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111.
Gottardo R Chiarini A Dal Prà I Seri C Rimondo C Serpelloni G Armato U Tagliaro F 《Journal of mass spectrometry : JMS》2012,47(1):141-146
Since 2004, a number of herbal blends containing different synthetic compounds mimicking the pharmacological activity of cannabinoids and displaying a high toxicological potential have appeared in the market. Their availability is mainly based on the so-called "e-commerce", being sold as legal alternatives to cannabis and cannabis derivatives. Although highly selective, sensitive, accurate, and quantitative methods based on GC-MS and LC-MS are available, they lack simplicity, rapidity, versatility and throughput, which are required for product monitoring. In this context, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) offers a simple and rapid operation with high throughput. Thus, the aim of the present work was to develop a MALDI-TOF MS method for the rapid qualitative direct analysis of herbal blend preparations for synthetic cannabinoids to be used as front screening of confiscated clandestine preparations. The sample preparation was limited to herbal blend leaves finely grinding in a mortar and loading onto the MALDI plate followed by addition of 2 μl of the matrix/surfactant mixture [α-cyano-4-hydroxy-cinnamic acid/cetyltrimethylammonium bromide (CTAB)]. After drying, the sample plate was introduced into the ion source for analysis. MALDI-TOF conditions were as follows: mass spectra were analyzed in the range m/z 150-550 by averaging the data from 50 laser shots and using an accelerating voltage of 20?kV. The described method was successfully applied to the screening of 31 commercial herbal blends, previously analyzed by GC-MS. Among the samples analyzed, 21 contained synthetic cannabinoids (namely JWH-018, JWH-073, JWH-081, JWH-250, JWH-210, JWH-019, and AM-694). All the results were in agreement with GC-MS, which was used as the reference technique. 相似文献
112.
Luca Guideri Rossella Noschese Fabio Ponticelli 《Journal of heterocyclic chemistry》2012,49(2):297-302
1‐benzyl‐5‐(ethoxycarbonyl)‐2,3,4,5‐tetrahydropyridinium bromide undergoes ring contraction with a series of nucleophiles, getting 2,2‐disubstitued pyrrolidines. Moreover, from some of the new 2,2‐disubstitued pyrrolidines were synthesized spiro‐pyrrolidines. J. Heterocyclic Chem.,(2011). 相似文献
113.
R Mello A Alcalde-Aragonés ME González Núñez G Asensio 《The Journal of organic chemistry》2012,77(15):6409-6413
Anhydrous [2-percarboxyethyl] functionalized silica (2a) is an advantageous oxidant for performing the epoxidation of olefins 1. Epoxides 3 do not undergo the ring-opening reactions catalyzed by the acidic silica surface, except for particularly activated cases such as styrene oxide. The hydrophilic and acidic character of the silica surface does not interfere with the directing effects exerted by allylic H-bond acceptor substituents. The alkenes 1 carrying hydroxyl groups react with silica-supported peracid 2a faster than unsubstituted alkenes, thus reversing the trend known for reactions with soluble peracids. These results are attributed to the H-bond interactions of substrate 1 with the silanol and carboxylic acid groups bonded to the silica surface. 相似文献
114.
M Amado E Diez F Rossella V Bellani D López-Romero DK Maude 《J Phys Condens Matter》2012,24(30):305302
In this paper we show the electronic transport and the quantum phase transitions that characterize the quantum Hall regime in graphene placed on SiO(2) substrates at magnetic fields up to 28 T and temperatures down to 4 K. The analysis of the temperature dependence of the Hall and longitudinal resistivity reveals intriguing non-universalities of the critical exponents of the plateau-insulator transition. These exponents depend on the type of disorder that governs the electrical transport and its characterization is important for the design and fabrication of novel graphene nano-devices. 相似文献
115.
116.
Kinetics of photochromic conversion at the solid state: quantum yield of dithienylethene-based films
Pariani G Bianco A Castagna R Bertarelli C 《The journal of physical chemistry. A》2011,115(44):12184-12193
Quantum yield is one of the most important properties of photochromic systems. Unfortunately, a lack of data at the solid state exists, because measurements are intrinsically not straightforward. A kinetic model describing the conversion of the photoactive species is reported and both analytic and numeric solutions are provided according to relevant cases. The model is then applied to measure the quantum yield of dithienylethene-based polymers; the ring-opening quantum yield is measured for different laser beam profiles (i.e., Gaussian and uniform) and at different wavelengths, showing an increased value with increasing photon energy. 相似文献
117.
