Silica Gel-based Stationary Phase Materials

Many manufacturers sell the same types of stationary phase materials,6 but the most popular stationary phase materials, e.g. octadecyl-bonded silica gels, from different sources, even from the same manufacturer, often demonstrate different retention capacities and selectivities. Such differences are due to the aggressive reactivity of the silylation method and the different bonding reactions that are used, as described earlier. 

The selectivity differences can be understood by the comparison of four octadecyl-bonded silica (ODS) phases synthesized from the same silica gel. The 

Columns. ODS-silica, YMC ODS, 15 cm x 6.0 mm i.d., phenyl-bonded silica gel, YMC phenyl, 10 cm x 6.0 mm i.d. eluent, aqueous acetonitrile. Compounds, x, polycyclic aromatic hydrocarbons O, alkylbenzenes O,polychlorobenzenes +, alkanols A, alkanes 1, benzene 2, benzopyrene 3, toluene 4, heptylbenzene 5, hexachlorobenzene 6, hexanol 7, tetra-decanol 8, pentane and 9, octane. 

Preparation, Testing, and Selectivity of Stationary Phase Materials 

The best octyl- and octadecyl-bonded silica gels should be chemically stable in highly basic solutions. The well-bonded phases give good results in the inertness 

---

The disposal of used stationary phase materials, especially those used for biomedical applications, should also be of concern. Silica gel-based stationary phase materials can be heated at high temperature before disposal, and organic polymer-based stationary phase materials can be burned. Take care. 

---