30 μmolL−1). The analytical response in contaminated water and in presence of other nitroaromatic compounds, such as 2,4-dinitrotoluene (DNT) and picric acid (PA), has been evaluated.

The photochemical fate of Marbofloxacin (MAR) and Enrofloxacin (ENR), two Fluoroquinolones (FQs) largely used as veterinary bactericides known to be present in surface waters, was investigated in aqueous solution. The degradation of these pollutants (5-50 microg L(-1) starting concentration) was complete in about 1 h by exposure to solar light (summer) and obeyed a first-order kinetics. The structure of the primary photoproducts was determined. Those from ENR arose through three paths, namely, oxidative degradation of the piperazine side-chain, reductive defluorination, and fluorine solvolysis. More heavily degraded products that had been previously reported were rationalized as secondary photoproducts from the present ones. As for MAR, this underwent homolytic cleavage of the tetrahydrooxadiazine moiety to give two quinolinols. All of the primary products were themselves degraded in about 1 h. The photoreactions rates were scarcely affected by Ca(2+) (200 mg L(-1)), Mg(2+) (30 mg L(-1)), Cl(-) (30 mg L(-1)), and humic acid (1 mg L(-1)), but increased in the presence of phosphate (20 mg L(-1)). The fastest degradation of ENR occurred at pH about 8 where the zwitterionic form was present, while in the case of MAR the cationic form was the most reactive.

In the present work, we show a novel application of pristine and functionalized Multi-Walled Carbon Nanotubes (MWCNTs) as stationary phase in low-cost packed columns for the gas chromatographic separation of alkanes and aromatic hydrocarbons. The MWCNTs were deeply investigated by means of physical and chemical methods, like thermal analysis, IR and atomic force microscopy, and Inverse Gas Chromatography (IGC) in order to correlate the adsorption process and surface properties with the material purity level and functionalization degree. The derivatization process of the pristine nanotubes was a key factor to achieve a successful separation of both the light n-alkanes (C3-C5) and the related isomers (C4-C5 branched alkanes). Satisfactory results were similarly obtained in the case of separation of aromatic hydrocarbons (BTX).

Absence of gradients and Nernstian equilibrium stripping (AGNES) is a recently developed electroanalytical technique specifically designed for the direct determination of free concentrations of metal ions. AGNES is applied here to the determination of free Zn concentration in a river water sample. The method has been validated with synthetic solutions of low ionic strengths containing Zn and 2,6-pyridinedicarboxylic acid and then applied to synthetic river waters and to a natural sample collected from Besòs River in Montcada i Reixac (Catalonia, North-Eastern Spain). In the river sample, an average free Zn concentration of 12.8(4) nM was obtained, while the total dissolved Zn concentration was 0.51(8) microM. To control and maintain pH and pCO(2) constant during AGNES measurements, a novel device for N(2)/CO(2) mixed purging has been developed.

An investigation on filtration procedures and SPE sorbents used for the determination of traces of the most common veterinary fluoroquinolones (FQs), marbofloxacin (MAR) and enrofloxacin (ENR) used as antibacterial agents in cattle and swine farms in the province of Pavia (Italy), was performed in natural waters. The filter composition and the sorbent used in the SPE strongly influence the correct recovery, both in terms of total and dissolved FQs concentration. An accurate comparison among different filters and SPE sorbents showed that a full determination of analytes was possible on nylon filters followed by anionic (WAX) and hydrophilic-lipophilic balance (HLB) resins as SPE. Quantitative analysis was done by chromatography with fluorescence detection (HPLC-FD). Fluoroquinolones recovery was between 90 and 116% with RSD not greater than 10% (sample volume 250 mL). The developed method allowed to determine both dissolved and NOM-absorbed fractions of FQs, therefore a full determination of the analytes was possible. Limits of detection (LOD) and quantification (LOQ) were, respectively, 0.7 and 2.2 ng/L for ENR and 2 and 6 ng/L for MAR. The kinetics of degradation under solar light was explored.

