Hydroxyapatite surface-functionalized monolithic column for selective in-tube solid phase microextraction of zoleronic acid and risedronic acid.

To date, hydroxyapatite (HAP) based monoliths were mainly fabricated by directly doping of HAP, which suffered from less effective coverage of HAP. Herein, a HAP surface-functionalized monolithic column (HAP@PDA@UF) has been prepared by in-situ biomineralization and applied as sorbent for selective in-tube solid phase microextraction of zoleronic acid and risedronic acid. A polydopamine coating was first generated on the surface of the parent urea-formaldehyde resin monolith; and then HAP microcrystals were further grew on the polydopamine coating to achieve this preparation.

Sulfonate-bonded covalent organic polymer as mixed-mode sorbent for on-line solid-phase extraction of ß-receptor agonists.

A novel sulfonate-bonded covalent organic polymer (COP@SA) with mixed-mode interactions of hydrophobic and cation-exchange was synthesized and exploited as sorbent for on-line solid-phase extraction (on-line SPE) of ß-receptor agonists. The successful synthesis of COP@SA was confirmed by the characterization of SEM, XPS and FT-IR. Due to the excellent mixed-mode extraction ability towards the positively charged ß-receptor agonists and the good anti-interference performance, COP@SA was introduced into on-line SPE-HPLC system for selective extraction of ß-receptor agonists in pork and pork liver.

Hydroxyapatite-embedded monolithic column for selective on-line solid-phase extraction of adenosine triphosphate and its phosphorylated metabolites.

A novel hydroxyapatite-embedded monolithic column has been facilely prepared in a stainless-steel column with inner diameter of 2.1 mm by the strong adhesion of urea-formaldehyde (UF) resin and exploited as a sorbent for selective on-line solid-phase extraction (on-line SPE) of adenosine triphosphate and its phosphorylated metabolites. The composition for this preparation, including the amount of hydroxyapatite nanopowders and the porogen were investigated to obtain a suitable monolith with large surface area and satisfactory permeability.

Poly (Octadecyl Methacrylate-Co-Trimethylolpropane Trimethacrylate) Monolithic Column for Hydrophobic in-Tube Solid-Phase Microextraction of Chlorophenoxy Acid Herbicides.

Chlorophenoxy acid herbicides (CAHs), which are widely used on cereal crops, have become an important pollution source in grains. In this work, a highly hydrophobic poly (octadecyl methacrylate-co-trimethylolpropane trimethacrylate) [poly (OMA-co-TRIM)] monolithic column has been specially prepared for hydrophobic in-tube solid-phase microextraction (SPME) of CAHs in rice grains. Due to the hydrophobicity of CAHs in acid conditions, trace CAHs could be efficiently extracted by the prepared monolith with strong hydrophobic interaction.