Base Material Silica, Zirconia, Alumina, Polymers

2 TYPE OF PACKING MATERIAL (POROUS, NONPOROUS, MONOLITHIC) [Pg.77]

Majority of packing materials used in HPLC are porous particles with average diameters between 3 and 10 pm. For most pharmaceutical applications, 3-pm particle sizes are recommended. Porosity provides the surface area necessary for the analyte retention (usually between 100 and 400m /g). Interparticle space is large enough to allow up to 1-3 mL/min flow within acceptable pressure range (however, the pressure drop across the column depends on the particle size, length of column, temperature of separation, and type of mobile-phase composition). [Pg.77]

In modem liquid chromatography, almost all reversed-phase separations are performed on chemically modified adsorbents. Analyte interactions with the [Pg.77]

Stationary phase surface are the primary factor for successful separations. Most commercial adsorbents reflect their surface chemistry in their names (e.g., C18, C8, Phenyl, etc.) while the base material used usually is not specihed, although its properties are very important. [Pg.78]

Surface area is directly related to the analyte retention [Equation (2-47) in Chapter 2], Generally, the higher the surface area, the greater the retention. [Pg.78]

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