Search results for " infrared spectroscopy"
showing 10 items of 438 documents
Recent developments in flow-analysis vibrational spectroscopy
2007
Abstract This review deals with developments in the new century on the use of vibrational spectroscopy techniques for detection in flow-injection analysis (FIA) systems. To provide a picture of the evolution, highlights and future developments in this field, we revisited Fourier transform infrared (FTIR), in the mid-IR and near-IR ranges, and FT-Raman spectrometry applications using different approaches, from classical FIA to modern (sequential injection analysis (SIA) or multicommutation). We used the analytical abstracts database for 2000–06 for the literature search, but we based this review very much on the experience of our team in this field.
Evidences on alterations in skeleton composition and mineralization in a site-attached fish under naturally acidified conditions in a shallow CO2 vent
2021
Abstract Background Ocean acidification may affect fish mineralized structures (i.e. otoliths and skeleton). Methods Here, we compared the elemental composition of muscle and skeleton and the mineral features of skeleton in the site-attached fish Gobius bucchichi naturally exposed to high pCO2/low pH conditions in a shallow CO2 vent with fish of the same species exposed to normal pH. Results Overall, no skeleton malformations were found in both pH conditions, but among-site differences were found in the elemental composition. Interestingly, higher Ca/P values, inducing a moderate skeleton maturation, were found in fish exposed to acidified conditions than in controls. Conclusion Our finding…
Ciprofloxacin Polymers Derived from Diallyltin and Divinyltin Dihalides
2008
The initial synthesis of condensation polymers from newly available divinyltin dichloride and diallyltin dichloride and ciprofloxacin is accomplished employing a modified interfacial polycondensation process. The polymeric (DP are about 2,000) products are rapidly (less than 15 seconds) formed in good yield. Infrared spectroscopy shows the formation of Sn-O and Sn-N bonds as predicted from the proposed structure. F-MALDI MS also shows ion fragments containing organotin in the predicted isotopic abundances as well as ion fragments containing both organotin and ciprofloxacin. The polymers exhibit low toxicity towards healthy WI-38 cells with variable toxicities towards a variety of cancer cel…
Boron doping of silicon rich carbides: Electrical properties
2013
Boron doped multilayers based on silicon carbide/silicon rich carbide, aimed at the formation of silicon nanodots for photovoltaic applications, are studied. X-ray diffraction confirms the formation of crystallized Si and 3C-SiC nanodomains. Fourier Transform Infrared spectroscopy indicates the occurrence of remarkable interdiffusion between adjacent layers. However, the investigated material retains memory of the initial dopant distribution. Electrical measurements suggest the presence of an unintentional dopant impurity in the intrinsic SiC matrix. The overall volume concentration of nanodots is determined by optical simulation and is shown not to contribute to lateral conduction. Remarka…
Bioprospective of Sorbus aucuparia leaf extract in development of silver and gold nanocolloids
2010
At the present time the bioprospective field is a dynamic area of research. The rapid biosynthesis of silver and gold nanoparticles without using toxic chemicals is reported here. Sorbus aucuparia is omnipresent in Europe. The aqueous leaves extract of the plant were used as reducing agent for the synthesis of silver and gold nanoparticles from their salt solutions. The synthesized nanoparticles were spherical, triangular and hexagonal in shape with an average size of 16 and 18nm for silver and gold, respectively. Different extract quantities, metal concentrations, temperatures and contact times were investigated to find their effect on nanoparticles synthesis. The resulting silver and gold…
Monitoring of the smoking process by multicommutation Fourier Transform Infrared spectroscopy
2007
Abstract Nicotine was selected as the target molecule for monitoring of the smoking process by multicommutation Fourier Transform Infrared spectroscopy (FTIR). The method involved the use of CHCl3 for on-line extraction of nicotine from tobacco, cigarette filters and tobacco ash from NH4OH alkalinized samples, and absorbance measurement of the characteristic band at 1316 cm−1 in the stopped-flow mode, by obtaining the peak area in the range between 1334 and 1300 cm−1. Under the best operational conditions, the procedure developed provided a detection limit of 0.05 mg mL−1 nicotine, corresponding to 0.5 mg g−1 in the solid sample, a relative standard deviation less than 2.5%, and a sampling …
FT-IR Investigation of the Urea State in AOT Reversed Micelles
2001
Abstract FT-IR spectra of the urea/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/CCl 4 system as a function of the urea-to-AOT molar ratio ( R urea ) at a fixed AOT concentration ([AOT]=0.1 mol·kg −1 ) have been recorded at 25°C. The experimental data are consistent with the hypothesis that at low R urea values urea is dispersed as monomers among the hydrophilic core of AOT reversed micelles, whereas at R urea >0.13 it is encapsulated as small molecular clusters. These clusters display some departures from the H-bonded structure of the pure solid urea attributable to their small size and to urea–AOT head group interactions. The stretching modes of AOT sulfonate groups are affected by the pr…
Thermoanalytical studies on sodium 1,2-naphthoqoinone oximesolfonates
1991
Abstract Five sodium 1,2-nitrosonaphtholsulfonatea were prepared or purified and their thermal behaviour studied by TG, DTG and DSC. Pyrolysis MS technique was used to identify evolved gases and FTIR to characterize residuals. The water contents depended on preparation and conservation. The decomposition was analysed in three stages which can be formed by one or more steps. The final product was sodium sulfate in air at 530 °C and the mixture of carbon and sodium sulfide at 950 °C in nitrogen. The structure effects on decomposition is discussed.
FTIR Monitoring of Chemical Changes in Softwood During Heating
2000
Abstract A multivariate chemometric method for monitoring the mass loss of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) by IR spectroscopic determination of chemical changes occurring during the heat treatment (160 - 260 °C, 2 - 8 h) of these wood materials was developed. The method was based on the handling of FTIR data on treated and untreated wood powder samples by the partial least squares (PLS) method. In addition, unknown samples (treated and untreated pine and spruce) were classified into separate groups by the principal component analysis (PCA) method. The chemical changes occurring in the wood samples during heating were also briefly discussed.
Optimization criteria in sample selection step of local regression for quantitative analysis of large soil NIRS database
2012
International audience; Large soil spectral libraries compiling thousands of NIR (Near Infrared) reflectance spectra have been created encompassing a wide diversity and heterogeneity of spectra. Among the many chemometric approaches to the calibration of chemical and physical properties from these large libraries, local calibrations have the advantage of being able to select the most similar spectra to the spectrum of a target sample. This is particularly relevant when dealing with highly heterogeneous media such as soils, where the mineral matrix has a strong influence on spectral features. A crucial step in the implementation of local calibration procedures is the construction of local ne…