Rossella Arletti Simona Quartieri Ian C. Freestone 《Applied Physics A: Materials Science & Processing》2013,111(1):99-108
We applied X-ray absorption near edge spectroscopy (XANES) to obtain information on the origin of glass colour of several archaeological samples and on the oxidation conditions employed during their production. We studied a series of selected glass fragments—mainly from excavated primary and secondary production centres and dated to the first millennium AD—containing iron and manganese in a wide compositional range. In most of the studied samples iron is rather oxidised, while Mn K-edge XANES data show that, in all the studied glasses, Mn is mainly present in its reduced form (predominantly 2+), with the possible subordinate presence of Mn3+. The most oxidised samples are the HIMT (high iron manganese titanium) glasses, while the less oxidised ones belong to the primary natron glass series from the early Islamic tank furnaces at Bet Eliezer (Israel), and to the series coming from a Roman glass workshop excavated in Basinghall Street, London. In these glasses, iron is approximately equally distributed over the 2+ and 3+ oxidation states. The XANES analyses of two glasses which had been deliberately decolourized using Sb- and Mn-based decolourizers demonstrate that Sb is more effective than Mn as oxidant. 相似文献
118.
Andreea Ionescu Rossella Caligiuri Nicolas Godbert Loredana Ricciardi Massimo La Deda Mauro Ghedini Nicola Ferri Maria Giovanna Lupo Giorgio Facchetti Isabella Rimoldi Iolinda Aiello 《应用有机金属化学》2020,34(3):e5455
The in vitro biological activity towards the MDA-MB-231 triple-negative breast cancer cell line of two different series of anionic Pt(II) organometallic complexes was tested. For the first time, cytotoxic activity of anionic Pt(II) complexes has been observed. The anionic compounds of general formula NBu4[(C^N)Pt(O^O)], where (C^N) represents the cyclometalated form of 2-phenylpyridine (H(PhPy)), 2-thienylpyridine (H(Thpy)) or 2-benzo[h]quinoline (H(Bzq)), feature two different (O^O) chelated ligands: tetrabromocatechol [BrCat]2− ( 1 – 3 ) or alizarine [Aliz]2− ( 4 – 6 ). Complexes 1 – 6 displayed a significant cytotoxic effect against the studied cell line (IC50 range of 1.9–52.8 μM). For BrCat-containing complexes 1 – 3 , the biological activity was independent of the nature of the coordinated (C^N) ligand. In contrast, in the case of 4 – 6 , the cytotoxicity (significantly high for 4 ) was concomitantly induced by the presence of either the PhPy or the [Aliz]2− ligand. Since complexes 1–6 are emissive in solution, the potential use of 4 as a theranostic agent was investigated using confocal analysis. The fluorescence signal from MDA-MB-231 cells incubated with 4 indicated the localization of the compound into the cytosol region. 相似文献
119.
120.
Rossella Guadagni Nadia Miraglia Angela Simonelli Angela Silvestre Monica Lamberti Daniela Feola Antonio Acampora Nicola Sannolo 《Analytica chimica acta》2011,(1):29
Hexanal and heptanal are endogenous aldehydes coming from membrane lipid oxidation, found in lung cancer patients’ blood, and suggested as lung tumor biomarkers. Here the urinary matrix was investigated instead of blood and the difficulties related to the determination of endogenous substances in biological matrices were faced by developing an external calibration HS-SPME/GC/MS method. The methodology was validated according to international validation procedures and it was verified analyzing unknown biological samples from cancer patients and healthy subjects. Percentage accuracy and precision, ranging from −11.25 to 10.85% and from 0.45 to 4.46%, respectively, were obtained, together with limits of detection (LODs) and lower limits of quantification (LLOQs) of 0.11 and 0.23 pg μL−1 for hexanal and of 0.10 and 0.21 pg μL−1 for heptanal. Analytes percentage recoveries (66.3%, hexanal and 70.5%, heptanal) and stability were evaluated. No analytes degradation was found at room temperature, while the remarkable analytes loss found after 1 month storage suggests analyzing biological samples within a week from storage. Results coming from the analysis of unknown biological samples showed no evident differences of heptanal urinary excretion between lung cancer patients and healthy subjects (0.22–0.95 and 0.21–0.69 pg μL−1, respectively), while hexanal urinary concentrations in cancer patients (0.24–4.36 pg μL−1) were slightly higher than those found in control group ones (0.23–1.26 pg μL−1). The obtained results highly suggest to do further investigations in order to collect statistically significant biological data to discriminate between the pathological state of lung cancer patients and physiological conditions of healthy subjects, using the simple, rapid and cheap method here reported for the quantification of urinary aldehydes. 相似文献