Methylation of Lys residues on histone proteins is a well known and extensively characterized epigenetic mark. The recent discovery of lysine-specific demethylase 1 (LSD1) demonstrated that lysine methylation can be dynamically controlled. Among the histone demethylases so far identified, LSD1 has the unique feature of functioning through a flavin-dependent amine oxidation reaction. Data base analysis reveals that mammalian genomes contain a gene (AOF1, for amine-oxidase flavin-containing domain 1) that is homologous to the LSD1-coding gene. Here, we demonstrate that the protein encoded by AOF1 represents a second mammalian flavin-dependent histone demethylase, named LSD2. The new demethylase is strictly specific for mono- and dimethylated Lys4 of histone H3, recognizes a long stretch of the H3 N-terminal tail, senses the presence of additional epigenetic marks on the histone substrate, and is covalently inhibited by tranylcypromine. As opposed to LSD1, LSD2 does not form a biochemically stable complex with the C-terminal domain of the corepressor protein CoREST. Furthermore, LSD2 contains a CW-type zinc finger motif with potential zinc-binding sites that are not present in LSD1. We conclude that mammalian LSD2 represents a new flavin-dependent H3-Lys4 demethylase that features substrate specificity properties highly similar to those of LSD1 but is very likely to be part of chromatin-remodeling complexes that are distinct from those involving LSD1.

The photochemistry of 6-bromo-2-naphthols has been studied in acetonitrile, aqueous acetonitrile, and isopropyl alcohol in the absence and in the presence of triethylamine by product distribution analysis, laser flash photolysis (LFP), fluorescence, phosphorescence, electrochemical measurements, and DFT calculations. Hydrobromic acid loss in the presence of Et(3)N occurs from the triplet state of 6-bromo-2-naphthol, generating an electrophilic carbene intermediate, which has been successfully trapped by oxygen, allyltrimethylsilane, 2,3-dimethylbut-2-ene, pyrrole, acrylonitrile, 1,4-dimethoxybenzene, and also pyridine. The generation and the reactivity of a triplet carbene intermediate has been supported by LFP, with the detection of 2,6-naphthoquinone-O-oxide (530lambda650 nm) in the presence of O(2). The electrophilic diradical character of the carbene has been supported by DFT calculations, using the B3LYP, PBE0, and MPWB1K functionals, with the 6-31+G(d,p) basis set and PCM solvation model.

The lignicolous macrofungus Perenniporia fraxinea has drawn increased attention due to its role as a pathogen of ornamentals in urban sites. The present study investigated the bioaccumulation of heavy metals by P. fraxinea. Sporophores were collected from urban and suburban areas in Pavia (Northern Italy) and analyzed for metals content (Cd, Hg, Pb, Ni, Cr, Cu, Fe, Mn, Zn) by inductively coupled plasma mass spectrometer and inductively coupled plasma optical emission spectroscopy, after microwave acidic digestion. On the basis of the obtained results the potential bioaccumulation capability of P. fraxinea was investigated. The isolates were grown in a culture medium enriched with different concentrations of Cd and Hg, chosen as probes of environmental pollution, and Cu for comparison. As P. fraxinea grows in the presence of Cd, Hg and Cu, it seems to be a potential tool in environmental monitoring.

