Parallel enrichment of polyphenols and phytosterols from Pinot noir grape seeds with molecularly imprinted polymers and analysis by capillary high-performance liquid chromatography electrospray ionisation tandem mass spectrometry.

This investigation describes an integrated workflow for the parallel extraction and recovery of polyphenols and phytosterols from Pinot noir grape seeds. Using (E)-resveratrol and stigmasterol as exemplars, the approach employs two different molecular imprinted polymers in tandem for the extraction of these compounds and their subsequent analysis by capillary high-performance liquid chromatography (capHPLC) interfaced with electrospray ionisation tandem mass spectrometry (ESI MS/MS). Information on the selectivity of the solid-phase extraction processes was obtained through analysis of the binding behaviour of (E)-resveratrol- and stigmasterol-imprinted polymers using structurally similar polyphenols or phytosterols with the extent of binding determined from the capHPLC-ion trap ESI MS/MS data.

Application of linear solvation energy relationships and principal component analysis methods for the prediction of the retention behaviour of E-resveratrol analogues with substituted silica hydride stationary phases.

In this investigation, application of linear solvent energy relationships (LSERs) and principal component analysis (PCA) methods have been employed to investigate the structure-retention dependencies of E-resveratrol analogues separated under different stationary and mobile phase conditions. To this end, the retention of 22 analogues have been determined with phenyl, diol, bidentate anchored C18 (BDC18) and Diamond Hydride™ C18 (DHC18) substituted silica hydride stationary phases under isocratic chromatographic conditions using mobile phases containing 0.1 (% v/v) formic acid and different acetonitrile or methanol contents from 10 to 90% (v/v) in 10% increments.

Design, synthesis and application of a new class of stimuli-responsive separation materials.

A new class of efficient stationary phase has been investigated for use in the liquid chromatographic separation of low molecular weight analytes and high molecular weight biomolecules, based on the application of immobilised stimuli-responsive polymers (SRPs). To this end, two polymeric units, namely poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) and poly(acrylic acid) (PAA) were tethered to a triazine core. The derived poly(2-dimethyl-aminoethyl methacrylate)-block-poly(acrylic acid) (PDMAEMA-b-PAA), as a diblock co-polymer, was then immobilised onto the surface of porous silica particles.

Selectivity mapping of the binding sites of (E)-resveratrol imprinted polymers using structurally diverse polyphenolic compounds present in Pinot noir grape skins.

This investigation describes a general procedure for the selectivity mapping of molecularly imprinted polymers, using (E)-resveratrol-imprinted polymers as the exemplar, and polyphenolic compounds present in Pinot noir grape skin extracts as the test compounds. The procedure is based on the analysis of samples generated before and after solid-phase extraction of (E)-resveratrol and other polyphenols contained within the Pinot noir grape skins using (E)-resveratrol-imprinted polymers. Capillary reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionisation tandem mass spectrometry (ESI MS/MS) was then employed for compound analysis and identification.

Recovery of ergosterol from the medicinal mushroom, Ganoderma tsugae var. Janniae, with a molecularly imprinted polymer derived from a cleavable monomer-template composite.

A semi-covalent imprinting strategy has been developed for the synthesis of molecularly-imprinted polymers specific for the fungal sterol, ergosterol, a biological precursor of vitamin D. This imprinting approach involved a novel post-synthesis cleavable monomer-template composite, namely ergosteryl methacrylate, and resulted in the formation of an imprinted polymer that selectively and efficiently recognized ergosterol through non-covalent interactions. The derived molecularly-imprinted polymer and the corresponding non-imprinted polymer were systematically evaluated for their selectivity towards ergosterol via static and dynamic binding studies using various ergosteryl esters (e.

Application of pH-responsive poly(2-dimethyl-aminoethylmethacrylate)-block-poly(acrylic acid) coatings for the open-tubular capillary electrochromatographic analysis of acidic and basic compounds.

