Page 166 - Applied Pharmacognosy
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What is inside the column-The stationary phase
Silica Gel as Stationary Phase or as Support
❑ A silica surface has up to 8 mmol of silanol groups (Si-OH)/m2.
❑ Most silica cannot be used above pH 8, pH range 2–8
because it dissolves in base.
❑ The siloxane (Si-O-Si) bond hydrolyzes below pH 2.
Bare silica can be used as St. phase for adsorption chromatogra1p65hy
