Characterisation of important interactions controlling retention behaviour of analytes in reversed-phase high-performance liquid chromatography

Microcalorimetric Studies on the Interaction Mechanism between Proteins and Hydrophobic Solid Surfaces in Hydrophobic Interaction Chromatography: Effects of Salts, Hydrophobicity of the Sorbent, and Structure of the Protein

“…Since the Toyopearl butyl and phenyl sorbents have similar ligand densities, this observation reflects differences in the strength of the hydrophobic interactions. Although the Toyopearl phenyl sorbent has the opportunity to bind to exposed aromatic side-chain groups on the surface of HEWL through interactions based on induced dipole and π−π interactions, − this does not, however, mean that a higher affinity will necessarily be obtained for the Toyopearl phenyl sorbent compared to the Toyopearl butyl sorbents with HEWL, as shown in Figure . This result is in agreement with the observation of Stocchi and co-workers, who demonstrated that the Toyopearl 650 M butyl sorbent has a higher retention for proteins than the Toyopearl 650 M phenyl sorbent.…”

“…[11][12][13][14][15] Compared to n-alkyl-based HIC sorbents, the interactions between proteins and HIC sorbents containing aromatic groups such as phenyl or benzyl ligands have followed less predictable binding behavior, and this has been attributed to the participation of π-π interactions. [16][17][18][19] With aryl-based HIC sorbents, this type of interaction also involves the interplay of Lifschitz-London forces between π-electron-containing compounds such as aromatic rings, in which one moiety is electronrich (π-basic group or π-electron donor) and the other is electronpoor (π-acidic group or π-electron acceptor). In this context, two types of the forces can be defined, i.e., face-to-edge and face-toface (also called π-stacking) π-π interactions.…”

“…Other investigations with n -alkyl agarose sorbents revealed that the strength of the hydrophobic interactions increases with the hydrophobicity (ligand chain length, type, density) of the HIC sorbents. − Compared to n -alkyl-based HIC sorbents, the interactions between proteins and HIC sorbents containing aromatic groups such as phenyl or benzyl ligands have followed less predictable binding behavior, and this has been attributed to the participation of π−π interactions. − With aryl-based HIC sorbents, this type of interaction also involves the interplay of Lifschitz−London forces between π-electron-containing compounds such as aromatic rings, in which one moiety is electron-rich (π-basic group or π-electron donor) and the other is electron-poor (π-acidic group or π-electron acceptor). In this context, two types of the forces can be defined, i.e., face-to-edge and face-to-face (also called π-stacking) π−π interactions. − These forces can be exploited in conjunction with hydrogen-bonding effects to separate similar biomolecules based on molecular recognition phenomena, such as those arising in HIC or with molecularly imprinted polymers. − Although the contributions of hydrophobic forces involving π−π interactions were initially expected to result in higher binding strengths with proteins in HIC systems, the converse was obtained with the retention of proteins onto HIC sorbents such as the Toyopearl butyl sorbent stronger than that with the corresponding Toyopearl phenyl sorbent.…”

A cyanopropyl reversed phase chromatography enables resolution of huperzine A and B on analytical and preparative scales

“…Inertsil CN-3, a cyanopropyl (CN) column from the same manufacturer of the C18 column, was able to give excellent baseline separation of HupA and HupB with a simple mobile phase consisting of methanol and water. Hydrophobic interactions are considered as major factors that contribute to retention behavior in RPC, whereas other minor interactions, such as dipole -dipole interactions, hydrogen bond formation, and p-p interactions often determine the separation of closely related compounds [19]. For the nonpolar C18 column, the low selectivity probably resulted from the fact that C18 might not be a suitable ligand for the separation of HupA and HupB, which are complex molecules with close hydrophobicity.…”

Sorption mechanism and prediction of sorbents' behaviour in physicochemical systems

“…179 ± 181 One aims to determine the values DF regarding the resulting interaction of the sorbate and sorbent as a sum of interactions of different types, by considering their influence to be additive. 182 For example, the dispersion, dipole, and pairwise electronic interactions are discriminated while describing sorption. 183 However, more precise information about the interaction potentials of atoms is required in such a method.…”