Patent ID: 7563367

Claim:
A pH stable chromatographic media comprising a porous silica gel sorbent, wherein the silica gel sorbent has been chemically modified by surface polycondensation of an inorganic/organic modifier comprising the steps: a. reacting the anhydrous silica gel sorbent with the inorganic/organic modifier, wherein the modifier has the formula R 1 a R 2 b SiX 4-a-b or R (R 1 a SiX 3-a ) n , wherein R is a substituted aliphatic, cyclic, arylic or aromatic organic moiety containing 1 to 8 carbon atoms or an unsubstituted aliphatic, cyclic, arylic or aromatic organic moiety containing 1 to 8 carbon atoms, R 1 and R 2 are organic ligands containing 1 to 4 carbon atoms, X is a leaving group attached to the silicon atom, a and b are positive integers equal to 0 or 1, a plus b equals to 1 or 2 but never 0, and n is a positive integer between 2 to 8; b. hydrolyzing any unreacted leaving groups to create silanol groups; and c. dehydrating the sorbent to promote polycondensation, wherein steps a, b, and c are performed 2 to 15 times.