Des phases stationnaires de cyclodextrine greffee pour la chromatographie liquide haute performance sont preparees par reaction de silice carboxylee avec les α- et β-cyclodextrines monosubstituees par l'ethylenediamine. Elles sont utilisees pour la separation de benzenes disubstitues isomeres, d'aminoacides, d'alcools et d'acides aromatiques et de derives du naphtalene

Chemically bonded cyclodextrin stationary phases for liquid chromatographic separation of aromatic compounds

The xylene isomers p-xylene, o-xylene, and m-xylene are aromatic hydrocarbons comprising with two methyl groups located at different positions on a benzene ring. The mixture originates from catalytic reforming of crude oil, and each individual isomer acts as a valuable intermediate; however, similar physicochemical properties make their separation difficult. This Review focuses on materials employed for their separation, such as metal–organic frameworks, molecular sieves, organics, and graphene quantum dots. Recent advances in separation of xylene isomers are summarized, including adsorption, membrane, and chromatographic separation techniques, and adsorption capacity and selectivity combined with mechanisms of separation are discussed.

Separation of Xylene Isomers: A Review of Recent Advances in Materials

Chromatographic behaviour of positional isomers on porous graphitic carbon

Gas and high-performance liquid chromatographic methods in the analysis of phenols are reviewed. Among the great number of phenolic compounds analyzed, alkylphenols, chlorophenols, dihydroxy- and trihydroxybenzenes and biphenols are chiefly considered. The advantages and drawbacks of the methods are discussed, quoting the most important work. Relationships between the structural characteristics of phenols, the stationary phase structure, the mobile phase composition and the retention data are treated. Typical examples of the conditions for GC and HPLC analysis are summarized in tables. The literature comprises over 270 references, most of them recent.

T.N. Gvozdovitch

Papers

Retention behaviour of o-, m- and p-isomers of benzene derivatives on a silica gel hydroxylated surface in liquid chromatography