Graphitized carbon reversed-phase liquid

Wan, Q.- H., Davies, M. C., Shaw, P. N., and Barrett, D. A., Retention behavior of ionizable isomers in reversed-phase liquid chromatography a comparative study of porous graphitic carbon and octadecyl bonded silica, Anal. Chem., 68, 437, 1996. 

The molecular interaction energy values of alkenes were smaller than for their related alkanes. This result supports the idea that the hydrophobic interaction due to the van der Waals energy is the predominant molecular interaction in reversed-phase liquid chromatography. No dipole-dipole or 71-71 interactions influenced the direct interaction. The lack of dipole-dipole or 71-71 interactions can be studied from chromatographic behavior on a graphitized carbon phase. 

The simplest model phase in reversed-phase liquid chromatography is a graphitized carbon phase that is a polycyclic aromatic hydrocarbon (PAH). 

Chapter 1). The widespread use of the C-18 for reversed-phase sorption is a result of the popular use of C-18 columns in high-pressure liquid chromatography (HPLC). For this reason, it gained immediate popularity for SPE applications. Other reversed phases include, C-8, C-4 (wide pore), C-2, C-1, cyclohexyl, and phenyl groups. The most commonly used reversed-phase polymeric sorbent in SPE is the styrene-divinylbenzene, or SDB. Graphitized carbon is also used. 

The mechanism of SPE is directly related to liquid chromatography toxins have to be retained by the adsorbent and not eluted by the water in the sample. Extraction sorbents are therefore similar to those used in liquid chromatography, reversed-phase ( -alkyl silica, apolar copolymers, graphitized carbon) for aqueous samples, or ion exchangers for charged compounds. Extraction parameters can be directly extrapolated from the retention times of the analytes as measured by liquid chromatography with water as the mobile phase. 

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