Sulfonate-bonded covalent organic polymer as mixed-mode sorbent for on-line solid-phase extraction of ß2-receptor agonists

Hydroxylated hierarchical flower-like COF for solid-phase extraction of adrenergic receptor agonists in milk

A new detection platform based on a hydroxylated covalent organic framework (COF) integrated with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was constructed and used for detecting adrenergic receptor agonists (ARAs) residues in milk. The hydroxylated COF was prepared by polymerization of tris(4-aminophenyl)amine and 1,3,5-tris(4-formyl-3-hydroxyphenyl)benzene and applied to solid-phase extraction (SPE) of ARAs. This hydroxylated COF was featured with hierarchical flower-like morphology, easy preparation, and copious active adsorption sites. The adsorption model fittings and molecular simulation were applied to explore the potential adsorption mechanism. This detection platform was suitable for detecting four α2- and five β2-ARAs residues in milk. The linear ranges of the ARAs were from 0.25 to 50 µg·kg-1; the intra-day and the inter-day repeatability were in the range 2.9-7.9% and 2.0-10.1%, respectively. This work demonstrates this hydroxylated COF has great potential as SPE cartridge packing, and provides a new way to determine ARAs residues in milk.

One-pot synthesis of magnetic sulfonated covalent organic polymer for extraction of protoberberine alkaloids in herbs and human plasma

A novel magnetic sulfonated covalent organic polymer was prepared for magnetic solid-phase extraction of protoberberine alkaloids. The magnetic sulfonated covalent organic polymer was rapidly synthesized under mild conditions. The physicochemical properties of the prepared materials were characterized by Fourier-transform infrared spectrometry, transmission electron microscopy, and X-ray photoelectron spectroscopy. Several extraction parameters were systematically investigated, including desorption time, pH of sample solution, acetonitrile content, acetic acid content in the eluent, extraction time, and sample volume. By coupling magnetic solid-phase extraction and high-performance liquid chromatography, an efficient and sensitive method for the extraction and determination of protoberberine alkaloids in complex samples was developed. The proposed method showed great linearity (r > 0.9989), low limits of detection (0.2-0.3 ng/ml), and high precision (relative standard deviations ≤ 5.74%). The proposed method was further applied to the analysis of protoberberine alkaloids in Cortex phellodendri and human plasma samples. The recoveries were 91.50%-110.31% with relative standard deviations less than 6.63% in Cortex phellodendri and 96.12%-111.20% with relative standard deviations lower than 5.56% in plasma samples.

On-line separation/analysis of Rhodamine B dye based on a solid-phase extraction high performance liquid chromatography self-designed device

A special self-designed device based on poly-1-vinyl-3-pentylimidazole hexafluorophosphate (PILs-C5) solid-phase extraction and high performance liquid chromatography (HPLC) is proposed as a novel method for the on-line separation and analysis of Rhodamine B (RhB) dye. Single factor experiment design and orthogonal experiment design were used to optimize the experimental parameters, such as pH, the amount of PILs-C5, sample volume, flow rate, eluent type, eluent concentration, eluent volume, and the flow rate of eluent. Under the optimized conditions, the linear range was 0.02-2.4 μg mL-1, with the correlation coefficients (R 2) of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were 0.004 μg mL-1 and 0.02 μg mL-1, respectively. The extraction capacity was 6.22 mg g-1, and enrichment ratio was 15. The extraction mechanism and the post-treatment method of PILs-C5 were also studied. This method was applied to analyze RhB in a wide variety of real samples with satisfactory results.