A new type of stimuli-responsive polymeric (SRP) coating has been prepared for use in open tubular capillary electrochromatography (OT-CEC), by grafting poly(2-dimethylaminoethylmethacrylate)-block-poly(acrylic acid) (PDMAEMA-b-PAA) as a Y-shaped block copolymer with two dissimilar chain compositions onto the inner walls of aminopropyl-modified silica capillaries. The grafting process introduced weakly charged functional groups from the PAA and PDMAEMA, enabling the generation of electroendosmotic flow with magnitude and direction adjustable by changing the pH of the running buffer electrolyte. This stimuli-responsive PDMAEMA-b-PAA block copolymer was found to provide excellent resolution of various acidic and basic compounds, leading to efficient analyte separation.

Sequential molecularly imprinted solid-phase extraction methods for the analysis of resveratrol and other polyphenols.

Molecularly imprinted polymers (MIPs) templated with either the phytoalexin, (E)-resveratrol, or its structural analog, 3,5-dihydroxy-N-(4-hydroxyphenyl)benzamide, have been used in tandem for the sequential extraction of (E)-resveratrol from aqueous peanut meal extracts in high purity and in near quantitative yields. Re-processing of the (E)-resveratrol-depleted peanut meal extract with the 3,5-dihydroxy-N-(4-hydroxyphenyl)benzamide imprinted MIP yielded additional polyphenolic components, identified as A-type procyanidins. Tandem liquid chromatography-electrospray ionization mass spectrometry confirmed the identity and purity of the isolated products.

The Application of Template Selectophores for the Preparation of Molecularly Imprinted Polymers.

Molecularly imprinted polymers are versatile materials with wide application scope for the detection, capture and separation of specific compounds present in complex feed stocks. A major challenge associated with their preparation has been the need to sacrifice one mole equivalent of the template molecule to generate the complementary polymer cavities that selectively bind the target molecule. Moreover, template molecules can often be difficult to synthesise, expensive or lack stability.

A comparison of covalent and non-covalent imprinting strategies for the synthesis of stigmasterol imprinted polymers.

Non-covalent and covalent imprinting strategies have been investigated for the synthesis of stigmasterol imprinted polymers. The synthesized molecularly imprinted polymers (MIPs) were then evaluated for their recognition and selectivity towards stigmasterol via static and dynamic batch-binding assays and their performance measured against control non-imprinted polymers (NIPs). MIPs prepared using the conventional non-covalent imprinting method displayed little to no binding affinity for stigmasterol under various conditions.

Rapid solid-phase extraction and analysis of resveratrol and other polyphenols in red wine.

Red wine has long been credited as a good source of health-beneficial antioxidants, including the bioactive polyphenols catechin, quercetin, and (E)-resveratrol. In this paper, we report the application of reusable molecularly imprinted polymers (MIPs) for the selective and robust solid-phase extraction (SPE) and rapid analysis of (E)-resveratrol (LOD=8.87×10(-3) mg/L, LOQ=2.

Preparation of molecularly imprinted polymers for the selective recognition of the bioactive polyphenol, (E)-resveratrol.

(E)-Resveratrol imprinted polymers have been rationally designed with the aid of molecular modelling and NMR spectroscopic titration techniques to determine the optimal ratio of the template to functional monomer for polymer formation. Based on this approach, (E)-resveratrol imprinted polymers were prepared via non-covalent self-assembly with the functional monomer 4-vinylpyridine (4VP) in a 1:3 molar ratio. Polymerisation in the presence of a cross-linker resulted in rigid block copolymers that had selective capacities towards (E)-resveratrol (e.

Enrichment of (E)-resveratrol from peanut byproduct with molecularly imprinted polymers.

Molecularly imprinted solid phase extraction (MISPE) has been employed to isolate and concentrate bioactive polyphenols from peanut press waste. To this end, a molecularly imprinted polymer (MIP) templated with the phytoalexin (E)-resveratrol has been prepared via self-assembly with the functional monomer 4-vinylpyridine (4VP) in a 1:3 molar ratio. Subsequent molecular interrogation of the MIP binding sites demonstrated preferential structural selectivity for (E)-resveratrol with respect to other structurally related naturally occurring compounds.