Development of a quantitative approach to measure phospholipids in dried drops by Raman spectroscopy

Poster (2012, October)

We present here the results obtained during our tentative to analyse quantitatively dried drops of phospholipidic solutions by Raman spectroscopy. Drops of different solutions of phospholipid were deposed ... [more ▼]

We present here the results obtained during our tentative to analyse quantitatively dried drops of phospholipidic solutions by Raman spectroscopy. Drops of different solutions of phospholipid were deposed onto different material supports. The spots were then analyses by confocal Raman microspectroscopy. Experimental settings have been optimised and the analysis of the intensity profile of the Raman signal inside the spot allows the establishment of a calibration curve for the determination of the phospholipids amount within a 1 µL solution. [less ▲]

Online monitoring of heterogeneous polymerizations in supercritical carbon dioxide by Raman spectroscopy

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2012), 13(11), 2666-2670

A novel setup is described to monitor the kinetics of homogeneous and heterogeneous reactions online using Raman spectroscopy under high pressure. The arrangement is based on a high-pressure reactor ... [more ▼]

A novel setup is described to monitor the kinetics of homogeneous and heterogeneous reactions online using Raman spectroscopy under high pressure. The arrangement is based on a high-pressure reactor equipped with a sapphire window in combination with a mobile probe that allows the collection of the back-scattered Raman signal at 360°. [less ▲]

Determination of the composition of cryolitic melts involved in the Hall-Heroult process by Raman spectroscopy

Poster (2012, August)

Charged poly(D,L-lactide) nanofibers: towards customized surface properties

in Macromolecular Symposia (2011), 309/310(1), 20-27

Surface-charged nanofibers were prepared by electrospinning technique (ESP). For this purpose, a copolymer bearing carboxylic acid functions was added to a poly(D,L-lactide) solution just before ESP ... [more ▼]

Surface-charged nanofibers were prepared by electrospinning technique (ESP). For this purpose, a copolymer bearing carboxylic acid functions was added to a poly(D,L-lactide) solution just before ESP process. In a basic medium, negative charges were therefore revealed on fiber surface. By deposition of positively charged particles or polyelectrolytes, surface properties of the fibers could be tailor-made for a specific application. This versatile method can, for example, be applied to the preparation of new biomedical scaffolds. [less ▲]

Development of an analytical method to determine the cryolitic bath composition by Raman spectroscopy

Poster (2010, April 23)

Since the end of the nineteenth century, metallic aluminium is produced by electro-deposition from a solution of aluminium oxide in cryolitic melts around 1000°C (Hall-Héroult process). The industrial ... [more ▼]

Since the end of the nineteenth century, metallic aluminium is produced by electro-deposition from a solution of aluminium oxide in cryolitic melts around 1000°C (Hall-Héroult process). The industrial melt is composed mostly of cryolite (Na3AlF6) and AlF3 and is characterized by the molar NaF/AlF3 ratio, named cryolitic ratio (CR). It turns out that the bath composition is critical: for instance, it has been shown that a small change in the Al2O3 content leads to a great change in the overvoltage required for the electrolysis. Therefore controlling the melt composition is very important in order to reduce the energy lost. Unfortunately no in situ analytical method allows studying the composition of the melt yet. Considering our experience in the study of such highly corrosive media by Raman spectroscopy and since the bath spectrum is function of both the CR and the Al2O3 content, we have proposed in the past to apply that technique to the direct determination of the melt composition. Despite the CR could be well evaluated in the lab, experimental problems however made the practical application difficult. The purpose of this presentation will be to show the new results obtained on an updated instrument: - Spectra are recorded in 20 s or less with a higher quality than before. - The previously developed home-made software was adapted to the updated instrument and various spectra analysis procedures are under study. - A procedure to prepare reference samples was also developed taking into account the homogeneity problems that have been met. - The slopes of the alumina calibration curves are depending on the bath CR, in confirmation of our previous results. - The new results are compared with the previous ones. It will be concluded that Raman spectroscopy is indeed becoming a suitable technique for developing an analytical method to determine the composition of industrial cryolitic melts. [less ▲]

An analytical method to determine the composition of cryolitic melts involved in the Hall-Heroult process by Raman spectroscopy

Poster (2010, March)

The Hall-Héroult process involves the metallic aluminium production from electroreduction of aluminium oxide in cryolitic melt (mostly composed of cryolite and aluminium fluoride) around 1000°C. In order ... [more ▼]

The Hall-Héroult process involves the metallic aluminium production from electroreduction of aluminium oxide in cryolitic melt (mostly composed of cryolite and aluminium fluoride) around 1000°C. In order to reduce the energy loss during this process, controlling the melt composition turns out to be critical. Unfortunately, no in situ analytical method allows measuring the melt composition yet. Since the Raman spectrum of the melt depends on both the cryolitic ratio (molar NaF/AlF3 ratio, CR) and the aluminium oxide content, our laboratory proposed in the past to apply Raman spectroscopy for direct melt composition determination by recording the spectrum from the top. However, experimental problems made the practical application difficult. Nowadays, the method is becoming more feasible because of new instrumental developments such as new sensitive CCD, fiber optics and new optical filters. [less ▲]