Patent ID: 8568594

Claim:
A chromatographic method comprising the steps of: loading a sample potentially comprising an analyte onto a mixed-mode chromatographic sorbent, wherein the analyte comprises a modified peptide or a modified protein and wherein the sorbent conforms to Formula 1: (W 1 ) a (W 2 ) b (W 3 ) c Si(Z—C 6 F n H 5-n ) d Formula 1 where W 1 , W 2 , and W 3 are selected from the groups consisting of hydrogen, hydroxyl, hydroxy-aliphatic, aliphatic, oxygen, nitrogen, and silane wherein at least one of W 1 , W 2 , and W 3 separately represent terminal silane valences bonded to oxygen, nitrogen, carbon or silane atoms of a support, Z represents a aliphatic moiety and n is an integer from 1-5, and a+b+c+d=4; where a is 1-3;b+c is less than or equal to 2, and d is 1-3; eluting the mixed-mode chromatographic sorbent in reverse phase mode, thereby separating the analyte, if present, from the sample; and eluting the mixed-mode chromatographic sorbent in ion exchange mode, thereby regenerating the mixed-mode chromatographic sorbent.