Quantitative analysis of entacapone isomers using surface-enhanced Raman spectroscopy and partial least squares regression.

Surface-enhanced Raman spectroscopy (SERS) and partial least squares (PLS) regression have been applied for the quantification of entacapone isomers E and Z in solution. Nine mixtures of isomers Z and E in ethanol ranging from 0% to 100% w/w were analyzed, for a total entacapone concentration of 1 × 10(-3) mol L(-1). Upon deposition onto commercially available Klarite® gold plates, highly intense and reproducible SERS spectra were obtained from the entacapone isomers.

Surface-enhanced Raman scattering on molecular self-assembly in nanoparticle-hydrogel composite.

Surface-enhanced Raman scattering has been applied to study weak intermolecular interactions between small organic gelling molecules involved in the silver nanoparticle-hydrogel composite formation. Assembly and disassembly of the gelator molecules in close vicinity to embedded silver nanoparticles were followed by changes in Raman intensity of the amide II and carboxyl vibrational bands, whereas the strength of the bands related to benzene modes remained constant. This implied that the gelator molecules were strongly attached to the silver particles through the benzene units, while participating in gel structure organization by intermolecular hydrogen bonding between oxalyl amide and carboxyl groups.

Yb3+ as an origin of the strong anti-Stokes luminescence in NIR FT-Raman spectra of some lanthanide sesquioxides.

Strong anti-Stokes bands observed in FT-Raman spectra of Y2O3, Gd2O3 and Lu2O3 are explained by NIR luminescence of Yb3+ impurities present in sesquioxides after the excitation with the 1064 nm line of an Nd:YAG laser. Samples of Y2O3:Yb, Ga2O3:Yb, CeO2:Yb, Gd2O3:Yb and Lu2O3:Yb were prepared by solution combustion synthesis procedure using urea. All materials were investigated by FT-Raman and FT-NIR spectroscopy and characterized by X-ray powder diffraction.