High-Resolution Mass Spectrometry applied to the identification of new metabolites and transformation products of quinolones in chicken muscle tissues

The aim of this work was the identification of new metabolites and transformation products (TPs) in chicken muscle from Enrofloxacin (ENR), Ciprofloxacin (CIP), Difloxacin (DIF) and Sarafloxacin (SAR), which are antibiotics that belong to the fluoroquinolones family. The stability of ENR, CIP, DIF and SAR standard solutions versus pH degradation process (from pH 1.5 to 8.0, simulating the pH since the drug is administered until its excretion) and freeze-thawing (F/T) cycles was tested. In addition, chicken muscle samples from medicated animals with ENR were analyzed in order to identify new metabolites and TPs. The identification of the different metabolites and TPs was accomplished by comparison of mass spectral data from samples and blanks, using liquid chromatography coupled to quadrupole time-of-flight (LC-QqToF) and Multiple Mass Defect Filter (MMDF) technique as a pre-filter to remove most of the background noise and endogenous components. Confirmation and structure elucidation was performed by liquid chromatography coupled to linear ion trap quadrupole Orbitrap (LC-LTQ-Orbitrap), due to its mass accuracy and MS/MS capacity for elemental composition determination. As a result, 21 TPs from ENR, 6 TPs from CIP, 14 TPs from DIF and 12 TPs from SAR were identified due to the pH shock and F/T cycles. On the other hand, 14 metabolites were identified from the medicated chicken muscle samples. Formation of CIP and SAR, from ENR and DIF, respectively, and the formation of desethylene-quinolone were the most remarkable identified compounds.

Solid-Phase Synthesis of New Trp(Nps)-Containing Dipeptide Derivatives as TRPV1 Channel Blockers

Trp(Nps)-Lys-NH2 derivatives, bearing alkyl or guanidine groups either at the N-terminus or on the Lys side-chain or at both positions were conveniently prepared on solid-phase and evaluated as TRPV1 channel antagonists.

Identification of new transformation products during enzymatic treatment of tetracycline and erythromycin antibiotics at laboratory scale by an on-line turbulent flow liquid-chromatography coupled to a high resolution mass spectrometer LTQ-Orbitrap

This work describes the formation of transformation products (TPs) by the enzymatic degradation at laboratory scale of two highly consumed antibiotics: tetracycline (Tc) and erythromycin (ERY). The analysis of the samples was carried out by a fast and simple method based on the novel configuration of the on-line turbulent flow system coupled to a hybrid linear ion trap – high resolution mass spectrometer. The method was optimized and validated for the complete analysis of ERY, Tc and their transformation products within 10 min without any other sample manipulation. Furthermore, the applicability of the on-line procedure was evaluated for 25 additional antibiotics, covering a wide range of chemical classes in different environmental waters with satisfactory quality parameters. Degradation rates obtained for Tc by laccase enzyme and ERY by EreB esterase enzyme without the presence of mediators were ∼78% and ∼50%, respectively. Concerning the identification of TPs, three suspected compounds for Tc and five of ERY have been proposed. In the case of Tc, the tentative molecular formulas with errors mass within 2 ppm have been based on the hypothesis of dehydroxylation, (bi)demethylation and oxidation of the rings A and C as major reactions. In contrast, the major TP detected for ERY has been identified as the “dehydration ERY-A”, with the same molecular formula of its parent compound. In addition, the evaluation of the antibiotic activity of the samples along the enzymatic treatments showed a decrease around 100% in both cases

La Incidencia de las nuevas tecnologías en los hábitos formativos de los estudiantes de magisterio = The Impact of new technologies in the learning habits of teacher students

Este trabajo persigue dos objetivos: el primero es analizar el uso de las TIC en un grupo de estudiantes de segundo curso de Magisterio de la Universidad de Girona; el segundo es analizar los documentos normativos legales que establecen el currículum de educación primaria en Cataluña para observar qué tipo de papel juegan las TIC en las nuevas programaciones educativas. La primera parte se ha llevado a cabo mediante una encuesta, cuyos resultados permiten observar tres aspectos distintos: el primero, que una parte considerable del grupo considera las TIC más como un complemento para el aprendizaje que como una forma de aprendizaje; el segundo, que a pesar de hacer un uso considerable de las TIC, el conocimiento que tienen de ellas es muy básico y utilizan aplicaciones muy genéricas; y el tercero es que una parte de sus propuestas didácticas para el uso de las TIC son propuestas tradicionales simplemente adaptadas a un nuevo instrumento, sin buscar realmente la innovación que puede suponer la incorporación de las TIC. En la segunda parte del artículo, a partir del análisis e interpretación de los documentos legales que establecen el currículum de Educación Primaria, se observa que en un mismo documento conviven aserciones sobre las TIC como complemento al aprendizaje de contenidos con otras formulaciones que consideran las TIC como constructoras de conocimiento. A partir del perfil de los estudiantes y del estado de los documentos legales, al final del artículo se hacen propuestas para formar al futuro maestro teniendo en cuenta las TIC como herramientas básicas de conocimiento

Analysis, improvement, and development of new firmware for the smart citizen kit ambient board

The objective of this project was to develop firmware for both the Arduino-compatible boards of the Smart Citizen initiative, and for the RTX4100 low-power WiFi.