Sol-gel technology provides a simple and reliable method for solid-phase microextraction (SPME) fiber preparation through in situ creation of surface-bonded organic-inorganic hybrid coatings characterized by enhanced thermal stability and solvent-resistance properties that are important for the coupling of SPME with GC and HPLC, respectively. The sol-gel coating technology has led to the development of an extensive array of sol-gel sorbent coatings for SPME. In this article, sol-gel microextraction coatings are reviewed, with particular attention on their synthesis, characterization, and applications in conjunction with GC and HPLC analyses. In addition, the development of sol-gel-coated stir bars, their inherent advantages, and applications are discussed. Next, the development and applications of sol-gel capillary microextraction (CME) in hyphenation with GC and HPLC is extensively reviewed. The newly emerging germania- and titania-based sol-gel microextraction phases look promising, especially in terms of pH and hot solvent stability. Finally, sol-gel monolithic beds for CME are reviewed. Such monolithic beds are in a position to greatly improve the extracting capabilities and enhanced sensitivity in CME.
Two palladium complexes, [Pd(L1)(OAc))] (1) and [Pd(L2)(OAc))] (2), have been synthesized by reacting Pd(OAc)2 and the new thioetherazo (HL) ligands (HL = 2(RS)C6H4NH-N=C(COCH3)-SC6H5, R= C6H5 (HL1), CH3 (HL2)). The ligands...
This work describes the preparation of an analytical microextraction sorbent using a simple and versatile sol–gel hybrid composite, i.e., aramid oligomers wrapping multi-walled carbon nanotubes (CNTs) covalently bonded to a porous silica network.
Detecting tissue pH in vivo is extremely vital for medical diagnosis and formulation of treatment decisions. To this end, many investigations have been carried out to develop an accurate and efficient method of in vivo pH measurement. Most of the techniques developed so far suffer from inadequate accuracy, due to poor sensitivity at low concentration of the target or nonspecific interactions within the tissue matrix. To overcome these issues, we describe herein the development of a simple, yet reliable, way to estimate pH with high precision using a Gd(III)-DOTA-silyl-based acid-labile group as a pH-sensitive contrast agent with Magnetic Resonance Imaging (MRI). With this method, a change in T 1 weighted image intensity of the newly developed pH-sensitive contrast is directly linked to the proton concentration in the media. As a result, we were able estimate the pH of the target with 95% reliability.
Nanogenerator-based piezoelectric
materials have been the focus
of extensive studies to foster the next generation
of autonomous microdevices capable of harvesting energy from their
environment with a high rate of efficiency. We developed a piezoelectric
nanogenerator capable of converting light energy into electrical current
by using a combination of an enhanced piezoelectric nanocomposite
(P(VDF-TrFE)-BaTiO3) and a photosensitive molecular motor
(pseudo-stilbene derivative) that act as an alternative to external
mechanical stress. This approach was based on the ability of these
molecular motors to harvest light and convert it into constant mechanical
stress via light-induced geometrical changes that provoke a mechanical
deformation of the host piezo-nanocomposite, resulting in the appearance
of an electrical current.
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