Reversed-phase chromatography surface chemistries used

Obviously, the monolithic material may serve its purpose only if provided with a suitable surface chemistry, which depends on the desired application. For example, hydrophobic moieties are required for reversed phase chromatography, ionizable groups must be present for separation in the ion-exchange mode, and chiral functionalities are the prerequisite for enantioselective separations. Several methods can be used to prepare monolithic columns with a wide variety of surface chemistries. 

An overview and discussion is given of literature methods published after 1989 devoted to the ion-interaction chromatographic determination of inorganic anions. Seventy references are quoted. Ion-interaction chromatography makes use of commercial reversed-phase stationary phase and conventional high-performance liquid chromatography instrumentation. The basis of the technique, the modification of the stationary phase surface, the choice of the ion-interaction reagent as well as the dependence of retention on the different variables involved are discussed. Examples of application in the fields of environmental, clinical and food chemistry are presented. The experimental conditions of stationary phase, of mobile phase composition as well as detection mode, detection limit and application are also summarized in tables. 1997 Elsevier Science B.V. 

The complex surface chemistry of the metal oxides (section 4.2.1.2) is incompatible with their use in a number of chromatographic techniques. Polymer coated metal oxides are seen as an important approach to extending their scope. Alumina and zirconia particles coated with poly(butadiene), poly(styrene), poly(ethylene oxide), a copolymer of chloromethylstyrene and diethoxymethylvinylsilane and succinylated poly(ethyleneimine), for example, have been prepared for use in reversed-phase, size-exclusion and ion-exchange chromatography [44,46,54,120,134-137]. The methods of preparation are similar to those used for porous silica. 

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