L-Carnitine (LC) in the preservation medium during storage of red blood cells (RBC) can improve the mean 24-hr percent recovery in vivo and increase RBC life-span after reinfusion. The purpose of the study was to investigate the differences in the biochemical properties of RBCs stored in the presence or absence of LC, and the cell-age related responses to storage conditions and to LC. RBC concentrates in saline-adenine-glucose-mannitol (SAG-M) were stored in the presence or absence of 5 mM LC at 4 degrees C for up to 8 weeks. RBC subpopulations of different densities were prepared by centrifugation on Stractan density gradient. Cells were sampled at 0, 3, 6, and 8 weeks, and hematological and cellular properties analyzed (MCV, MCHC, 4.1a/4.1b ratio as a cell age parameter, intracellular Na(+) and K(+)). After 6 weeks, MCV of RBC stored in the presence of LC was lower than that of controls (6 weeks MCV: controls 95.4 +/- 1.8 fl; LC 91.5 +/- 2.0 fl; n = 6; P < 0.005). This was due to swelling of control cells, and affected mainly older RBCs. LC appeared to reduce or retard cell swelling. Among the osmotically active substances whose changes during storage could contribute to cell swelling, only intracellular Na(+) and K(+) differed between stored control RBCs and LC-treated cells. LC reduces the swelling of older cells during storage at 4 degrees C in SAG-M, possibly by acting on the permeability of cell membrane to monovalent cations.

The determination of the post-mortem interval (PMI) of skeletal remains is a challenging aspect in the forensic field. Previous studies focused their attention on different macroscopic and morphological aspects but a thorough and complete evaluation of the potential of chemical and physical analyses in this field of research has not been performed. In addition to luminol test and Oxford histology index (OHI) reported in a recent paper, widely spread and accessible methods based on physical aspect and chemical characteristics of skeletal remains have been investigated as potential alternatives to dating by determination of

A chemically modified electrode (CME) on a gold surface assembled with a ω-phosphonic acid terminated thiol was investigated for its capability to complex uranyl ions. The electrode, characterized by electrochemical techniques, demonstrated to be effective for the determination of uranyl at sub-μgL(-1) level by differential pulse adsorptive stripping voltammetry (DPAdSV) in environmental waters, also in presence of humic matter and other potential chelating agents. The accuracy of the measurements was investigated employing as model probes ligands of different complexing capability (humic acids and EDTA).

The aim of this paper was to evaluate silicon (Si) concentration in human whole ventricular blood as a further potential chemical marker in the diagnosis of drowning. We employed an acidic digestion for the extraction of soluble Si, and an alkaline digestion for the determination of total Si, including particulate matter, both arising from drowning medium. 29 suspected drowning situations, 24 in fresh water (Fw) and 5 in seawater (Sw), were examined. The difference in Si concentration between the left and right ventricular blood (Si ΔL-R) was measured and alkaline Si ΔL-R seems, indeed, a potentially significant complementary tool in the diagnosis of Fw drowning, because insoluble silicon fraction does not undergo hemo-dilution or hemo-concentration, and the ΔL-R is not affected by exogenous factors. In spite of the limited number of cases investigated, a good correlation was observed between the analytical results and the macro-microscopic autoptic findings.

A novel, simple and straightforward method for determination of fluoroquinolones (FQs) in compost has been developed. The procedure entails a low-pressurized microwave-assisted extraction (MAE) carried out by a high performance instrument, in alkaline aqueous solution containing magnesium ions as FQs complexing agent, followed by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS). Ciprofloxacin (CIP), Enrofloxacin (ENR), Levofloxacin (LEV) and Norfloxacin (NOR), four widely used FQ antibiotics, were simultaneously extracted from compost by a single MAE cycle (20min, 135°C). The method was validated in terms of linearity, selectivity, sensitivity and accuracy. Quantitative absolute recovery (70-112%, n=3) and suitable precision (RSD

A chemically modified gold electrode has been conveniently prepared by binding multiwalled carbon nanotubes (MWCNTs) to which thiol functions have been tethered. The electrode has been characterized by atomic force microscopy and oxidative desorption experiments and gives excellent results for trace determination of As(III) and Bi(III) in natural and high-salinity waters, overcoming the limitation typical of solid electrodes. A mechanism for As(III) preconcentration at the electrode is proposed and supported by results obtained by two similar chemically modified electrodes (CMEs), the first one prepared with single-walled carbon nanotubes and the second one with a monolayer of (biphenyl)dimethanethiol. The performance obtained with the MWCNTs-CME largely overcomes that obtained by using other devices.

