Silica-supported Polymeric Monolithic Column With A Mixed Mode Of Hydrophilic And Strong Cation-exchange Interactions For Microcolumn Liquid Chromatography

The present paper presents a silica-particle-supported polymeric monolithic column with a mixed mode of hydrophilic and strong cation-exchange interactions(shortened as the supported column;S-column).The procedure was composed of two major steps,i.e.(i)preparation of silica-particles-supported poly(GMA-co-PETA)monolithic matrix(S-matrix)in the binary solvent consisting of methanol and cyclohexanol.By tuning the polarity of the solvent and the total concentration of the monomers,a thin layer of the polymers was formed only on the particle surface in the form of nanoglobules,leaving the interstitial space free for eluent flow and(ii)introduction of SAGs onto the S-matrix by treating with Na₂SO₃ inside a150-?m I.D.capillary.The preparation conditions were investigated with respect to porogen composition,the monomer concentration,polymerization time,Na₂SO₃ solution p H,sulfonation time,and the method was described in detail.The prepared column was characterized in terms of structural homogeneity and pore size uniformity,mechanical stability,permeability,swelling-shrinking behavior,hydrophilicity,binding capacity and column efficiency etc.The swelling–shrinking behavior of the present column in solvents of different polarities was negligible,the hydrophobicity could be suppressed at the ACN concentrations higher than 40%v/v,and the binding capacities were 256?equiv/m L and 20.1 mg/m L for Cu²⁺and lysozyme,respectively.The minimum theoretical plate heights were 8,10,and 13?m,and the values of the C term in van Deemter equation were 9,12,and 35 ms for the test analytes of Na+,thiourea,and cytidine 5?-monophosphate,respectively.Finally,three monovalent inorganic cations achieve the rapid baseline separation on the S-column based on the strong exchange mode.A phenol mixture and an amide mixture were baseline separated on the S-column based on hydrophilic retention mechanism.Fast baseline separation of four nucleotides was achieved on a short S-column based on mixed-mode of hydrophilic and strong cation exchange interactions.