Stationary phase graphitized carbons

Chemically bonded silica gels with cyanopropyl, aminopropyl, and diol functional groups are also available and each has been used for normal-phase as well as reversed-phase separations. Polymeric-based packings are available and can be used for ion-exchange or reversed-phase applications. Cross-linked polymeric based packings have been combined with ion-exchange materials to create a more pH-stable stationary phase. Graphitized carbon... 

Specific separation effects can be understood from the multicomponent solubility parameter theory. Specific effects for nonpolar compounds are predictable with perfluorinated and graphitized carbon black stationary phases. Specific selectivity for polar compounds in reversed-phase HPLC can be realized with polar additives to the mobile phase. 

Besides silica, silica-based and polymeric stationary phases, porous graphitized carbon (PGC), zirconium oxide and its derivatives, alumina and its derivatives have been used for the solution of special separation problems which cannot be easily solved by using traditional HPLC stationary phases. 

Bassler BJ, Hartwick RA. 1989. The application of porous graphitic carbon as an HPLC stationary phase. J Chromatogr Sci 27(4) 162-165. 

Porous graphitic carbon deposited on silica8 is a stationary phase that exhibits increased retention of nonpolar compounds relative to retention by C18. Graphite has high affinity for polar compounds and separates isomers that cannot be separated on Clg. The stationary phase is stable in 10 M acid and 10 M base. 

S. Mazan, G. Cretier, N. Gilon, J.-M. Mermet, and J.-L. Rocca, Porous Graphitic Carbon as Stationary Phase for LC-ICPMS Separation of Arsenic Compounds. Anal. Chem. 2002, 74, 1281. For another robust stationary phase, see C. J. Dunlap, C. V. McNeff, D. Stoll, and P. W. Carr, Zirconia Stationary Phases for Extreme Separations, Anal. Chem. 2001, 73, 599A. 

A number of stationary phases are suitable for coupling on-line with MS, including RP, NP, and graphitized carbon (refer to Section III). 

B. J. Clark, Resolution of chiral compounds by HPLC using mobile phase additives and a porous graphitic carbon stationary phase, J. Pharm. Biomed. Anal., 7 1883-1888 (1989). 

J.-P. Mercier, Ph. Morin, M. Dreux and A. Tambute, Liquid chromatography analysis of phosphonic acids on porous graphitic carbon stationary phase with evaporative light-scattering and mass spectrometry detection, J. Chromatogr. A, 849, 197-207 (1999). 

Chaimbault, R et al. Ion pair chromatography on a porous graphitic carbon stationary phase for the analysis of 20 underivatized protein amino acids. J. Chromatogr. A. 2000,... 

Rinne, S. et al. Limitations of porous graphitic carbon as stationary phase material in the determination of catecholamines. J. Chromatogr. A. 2006, 1119, 285-293. 

Chambers, S.D. and Lucy C.A. Surfactant-coated graphitic carbon-based stationary phases for anion-exchange chromatography. J. Chromatogr. A. 2007, 1176, 178-184. 

Many porous organic polymers are derived from the stationary phase used to pack GC columns. Tenax is one such example. This is a macroporous polymer obtained from diphenyl p-phenylene oxide (DPPO). Generally, this polymer is hydrophobic and does not retain water. However, it exhibits some ability to adsorb polar compounds. As a result of its low surface area (30 m /g), its adsorption capacity is limited and very volatile compounds are not trapped. Therefore, it is an appropriate material for trapping heavier compounds with more than four carbon atoms. Co-precipitated graphitized carbon black and Tenax (in the proportion 23 % to 77 %) was introduced on the market as Tenax GR. This adsorbent combines the advantages of both materials and is approximately twice as effective as Tenax TA [50]. 

I. Clarot, D. Cledat, S. Battu, and P. J. P. Cardot, Chromatographic study of terpene derivatives on porous graphitic carbon stationary phase with P-cyclodextrin as mobile phase modifier, J. Chromatogr. A 903 (2000), 67. 

Polydivinylbenzene and polystyrene polymer based stationary phases also eliminate these effects. Porous graphitic carbon provides a highly non-polar surface with excellent chemical stability under acidic and basic conditions. However, they suffer from lower sample loading capacity and lower efficiency than conventional columns. 

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