d , l -Penicillamine and thiodimethylglyoxime (TDMG) self-assembled monolayers (SAMs) on gold electrode were prepared and characterized by electrochemical measurements. The two sensors exhibit sensitive and selective response to Cu(II), both forming 2:1 complexes, the first one in acetic buffer and the second one in ammonia buffer. Copper determination at trace level (LOQ 0.2 and 0.3 μg/L for d , l -penicillamine and TDMG, respectively) is possible with both the electrodes as verified in tap, spring and sea water. The influence on copper determination of most common ions present in natural waters and of organic matter has been investigated. Accuracy was checked by recovery test on spiked samples.

Lichens as biomonitors and neutron activation analysis as analytical technique have been employed to evaluate the trace element atmospheric pollution in the metropolitan area of the city of Pavia (Northern Italy). Transplanted lichens (Parmelia sulcata and Usnea gr. hirta) and air particulate matter have been monthly collected and analyzed during the winter 2001-2002. INAA and ET-AAS have been used for the determination of 28 elements in air particulate matter and 25 elements in lichens. Trace metals concentrations as well as the corresponding enrichment factors were evaluated and compared.

Trace element (TE) characterization and analysis in epiphytic lichens collected in different areas of the Himalayas (Nepal) and of the Alps (Italy) is presented. The results give information for the assessment of TE distribution present in the two different areas. The evaluation of the enrichment factors may provide information for many elements about their association to long-distance atmospheric transport phenomena. To this purpose, samples of superficial soils, collected in the same areas of those of the lichens, have also been analyzed. Most of the trace elements were determined by instrumental neutron activation analysis (INAA), while lead and cadmium measurements were carried out with electrothermal atomic absorption spectroscopy (ET-AAS).

The Mycobacterium tuberculosis genome encodes two ferric uptake regulator homologues, furA and furB, the function of which is under investigation. Using Mycobacterium smegmatis as a model system, we investigated the transcriptional pattern of Rv(Ms)2358-furB genes. Transcripts covering the two genes could be identified by northern blotting and by reverse transcriptase PCR. The transcriptional start point was mapped at one base upstream of the Ms2358 start codon by the RACE technique. By cloning M. smegmatis and M. tuberculosis DNA regions upstream of a reporter gene, we demonstrated the presence of one promoter, located immediately upstream of the Rv(Ms)2358 gene. Promoter induction was tested on several cultures grown under different conditions of pH and temperature, and in the presence of different concentrations of metallic ions. The promoter was found to be specifically induced by zinc. The recombinant M. tuberculosis FurB protein typically contained two zinc ions per protein monomer. Complete removal of zinc could not be obtained, even with strong denaturation treatment. Our data are in favour of the hypothesis that Rv2358 and FurB are transcriptional regulators involved in zinc homeostasis.

A new procedure is presented for the determination of the ligands of copper(II) in natural waters, based on titration with the metal ion, monitored by measuring the concentration of copper(II) sorb...

A speciation method of inorganic nickel compounds in airborne particulate, based on selective sequential extractions, is described. It allows the separation and the determination of Ni(0), Ni(II) soluble salts such as sulphate and chloride, Ni insoluble compounds such as nickel oxide and sulphide, to which a different toxicity and therefore a different risk are related. The nickel concentration in each fraction was determined by Flame or Furnace Atomic Absorption Spectroscopy. The proposed procedure has been tested first, on synthetic samples prepared with the different nickel compounds, in the presence of atmospherical particulate matter not containing nickel, in order to take into account the possible matrix influence. The speciation was then repeated on four different samples (fly ash deriving from a solid waste incinerator and three RSMS from NIST: Coal Fly ash SRM 1633b, Urban Particulate 1648, Washington Dust 1649), followed by an evaluation of matrix spiking and recovery analyses. Performing multiple analyses of the spiked samples assessed the repeatability of the procedure.

