1,721,244 research outputs found
Special Issue: Nano-Catalysts and Nano-Technologies for Green Organic Synthesis
Full text linkCatalysis by transition-metal nanoparticles has undergone an explosive growth during the past decade. This special issue presents the general trends in the current research in this field, the present situation concerning scope and limitations, as well as the future perspectives. Original contributions are also presented on the applications of nano-catalysts to the green synthesis
Chapter 7: Silver nanoparticles as nanoantimicrobials: Bioactivity, Benefits and Bottlenecks
No full textAn electrospray ionization-ion trap mass spectrometry (ESI-MS/MSn) study of dehydroascorbic acid hydrolysis at neutral pH
No full textNon-destructive depth profile reconstruction of bio-engineered surfaces by parallel angle resolved x-ray photoelectron spectroscopy
No full textLabel-free biosensors are of considerable interest for various clinical and biological applications. In these systems, achieving an optimized receptor immobilization strategy critically influence the sensing performance in terms of specificity, sensitivity, response kinetics and detection limits. However, monitoring the receptor spatial organization and the interfaces composition on a nanometer or sub-nanometer scale is a very hard challenge.
In the present contribution Parallel Angle Resolved X-ray Photoelectron Spectroscopy (PAR-XPS) was proposed as useful tool to address the challenge of probing the near-surface region of bio-active sensors surface (1). A model receptor was chosen and a well-established functionalization procedure (2) was systematically characterized by PAR-XPS. Commercially available Thermo Avantage-ARProcess software was used to generate non-destructive concentration depth profiles of protein functionalized silicon oxide substrates. At each step of the functionalization procedure, the surface composition, the over layer thickness, the in-depth organization and the in-plane homogeneity were evaluated. Compared to multi-techniques characterization approaches previously proposed in the literature, the present analytical approach boasted the peculiar advantage of providing, simultaneously, morphological and compositional information from the same data set. The critical discussion of the generated profiles highlighted the relevance of the information provided by PAR-XPS technique
Simultaneous determination of ochratoxin A and cyclopiazonic, mycophenolic and tenuazonic acids in cornflakes by solid-phase microextraction coupled to high performance liquid chromatography
No full textA solid-phase microextraction (SPME) method, coupled to liquid chromatography with diode array UV detection (LC-UV/DAD), for the simultaneous determination of cyclopiazonic acid, mycophenolic acid, tenuazonic acid, and ochratoxin A is described. Chromatographic separation was achieved on a propylamino-bonded silica gel stationary phase using acetonitrile/methanol/ammonium acetate buffer mixture (78:2:20, v/v/v) as mobile phase. SPME adsorption and desorption conditions were optimized using a silica fiber coated with a 60 ím thick polydimethylsiloxane/divinylbenzene film. Estimated limits of detection and limits of quantitation ranged from 3 to 12 ng/mL and from 7 to 29 ng/mL, respectively. The method has been applied to cornflake samples. Samples were subjected to a preliminary short sonication in MeOH/2% KHCO3 (70:30, v/v); the mixture was evaporated to near dryness and reconstituted in 1.5 mL of 5 mM phosphate buffer (pH 3) for SPME followed by LCUV/ DAD. The overall procedure had recoveries (evaluated on samples spiked at 200 ng/g level) ranging from 74 ( 4 to 103 ( 9%. Samples naturally contaminated with cyclopiazonic and tenuazonic acids were found; estimated concentrations were 72 ( 9 and 25 ( 6 ng/g, respectively
Approaches to Synthesis and Characterization of Spherical & Anisotropic Copper Nanomaterials
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