HPLC-CUPRAC Post-Column Derivatization Method for the Determination of Antioxidants: A Performance Comparison Between Porous Silica and Core-Shell Column Packing

Background: An HPLC method employing a post-column derivatization strategy using the cupric reducing antioxidant capacity reagent (CUPRAC reagent) for the determining antioxidants in plant-based materials leverages the separation capability of regular HPLC approaches while allowing for detection specificity for antioxidants. Methods: Three different column types, namely core-shell and porous silica including two chemically different core-shell materials (namely phenyl-hexyl and C18), were evaluated to assess potential improvements that could be attained by changing from a porous silica matrix to a core-shell matrix. Tea extracts were used as sample matrices for the evaluation specifically looking at catechin and epigallocatechin gallate (EGCG). Results: Both the C18 and phenyl-hexyl core-shell columns showed better performance compared to the C18 porous silica one in terms of separation, peak shape, and retention time. Among the two core-shell materials, the phenyl-hexyl column showed better resolving power compared to the C18 column. Conclusions: The CUPRAC post-column derivatization method can be improved using core-shell columns and suitable for quantifying antioxidants, exemplified by catechin and EGCG, in tea samples

Design and Synthesis of a New Class of Twin-Chain Amphiphiles for Self-Assembled Monolayer-based Electrochemical Biosensor Applications

A new class of twin-chain hydroxyalkylthiols (mercaptoalkanols) featuring a nearly constant cross-section and the potential for modification of one or both termini are available with complete regioselectivity through Pd-mediated couplings of benzene diiododitriflate, including an example of a previously unreported coupling to generate an ortho-substituted arene bis acetic acid. Selfassembled monolayers (SAMs) prepared from the new amphiphiles demonstrate improved stability in an electrochemical sensor system compared with monolayers prepared from analogous single chain thiols

Design and Synthesis of a New Class of Twin-Chain Amphiphiles for Self-Assembled Monolayer-based Electrochemical Biosensor Applications

A new class of twin-chain hydroxyalkylthiols (mercaptoalkanols) featuring a nearly constant cross-section and the potential for modification of one or both termini are available with complete regioselectivity through Pd-mediated couplings of benzene diiododitriflate, including an example of a previously unreported coupling to generate an ortho-substituted arene bis acetic acid. Selfassembled monolayers (SAMs) prepared from the new amphiphiles demonstrate improved stability in an electrochemical sensor system compared with monolayers prepared from analogous single chain thiols

HPLC-CUPRAC post-column derivatization method for the determination of antioxidants: a performance comparison between porous silica and core-shell column packing

Abstract Background An HPLC method employing a post-column derivatization strategy using the cupric reducing antioxidant capacity reagent (CUPRAC reagent) for the determining antioxidants in plant-based materials leverages the separation capability of regular HPLC approaches while allowing for detection specificity for antioxidants. Methods Three different column types, namely core-shell and porous silica including two chemically different core-shell materials (namely phenyl-hexyl and C18), were evaluated to assess potential improvements that could be attained by changing from a porous silica matrix to a core-shell matrix. Tea extracts were used as sample matrices for the evaluation specifically looking at catechin and epigallocatechin gallate (EGCG). Results Both the C18 and phenyl-hexyl core-shell columns showed better performance compared to the C18 porous silica one in terms of separation, peak shape, and retention time. Among the two core-shell materials, the phenyl-hexyl column showed better resolving power compared to the C18 column. Conclusions The CUPRAC post-column derivatization method can be improved using core-shell columns and suitable for quantifying antioxidants, exemplified by catechin and EGCG, in tea samples