The detection and investigation of metal ions bound in strong complexes in natural waters is a difficult task, due to low concentration of the metal ions themselves, and also of the strong ligands, which, moreover, are often not of a well-defined composition. Here, a method is proposed for the investigation of the speciation of metal ions in natural waters.It is based on the sorption of metal ions on strongly sorbing ion exchange resins, i.e. complexing resins. For this reason the method is called Resin Titration. It has been shown in previous investigations that the concentration of metal ion totally sorbed by a particular resin, and its reaction coefficient in the solution phase in the presence of the resin, can be determined from the sorption data using a simple relationship. Here, a data treatment (the Ruzic linearization method) is proposed for also determining the concentration of the ligands responsible for the complex in equilibrium with the resin.The method was applied to data obtained by Resin Titration of a freshwater and a seawater. Copper(II) and aluminium(III) were considered, using Chelex 100 as a titrant, due to its strong sorbing properties towards these metal ions. The results were: the total metal concentration in equilibrium with the resin, the side reaction coefficients, and the concentration of ligands. In all these cases the ligands forming very strong complexes were found to be at concentration lower than that of the metals.The Ruzic linearization method allows the determination of the concentration of the ligands forming very strong complexes in equilibrium with Chelex 100. The reaction coefficient was better determined by the calculation method previously proposed for RT. The ligands responsible for the strong complexes were found to be at low concentration, often lower than that of the metal ions considered. The metal in the original sample is partly bound to these ligands, since the complexes are very strong. Only a part of the metal is linked to weaker ligands, or free.

A thermal treatment at 900°C (under nitrogen) of a milled mixture MnO-Fe2O3 yields MnFe2O4 mainly as the product of the reaction between Mn3O4 (produced by ball milling) and Fe2O3. Under the same experimental conditions but starting from an unmilled MnO- Fe2O3 mixture, the formation of MnFe2O4 is only partial and occurs through Mn3O4 (formed by oxidation of MnO). The same thermal treatment (900°C under nitrogen) of a milled Mn3O4-Fe2O3 mixture yields MnFe2O4 mainly as the product of the reaction between Mn3O4 and Mn2O3/MnO2 (the higher Mn oxides being produced by ball milling) and Fe2O3. The effect of high energy milling is more pronounced in the case of the Mn3O4-Fe2O3 system since no MnFe2O4 formation is observed when starting from a physical mixture.

The photodegradation of Ciprofloxacin (CIP), Enrofloxacin (ENR), Danofloxacin (DAN), Marbofloxacin (MAR) and Levofloxacin (LEV), five widely used fluoroquinolones (FQs), was studied in urban WWTP secondary effluent, under solar light. The degradation profiles and the kinetic constants were determined at the micrograms per litre levels (20–50 μg L−1). The photo-generated products were identified by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC–ESI-MS/MS). The toxicity of the photoproducts was assessed by Vibrio fischeri light emission inhibition assay performed on irradiated and not-irradiated FQs solutions, at environmentally significant concentrations. Attention was focused on the evaluation of the photoproducts contribution to the overall biotoxic effect of these emerging pollutants. Data from chronic exposure experiments (24–48 h) were primarily considered. Results confirmed the major usefulness of chronic toxicity data with respect to the acute assay ones and proved the not negligible biotoxicity of the FQs photodegradation products.

