Multianalytical approach to the analysis of English polychromed alabaster sculptures: μRaman, μEDXRF,and FTIR spectroscopies

A complete study of several English polychromed alabaster sculptures is presented. The support, pigment, and binders were characterised by combining μEDXRF, μRaman, and FTIR spectroscopies. Among the pigments, minium, vermilion, lead white, carbon black, red iron oxide, and a degraded green copper pigment were determined, together with gold leaf. The presence of the rare mineral moolooite (copper oxalate) was also found as a degradation product in the green areas, where weddellite (calcium oxalate dihydrate) was also determined. These facts, together with degradation of the green copper pigment, suggest microbiological degradation of the original materials. Remains of glue and a varnish were also determined by FTIR spectroscopy and principal-components analysis (PCA) of the spectra. Finally, PCA analysis was carried out to confirm whether the pieces came from the same quarry.     

A new and efficient method for conjugate addition of trialkylphosphites to 3-acylsubstituted coumarins

A new and efficient conjugate addition of trialkylphosphites to 3-ω-bromoacetylcoumarin 1 catalysed by p-toluenesulfonic acid (TsOH) has been studied. Under the same conditions, an enolphosphate gave the corresponding esters of 3-acetyl-4-phosphono-2-oxochromans in high yields. The use of TsOH in the reaction of 3-acetyl-, 3-benzoyl-, and 3-ethoxycarbonyl coumarins led mainly to 1,4-addition products—the corresponding 3-acyl-4-dialkylphosphono-2-oxochromans—in very good yields.     

Preparation of mesoporous/macroporous materials in highly concentrated emulsions based on cubic phases by a single-step method

A novel and simple single-step method for the preparation of meso/macroporous silica materials is described, which consists in templating in highly concentrated emulsions with a cubic liquid crystal in the continuous phase. Tetraethyl orthosilicate (TEOS) was solubilized in the aqueous continuous phase of highly concentrated emulsions stabilized by C(12)(EO)(8) and a PEO-PPO-PEO block copolymer nonionic surfactant, with a cubic liquid crystalline phase of the Fd3m type. The resulting silica materials were characterized by small-angle X-ray scattering, nitrogen sorption and transmission electron microscopy. The results showed that a dual pore size distribution was obtained, consisting of mesopores in the nanometer range and macropores between 1 and 5 μm. These dual meso/macroporous silicas with bimodal pore size distribution can possess specific surface areas higher than 400 m(2)/g.     

Development of a focused ultrasonic-assisted extraction of polycyclic aromatic hydrocarbons in marine sediment and mussel samples

Focused ultrasonic-assisted extraction (FUSE) is a new and particular technique based on the cavitation effect. In this work, the focused ultrasound assisted extraction was studied and developed for the extraction of polycyclic aromatic hydrocarbons from marine sediments and mussel tissues. The variables influencing the extraction (amplitude of the ultrasound pulse, the extraction time and the solvent) were studied by a full factorial design and a central composite design. As a result, flat response surfaces were obtained and the most convenient conditions were 45% of ultrasound amplitude, 120 s of extraction time and 5 mL of acetone. Both accuracy and precision of the method were evaluated by means of two certified reference materials (marine sediment and mussel tissue) and the results were also compared to those obtained by microwave assisted extraction.     

Ultrasonic‐assisted derivatization of estrogenic compounds in a cup horn booster and determination by GC‐MS

Cup horn boosters are miniaturized ultrasound baths that maximize efficiency and precision. The optimization of an ultrasonic‐assisted derivatization step by means of a cup horn booster and the determination of estrone, 17β‐estradiol, estriol, 17α‐ethynyl estradiol and mestranol was developed by GC‐MS. Different derivatization reagents and solvents were studied for maximizing the di‐derivatization of 17α‐ethynyl estradiol under ultrasound energy. Only N,O‐bis(trimethylsilyl)trifluoroacetamide with 1% of trimethylchlorosilane in pyridine gave satisfactory results and this mixture was further used in the optimization of the ultrasound assisted derivatization. The experiment designs included sonication time (1–10 min), sonication power (20–80%), sonication cycles (1–9), derivatization reagent volume (25–125 μL) and solvent volume (25–125 μL). Once the optimum conditions were fixed, the effect of organic matter and the frequency of the water bath change were studied. Finally, the validation of the analytical method was carried out using spiked natural and synthetic waters. Recoveries (natural (138–70%) and synthetic (112–89%)), the LODs (0.35–1.66 ng/L), and LOQs (1.16–5.52 ng/L) and the precision (0.2–5.3%) of the method were studied. This is the first work in the literature where a cup horn booster is used with the aim of minimizing derivatization time during the determination of estrogenic compounds.     

Microarray and nanotechnology applications of functional nanoparticles

Microarrays are a sensitive, specific, miniaturized devices that may be used to detect selected DNA sequences and proteins, or mutated genes associated with human diseases. Several methods have been developed to detect the binding of complementary molecules to microarrays by generating an optical signal. One of the most commonly used molecular labeling methods at present is fluorescence, but its application is expensive due to sophisticated equipment required to design the platform, hybridize it, and interpret the images derived from microarray-based studies. This is a drawback for its use in laboratories and clinical services. Another less expensive procedure having similar sensitivity and specificity is DNA and protein functional nanoparticles (FNP). Nanoparticles are sphere-like biocompatible materials made of inert silica, metal or crystals of a nanometer in size, which are generally coated with a thin gold layer. They may be used as hybridization probes in single nucleotide polymorphism (SNP) screening and to detect biological markers for cancer, infection, and cardiovascular diseases.