Don Quijote, novelista constructor de personajes

In Don Quixote the task of character constructon, properly the narrator's, is to a large extent usurped by the protagonist himself. He appears to rebel against the novelist and the multitude of fictitious authors and creates his own world, conferring names (Don Quixote, Dulcinea, Rocinante) and status (knight, lady, steed) on the characters, and even changing the ones they originally had. Hence, one can conceive the novel as a constant tension between author and protagonist, in which the former repeatedly punishes the latter (deceptions, beatings, final defeat) for refusing to accept the world he had initially proposed to him.In Don Quixote the task of character constructon, properly the narrator's, is to a large extent usurped by the protagonist himself. He appears to rebel against the novelist and the multitude of fictitious authors and creates his own world, conferring names (Don Quixote, Dulcinea, Rocinante) and status (knight, lady, steed) on the characters, and even changing the ones they originally had. Hence, one can conceive the novel as a constant tension between author and protagonist, in which the former repeatedly punishes the latter (deceptions, beatings, final defeat) for refusing to accept the world he had initially proposed to him

The influence of particle size on the intensity and reproducibility of Raman spectra of compacted samples

Given the growing interest in the application of Raman spectroscopy for quantitative purposes in solid pharmaceutical preparations, a revision of the effect of particle size on Raman spectra of compacted samples is presented. For this purpose, a set of tablets of potassium hydrogen phthalate (KHP) of different particle size were prepared. KHP was used because of its purity and stability, which allow to consider that samples will not be altered during measurements; but also because of its chemical structure (aromatic ring and carboxylic groups), that are present in many active pharmaceutical ingredients (API). The latter makes possible to consider KHP as a model pseudo-API. As KHP tablets only contain a pure compound, the mapping strategy that was considered for measuring our samples will not be affected by subsampling issues. The spectra variance can be attributed to the intrinsically reproducibility in recording the spectra (which mainly depends on the instrument set-up) and the site-to-site differences in elastic scattering properties. Two different instrumental optics have been studied: a macro-Raman system and a Raman microscope (500 μm and 50 μm laser spot size, respectively). The effect of the spectra preprocessing is also evaluated. The overall results demonstrate raw Raman intensity increases with particle size up to a value that depends on tablet width and that the applied spectral preprocessing (baseline correction and a unit vector normalization), reduces the differences in Raman intensities due to the particle size, but does not completely eliminate it for the lower particle sizes (< 20 μm). For tablets containing particles with predefined sizes, it corrects the mapping site-to-site differences in elastic scattering

Liquid phase microextraction integrated into a microchip device for the extraction of fluoroquinolones from urine samples

For the first time, liquid phase microextraction miniaturized into a microfluidic chip device (μLPME) combined with a HPLC procedure using diode array (DAD) has been developed for the determination of four fluoroquinolones: marbofloxacin (MRB), norfloxacin (NRF), ciprofloxacin (CPR) and danofloxacin (DNF). The microfluidic chip consisted of two symmetrical channels which contained the acceptor and sample solution separated by a flat polypropylene membrane. Also, a comprehensive study was carried out in order to determine the importance of geometry optimization in microchips based liquid phase microextraction. The optimal channel size was 23 mm length, 3 mm width and 60 μm depth. Both solutions were delivered to the chip using two syringe pumps and the extract collected was directly analyzed by HPLC. The extractions were carried out under double-flow conditions and completed after 7 min. The procedure was successfully applied to urine samples obtaining recoveries within the range of 35 and 62% for all compounds and 10 μL sample consumption. This miniaturized μLPME-chip device significantly reduced the analysis time and the sample consumption compared to the existing sample preparation techniques for fluoroquinolones.Ministerio de Educación y Ciencia TEC2006-79367-C2-1-

A simple and fast Double-Flow microfluidic device based liquid-phase microextraction (DF-µLPME) for the determination of parabens in water samples

A fast double-flow microfluidic based liquid phase microextraction (DF-µLPME) combined with a HPLC-UV procedure using diode array detection has been developed for the determination of the four most widely used parabens: Ethyl 4-hydroxybenzoate (EtP), Propyl 4-hydroxybenzoate (PrP), Butyl 4-hydroxybenzoate (BuP) and IsoButyl 4-hydroxybenzoate (iBuP) in water samples. Parabens have successfully been determined in environmental (lake and river water) samples with excellent clean up, high extraction efficiency and good enrichment factor using double-flow conditions. The microfluidic device consists of two micro-channels, which contain the acceptor and sample solution separated by a flat membrane (support liquid membrane). The sample (0.32 mM HCl) and acceptor phase (5.6 mM NaOH) are delivered to the µLPME at 10 µL min−1 and 1 µL min−1 flow rate, respectively. The extraction efficiencies are over 84% for all compounds in water samples with enrichment factors within the range of 9–11 and recoveries over 80%. The procedure provides very low detection limits between 1.6 and 3.5 µg L−1. The extraction time and the volume required for the extraction are 5 min and 50 µL, respectively; which are greatly lower compared to any previous extraction procedure for parabens analysis. In addition, this miniaturized DF- µLPME procedure significantly reduces costs compared to not only the existing methods for paraben detection, but also to the existing analytical techniques for sample preparation