Recent Developments in Multichannel Raman Microprobing

This paper reviews the capabilities of multichannel Raman microprobing instruments with emphasis on some major innovative progress recently proposed which looks promising for the development of new fields of application. This new progress includes: confocal Raman microanalysis that provides better spatial resolution and background rejection, confocal Raman mapping that revitalizes the field of Raman imaging pioneered by us 20 years ago, the coupling of molecular Raman microanalysis to elemental electron microprobe, and finally, Raman spectroscopy with near-infrared excitation which permits avoiding the fluorescence limitation of visible Raman spectroscopy

Near-infrared Fourier transform room-temperature photoluminescence of erbium complexes

A modified Fourier transform (FT) Raman bench spectrometer designed for the detection of weak light emission in the 800–1700 nm wavelength region has been used to demonstrate the advantages of FT spectroscopy for measuring near-infrared photoluminescence spectra of lanthanide complexes with a good resolution and very good sensitivity. This apparatus has been tested with an ultraviolet laser source (325 nm) on three standard erbium complexes. The 4I13/24I15/2 emission of tris-(acetylacetonato) (1,10 phenanthroline) erbium [Er(acac)3(phen)], tris-(4,4,4,-trifluoro-1-(2 thenoyl)-1,3-butenedione) (1,10 phenanthroline) erbium [Er(TTFA)3(phen)] and tris(8-hydroxyquinolinato) erbium [Erq3] has thus been recorded in solution and in the solid state and compared with literature. ©2003 American Institute of Physics

LE MICRODIL 28 : MICROSONDE RAMAN À DÉTECTION MULTICANALE

Nous décrivons une nouvelle génération de microsonde Raman : le Microdil 28 qui bénéficie des avantages de la détection multicanale à barrette de photodiodes intensifiée et nous présentons les avantages qui résultent de la détection simultanée des informations spectrales.We describe a new laser Raman microprobe : the Microdil 28 that benefits from the advantages of the multichannel intensified photodiodes array detector and we point out some merits resulting from its fast detection capabilities

LASER RAMAN MICROPROBING TECHNIQUES

L'intérêt de la microspectrométrie Raman pour l'analyse moléculaire non destructive ainsi que l'évolution des techniques sont présentés. Quelques exemples d'application illustrent l'exposé.The analytical ptential of microRaman spectroscopy for non destructive molecular analysis is presented. The evolution of the techniques and some applications are presented

Resolving the internal structure of individual atmospheric aerosol particle by the combination of Atomic Force Microscopy, ESEM-EDX, Raman and ToF-SIMS imaging

In this study, internal structures of individual aerosol particles were resolved by using micro-analytical techniques in combination. We demonstrated the practical applicability of the combined use of Atomic Force Microscopy (AFM), Environmental Scanning Electron Microscopy coupled with Energy-Dispersive X-ray analysis (ESEM-EDX), Raman Microspectrometry (RMS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to provide morphological, elemental, molecular and outer surface imaging of the same individual airborne particles for the first time. The characterization of single particles collected in the industrial atmosphere influenced by marine air masses demonstrated the physicochemical evolution of the particles in a short time period. The marine-derived particles were mainly encountered as genuine sea salts internally mixed with reacted sea salts such as NaNO3 and liquid NO3- which are covered by an organic thin layer. The particles collected downwind the industrial area were solid particles composed of an internal mixture of iron oxides and of marine-derived particles coated with an organic layer. The formation of these particles is a result of coalescence, agglomeration and drying processes occurring in the atmosphere during the transport of particles in a short time period (~15min). It is demonstrated that the combined use of the different types of spectral and imaging data from the same individual particles in atmospheric aerosol sample provides richer information on their physicochemical characteristics than when those techniques were used alone or when two techniques in combination

Silicon nanowires coated with silver nanostructures as ultrasensitive interfaces for surface-enhanced Raman spectroscopy

Silver nanoparticles (Ag NPs) were chemically deposited on silicon nanowires (SiNWs), prepared using the vapor−liquid−solid (VLS) growth mechanism, using an in situ electroless metal deposition technique. The resulting SiNWs/Ag NPs composite interfaces showed large Raman scattering enhancement for rhodamine 6G (R6G) with a detection limit of 10−14 M and an enhancement factor of 2.3 × 108. This large enhancement factor was attributed to the presence of “hot” spots on the SiNWs/Ag NPs substrate

Optimisation of the chemical generation of singlet oxygen (¹Ο₂, ¹Δ_g) from the hydrogen peroxide–lanthanum(III) catalytic system using an improved NIR spectrometer

A near-IR chemiluminescence spectrometer designed to study chemical sources of singlet oxygen (1Ο2, 1Δg), was built by coupling a reactor compartment to a nitrogen-cooled Ge diode through a bundle of optical fibres. This device was used to optimise the generation of 1O2 from the hydrogen peroxide–lanthanum(III) catalytic system. The reaction kinetics were studied with a 2333//12 screening experimental design comprising twelve experiments. The influence of six factors was examined: the nature of the lanthanum salt (hydroxide, oxide or nitrate) and its concentration (0.05 or 0.1 mol L-1), the pH value (5, 7 or 9), the concentration of H2O2 (0.5, 1 or 2 mol L-1), the temperature (20 or 30 °C) and the concentration of EDTA (0 or 5 mmol L-1). Two responses were measured: the rate of H2O2 disproportionation and the intensity of the luminescence of 1O2 at 1270 nm. The essential factor is the nature of the lanthanum salt since La(NO3)3 induces the disproportionation of H2O2 about 60 × faster than La2O3 or La(OH)3. Other influencing factors are the pH value, the concentration of H2O2, the temperature and the concentration of the lanthanum salt whereas the concentration of EDTA has no effect on the reaction. The catalytic activity of La(NO3)3 was then investigated in further detail by studying the influence of two factors (pH and [H2O2]) thanks to a Doehlert design