Quantitation of sunitinib,an oral multitarget tyrosine kinase inhibitor,and its metabolite in urine samples by nonaqueous capillary electrophoresis time of flight mass spectrometry

A rapid, sensitive, and specific method was developed and validated using a nonaqueous‐capillary electrophoresis method with TOF‐MS for determination of sunitinib and N‐desethyl sunitinib in human urine. In order to avoid ionic suppression a urine samples dilution with methanol 1:10 previous step was used. This was the only treatment step to urine samples before the injection. Despite this dilution of the urine, the detection limit was as low as 0.07 mg/L for sunitinib and 0.15 mg/L for N‐desethyl sunitinib. Separation of compounds was achieved with a mixture of 5 mM ammonium formate in methanol. The calibration curves were linear over the range of 0.5–50.0 mg/L for the two analyzed compounds. The within‐run and between‐run precisions were within 5%, while the accuracy ranged from 96.0 to 100.4%. This method can be used in routine clinical practice to monitor sunitinib and N‐desethyl sunitinib drugs in the urine of cancer patients treated with once daily administration.     

Isothermal Titration Calorimetry Study of a Bistable Supramolecular System: Reversible Complexation of Cryptand[2.2.2] with Potassium Ions

Isothermal titration calorimetry (ITC) is used to investigate the thermodynamics of the complexation of potassium ions by 1,10‐diaza‐4,7,13,16,21,24‐hexaoxabicyclo[8.8.8]hexacosane (cryptand[2.2.2]) in aqueous solution. By changing the pH of the solution it was possible to trigger the reversible complexation/decomplexation of the cryptand in consecutive in situ experiments and to assess for the first time the use of ITC to monitor the thermodynamics of a bistable system.     

Profiling of grape monoterpene glycosides (aroma precursors) by ultra‐high performance‐liquid chromatography‐high resolution mass spectrometry (UHPLC/QTOF)

A ‘suspect screening analysis’ method for grape metabolomics by ultra‐high performance‐liquid chromatography (UHPLC) and high‐resolution quadrupole‐time of flight (QTOF) mass spectrometry was recently developed. This method was applied to study grape monoterpene glycosides, the main grape aroma precursors. Since standard compounds were not available, they were tentatively identified by overlapping various analytical approaches, in agreement with the indications recommended in mass spectrometry (MS)‐based metabolomics. Accurate mass and isotopic pattern, MS/MS fragmentation, correlation between fragments observed and putative structures and between liquid chromatography coupled with mass spectrometry (LC/MS) and gas chromatography/mass spectrometry signals were studied. Seventeen monoterpene glycosides were identified without performing the hydrolytic artifacts commonly used to study these compounds which may affect sample profile. This is the first time that a detailed study of these aroma precursors has been carried out by direct LC/MS analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

Spectroscopic and structural characterization of pure and FeCl<Subscript>3</Subscript>-containing tri-<Emphasis Type="Italic">n</Emphasis>-butyl phosphate

The spectroscopic properties and liquid structure of pure tri-n-butyl phosphate (TBP) and FeCl₃/TBP solutions have been investigated by Uv–Vis and Raman spectroscopies, X-ray diffraction and conductometry. Uv–Vis and Raman spectra, supported by conductometric measurements, consistently indicate that the solubilized salt is present mostly as TBP _n [FeCl_3???n ] ⁿ⁺ and FeCl₄ ^? complex ions due to specific interaction with the TBP phosphate group. Thanks to this interaction, a high amount of salt (up to 13 % w/w) can be dissolved despite the relatively low dielectric constant of TBP. The X-ray diffractogram of pure TBP has been interpreted in terms of three main contributions which can be attributed to spatial pair correlations between atoms of interacting TBP molecules. In the presence of increasing FeCl₃ amounts, it has been observed a progressive structuring effect, exerted by the dissolved salt, on the layers of opportunely oriented TBP molecules due to the formation of the complex ionic species. By simple treatment with NaBH₄, the synthesis of Fe nanoparticles has been achieved. The absence of water, the easiness of preparation, the high amount of salt which can be suspended and the peculiar physico-chemical properties of such systems are all elements worth of note for the fields of nanoparticle synthesis and for specialized technological applications.     