a b s t r a c t This work presents a novel analytical method based on graphene for the determination of five widely used fluoroquinolones (FQs) in aqueous matrices. The procedure entails solid-phase extraction (SPE) on graphene-derivatized silica (200 mg), followed by liquid chromatography with fluorescence detection. Monolayer graphene oxide (GO) flakes were covalently bonded onto aminopropyl silica microparticles, and then treated with aqueous hydrazine to obtain the reduced GO (RGO). The final material (RGO–silica) was characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and BET analysis, and for the first time evaluated as mixed-mode sorbent for the SPE of FQs from natural waters. Accuracy was studied on tap/raw river water in the concentration range 5–10,000 ng L −1 , obtaining mean absolute recoveries from 72 to 118%. The inter-day precision was good, showing relative standard deviations (RSDs) in the range 5–15%. Sample volumes up to 1 L provided enrichment factors up to 1000, achieving accurate quantification of concentrations as low as 5 ng L −1 . The analytes were simultaneously and quantitatively eluted from the RGO–silica cartridge in a single fraction by using acetonitrile combined with aqueous tetrabutyl ammonium hydroxide. The batch-to-batch reproducibility was verified on three independently prepared RGO–silica samples. RGO–silica was advantageous in terms of adsorption capacity and reusability with respect to commercial sorbents; the cartridge proved to be reusable for at least 10 consecutive extractions, with no significant loss of efficiency (recovery >70%). The analytical procedure was applied to the determination of FQs in actual environmental waters.

This work presents a systematic study of cellulose (CLS) as a sacrificial biomass for photocatalytic H2 evolution from water. The idea is indeed to couple a largely available and not expensive biomass, and water, with a renewable energy like solar radiation. An aqueous CLS suspension irradiated either at 366 nm (UV-A) or under sunlight in the presence of Pt/TiO2 behaves as a H2 evolving system. The effects of irradiation time, catalyst and CLS concentrations, pH and water salinity are studied. Addition of CLS to the sample significantly improved H2 evolution from water splitting, with yields up to ten fold higher than those observed in neat water. The mechanism of the photocatalytic process relies on the TiO2-mediated CLS hydrolysis, under irradiation. The polysaccharide depolymerisation generates water-soluble species and intermediates, among them 5-hydroxymethylfurfural (HMF) was identified. These intermediates are readily oxidized following the glucose photoreforming, thus enhancing water hydrogen ion reduction to give gas-phase H2. The formation of “colored” by-products from HMF self-polymerization involves a sort of “in situ dye sensitization” that allows an effective photoreaction even under solar light. The procedure is evaluated and successfully extended on cellulosic biomasses, i.e. rice husk and alfalfa (Medicago sativa) stems, not previously investigated for this application.

In this work we present a multichannel chemical sensor based on Surface Plasmon Resonance (SPR) in a Plastic Optical Fiber (POF), for the detection of metal ions. The SPR sensing platform was realized removing the cladding of a plastic optical fiber along half circumference, spin coating on the exposed core a buffer of Microposit S1813 photoresist, and finally sputtering a thin gold film by using a sputtering machine. The planar gold layer can be employed for the preparation of a Self Assembled Monolayer (SAM) with specific binding receptor. In the present study two different ligands for Fe(III) and Cu(II) are linked on the gold surface obtaining two SAM-POF sensors. © 2014 AEIT.

The preparation, characterization and analytical application of a chemically modified gold electrode (CME), based on ω-thio nitrilotriacetic acid derivative (N-[5-[[[[20-(acetylthio)-3,6,9-trioxaeicos-1-yl]oxo]carbonyl]amino]-1carboxypentyl]iminodiacetic acid) self-assembled monolayer (SAM), have been described. The electrode has been characterized by electrochemical techniques and tested for its response towards metallic ions, demonstrating to be effective for the determination of ionized iron at sub-μg L(-1) level by differential pulse cathodic stripping voltammetry (DPCSV). The analytical response towards iron in natural water (tap water, marine water) and the interference of ions usually present and chelating agents (humic acids and EDTA as model ligand of high complexing capacity) have been evaluated.

The concentration of more than 25 trace elements have been determined in total air particulate matter and in the size segregated fractions from the urban area of Pavia (North Italy). The PM10 fraction was also collected and analyzed. A study of the solubility in water and in physiological solution of the trace elements contained in the PM10 was also carried out. The resulting solutions were further submitted to column chromatography using Chelex 100 to perform a preliminary chemical characterization. INAA was used as the main analytical technique. ET-AAS was used for all Pb and Cd measurements and, in some cases, for the analysis of V, Mn, Cu and Ni.

