Classification of special octadecyl-bonded phases by the carotenoid test

Abstract Amongst the numerous base-deactivated ODS phases obtained by increasing the bonding density or/and by efficient endcapping treatments, some particular stationary phases have been developped, to limit the additional interactions of basic compounds with residual silanols, to work at extreme pH or with rich water mobile phases. Horizontal polymeric phases, sterically protected ones, hybrid silicas, propylene bridge, are particularly used for this purpose. Octadecyl chains with embedded polar groups and hydrophilic endcapping are also used in this goal. The properties of these phases were studied with a simple test consisting in the injection of carotenoid pigments in Subcritical Fluid Chromatography. The molecules used and the nature of the mobile phase allow the determination of hydrophobicity, polar site accessibility and type or/and bonding density of the stationary phases. Whatever the type of the phases, the particular stationary phases do not show any remarkable property, in comparison to other basedeactivated C18-bonded phases. On the other hand, embedded and polar-endcapped phases display a specific behaviour in regard of hydrophilic interactions, which are highlighted by the absence of water in the subcritical fluid. Additional properties of these phases are described, such as steric recognition and retention performances. As expected, polar-embedded phases are less retentive than classical ODS ones, but are sometimes able to provide greater steric recognition. On the other hand, the polar-endcapped phases display greater hydrophobicity than polar-embedded ones. From a simple classification diagram based on chromatographic properties, differences can be noticed between the polar-embedded groups (amide, carbamate, ether, sulfonamide) and between embedded and endcapped phases. Surprising behaviours are also noticed for some on the tested phases

Variation inter arbre des lipides de safou (Dacryodes edulis) en tant qu'indicateur de la biodiversité : mise au point méthodologique

The selection of the best individuals is a precondition to the development of extensive safou tree farming for the production of oil in sufficient yield and constant quality Thus, tree-to-tree variation of safou pulp or seed oil composition from a same ecological area was studied in order to highlight chemical biodiversity Current quantitative methods, in particular those used in triacylglycerols (TAG) analysis are time consuming and hard. High performance liquid chromatography analysis provided with an evaporative light scattering detector (HPLC/ELSD), while allowing a very good resolution of the peaks, makes possible a fast and reliable comparison of oils via radar plot representations. This paper presents this method and its validation by comparison with the quantitative ones. This study also establishes that safou tree crop, directed by the market, reduces oil chemical composition viability

How thermal treatments could impact C18 stationary phases made of core-shell particles?

National audienc

Assessment of a new MVP stationary phase for the 2D-RPLC separation of anthraquinone derivatives using descriptors stemmed from Delaunay triangulation

International audienc

Assessment of a new MVP stationary phase for the 2D-RPLC separation of anthraquinone derivatives using descriptors stemmed from Delaunay triangulation

International audienc

Mise en évidence de l’intérêt d’une nouvelle phase stationnaire (MVP) pour la séparation 2D-RPLC des dérivés d’anthraquinone par évaluation avec différents descripteurs issus de la triangulation de Delaunay

National audienc

How thermal treatments could impact C18 stationary phases made of core-shell particles?

National audienc