Speciation of mercury by ionic liquid-based single-drop microextraction combined with high-performance liquid chromatography-photodiode array detection

Room temperature ionic liquids can be considered as environmentally benign solvents with unique physicochemical properties. Ionic liquids can be used as extractant phases in SDME, being compatible with chromatographic systems. A single-drop microextraction method was developed for separation and preconcentration of mercury species (MeHg⁺, EtHg⁺, PhHg⁺ and Hg²⁺), which relies on the formation of the corresponding dithizonates and microextraction of these neutral chelates onto a microdrop of an ionic liquid. Afterwards, the separation and determination were carried out by high-performance liquid chromatography with a photodiode array detector. Variables affecting the formation and extraction of mercury dithizonates were optimized. The optimum conditions found were: microextraction time, 20 min; stirring rate, 900 rpm; pH, 11; ionic liquid type, 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆MIM][PF₆]); drop volume, 4 μL; and no sodium chloride addition. Limits of detection were between 1.0 and 22.8 μg L⁻¹ for the four species of mercury, while the repeatability of the method, expressed as relative standard deviation, was between 3.7 and 11.6% (n = 8). The method was finally applied to the determination of mercury species in different water samples.     

Investigations by various analytical techniques to the correct classification of archaeological finds and delineation of technological features: Late Roman lamps from Egnatia: From imports to local production

Late Roman oil lamps from the archaeological site of Egnatia (Fasano, Brindisi, Italy) were characterized from physical–chemical, mineralogical and morphological points of view. Atomic Spectroscopy, Scanning Electron Microscopy and X-Ray Diffraction analyses were carried out on ceramic body and coatings with the aim of identifying the provenance of lamps, in order to arrive at a correct archaeological classification of finds and to outline their technological features.The analytical results show that the finds differ in raw materials and in production technology. The statistical multivariate treatment of compositional data of ceramic bodies groups the objects into two macro clusters and, according to a study of their different petrographic features and by a comparison with coeval pottery whose provenance is already known, suggests one group to have been imported from North Africa and the other to have been locally produced. Moreover, chemical results and in-depth archaeological analyses allow us to split the imported lamps into two subgroups, hypothesizing the first group to originate from central Tunisia and the second from the north of the same country.The analytical characterisation of finds, by different complementary techniques, has allowed us to identify the raw materials and the technological solutions used by the ancient potters from Egnatia to produce lamps. The potters made lamps which had an external appearance very similar to that of African prototypes, but which were nevertheless different as they employed the locally available materials.     

Encryption test of pseudo-aleatory messages embedded on chaotic laser signals: An information theory approach

In this Letter, we make use of two information-theory based indicators to measure the goodness of two encryption schemes commonly used within the context of chaotic communications. In particular, we have shown that the computation of the normalized Shannon entropy and the MPR-Statistical Complexity measure [M.T. Martín, A. Plastino, O.A. Rosso, Phys. Lett. A 311 (2003) 126, P.W. Lamberti, M.T. Martín, A. Plastino, O.A. Rosso, Physica A 334 (2004) 119] for different chaotic laser signals can lead to statistically significant criteria to assess the quality of several encryption techniques. The proposed measures allow, in some cases, to detect the presence of a message embedded within a chaotic carrier. They also reveal that the Chaos Modulation scheme is more reliable from the statistical point of view, when compared with the Chaos Shift Keying.     

Fisher information description of the classical-quantal transition

We investigate the classical limit of the dynamics of a semiclassical system that represents the interaction between matter and a given field. The concept of Fisher Information measure (F) on using as a quantifier of the process, we find that it adequately describes the transition, detecting the most salient details of the changeover. Used in conjunction with other possible information quantifiers, such as the Normalized Shannon Entropy (H) and the Statistical Complexity (C) by recourse to appropriate planar representations like the Fisher Entropy (F×H) and Fisher Complexity (F×C) planes, one obtains a better visualization of the transition than that provided by just one quantifier by itself. In the evaluation of these Information Theory quantifiers, we used the Bandt and Pompe methodology for the obtention of the corresponding probability distribution.