The feasibility of ligand titrations with metal ions using complexing resins as sorbing solids is evaluated. The resins considered were the iminodiacetic resin Chelex 100, the carboxilic resin Amberlite CG50, and the anion exchange resin AG1X8, whose sorbing properties for aluminium(III) and copper(II) were known from previous investigations. Synthetical solutions containing known concentrations of ligands, EDTA and IDA were titrated separately with aluminium(III) and copper(II), by adding known concentration of titrant metal, and measuring the concentration of metal ion sorbed on the resin, c. The concentration of free metal ion was evaluated from c by the relationship: [M] = cV/K*w. K* is the ratio of the concentration of metal ion sorbed on the resin to the free metal ion in solution, and strongly depends on the conditions. In the case of the resins used in this investigation it can be calculated since the sorption equilibria of the metal ions are known. The total concentration of the ligands and the conditional stability constants are evaluated by a linearization procedure, previously proposed and widely used for ligand titrations, based on the hypothesis that only a 1 to 1 metal to ligand complex is formed. Accurate results are always obtained if the titration is properly carried out, i.e. using the appropriate resin, and adding the required excess of titrant. Some criteria are suggested to evaluate the results obtained, which can be useful when solutions of unknown composition are titrated. For these evaluations the sorption equilibria of metal ions on the resin at the considered conditions must be exactly known. In this paper they were evaluated from the sorbing properties of the resins, previously investigated according to the Gibbs–Donnan model. This is very convenient, since it avoids the experimental determination at each particular set of conditions, which is often even impossible, yet giving acceptable results.

Cytotoxicity of cadmium-containing silica nanoparticles Cd-SiO2NPs (0.05–100 µg/mL) versus SiO2NPs and CdCl2was evaluated by anin vitrotest battery in A549 by assessing (i) mitochondrial function, (ii) membrane integrity/cell morphology, (iii) cell growth/proliferation, (iv) apoptotic pathway, (v) oxidative stress, after short- (24–48 h) and long-term (10 days) exposure. Both Cd-SiO2NPs and CdCl2produced dose-dependent cytotoxic effects: (i)MTT-assay: similar cytotoxicity pattern was observed at both 24 and 48 h, with a more Cd-SiO2NPs pronounced effect than CdCl2. Cd-SiO2NPs induced mortality (about 50%) at 1 μg/mL, CdCl2at 25 μg/mL; (ii)calcein-AM/PI staining: decrease in cell viability, noticeable at 25 μg/mL, enhanced markedly at 50 and 100 μg/mL, after 24 h. Cd-SiO2NPs induced higher mortality than CdCl2(25% versus 4%, resp., at 25 μg/mL) with further exacerbation after 48h; (iii)clonogenic assay: exposure for longer period (10 days) compromised the A549 proliferative capacity at very low dose (0.05 μg/mL); (iv) a progressive activation ofcaspase-3 immunolabellingwas detected already at 1 μg/mL; (v) GSH intracellular level was modified by all compounds. In summary,in vitrodata demonstrated that both Cd-SiO2NPs and CdCl2affected all investigated endpoints, more markedly after Cd-SiO2NPs, while SiO2NPs influenced GSH only.

Ion selective electrodes (ISE) for organic ions are in principle suitable for rapid in situ determinations. A critical point in the development of ISEs is to find out specific receptors. In this investigation the possibility of developing solid state ISEs with molecularly imprinted acrylic polymers (MIP) as a recognition element was investigated. As a proof case, an all-solid-state ISE for dopamine (DAH+) was prepared. In order to attain a real miniaturization of the whole measuring device, the reference electrode too was an all-solid-state one, based on the same polymer used for the working electrode but in the absence of template. A screen printed graphite electrode modified with multiwalled carbon nanotubes as an ion to electron transducing layer was used as conducting substrate. The cell potential linearly increases at dopamine concentration higher than 10−4 M, but the sensibility is less than nernstian (16 mV/dec). The sensor is very selective for the template.