Deep eutectic solvents (DESs) play important roles in the extraction of active constituents in traditional Chinese medicine. Ultrasound-assisted DES has been used to extract flavonoids from . Using the contents of scutellarin, baicalin, baicalein, wogonoside, wogonin, and oroxylin A as quantitative indices, different kinds of DESs have been optimized for extraction and betaine/acetic acid has shown the highest yield.
View Article and Find Full Text PDFCovalent organic frameworks with tunable porous crystallinity and outstanding stability have recently exhibited fascinating pretreatment performance as solid-phase microextraction coatings. In this report, a β-ketoenamine-linked covalent organic framework (TpPa-1) was successfully constructed through a Schiff-base-type reaction between 1,3,5-triformylphloroglucinol (Tp) and para-phenylenediamine (Pa-1). A TpPa-1 coating was then fabricated on a stainless-steel fiber for capturing trace synthetic musks.
View Article and Find Full Text PDFA new amino-modified Scholl-coupling mesoporous polymer (NH@SMPA)-online solid-phase extraction method, coupled with high-performance liquid chromatography (online SPE-HPLC) was established for the analysis of six plant growth regulators (PGRs) in bean sprouts. NH@SMPA was synthesized by acid-catalyzed deacetylation of acetylamino-Scholl-coupling mesoporous polymer (SMPA). The diversity of functional groups, such as aromatic, acetylamino, and NH, was conducive to multiple binding interactions between NH@SMPA and PGRs.
View Article and Find Full Text PDFLiAl hydrotalcite-like compound (LiAl HTlc) was synthesized via a hydrothermal method and used to adsorb Cu and Zn for investigating the adsorption characteristics of heavy metal cations. The X-Raydiffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscopy (TEM) characterizations revealed the interconnecting flower-like layered structure of LiAl HTlc. The adsorption kinetics and isotherms of Cu and Zn on LiAl HTlc agreed with the pseudo-second-order model and the Langmuir model at a given sorbent concentration (C), respectively.
View Article and Find Full Text PDFDisinfection by-products (DBPs) in drinking water can pose a health risk to humans. In this work, a new nitrogen-rich covalent organic frameworks (TpTt-COFs) was synthesized and applied firstly as a novel solid-phase extraction (SPE) trapping media for four ultra-trace levels of DBPs in drinking water samples. Under the optimal conditions, these DBPs were absorbed on a SPE cartridge; then, the DBPs were eluted with the optimized volume of eluent.
View Article and Find Full Text PDFHigh-performance capturing polar phenoxycarboxylic acids herbicides (PCAs) from water samples remains a great challenge because PCAs form salt easily and dissolve. Polyphenylene-based conjugated microporous polymers (PP-CMPs), a fascinating type of polymers, bear π-conjugation over 3D polyphenylene scaffolds, inherent micropore, and large surface area, which are essential for capturing trace PCAs in complex samples. This work developed a novel approach to quantify trace PCAs using PP-CMPs as an efficient dispersive solid-phase extraction (d-SPE) adsorbent.
View Article and Find Full Text PDFFive iridoid glycosides were prepared using molecularly imprinted solid-phase extraction combined with preparative high-performance liquid chromatography. Hydrophilic molecularly imprinted polymers were synthesized using α-1-allyl-2-N-acetyl glucosamine, which introduced an abundance of hydrophilic groups into the polymers. Using molecularly imprinted solid-phase extraction as the sample pretreatment procedure, five iridoid glycosides, gardenoside, geniposide, shanzhiside, geniposidic acid, and genipin-1-O-gentiobioside, were selectively enriched from Gardenia fructus extracts.
View Article and Find Full Text PDFHydrophilic molecularly imprinted polymers (H-MIP) with molecular recognition ability for iridoid glycosides (IGs) have been obtained via bulk polymerization combined with hydrolysis of ester groups. H-MIP were characterized by Fourier transform infrared spectroscopy (FT-IR). The hydrophilcity was measured by the contact angle measurement and the water dispersion stability.
View Article and Find Full Text PDFIn recent years, bamboo charcoal, a new kind of material with special microporous and biological characteristics, has attracted great attention in many application fields. In this paper, the potential of bamboo charcoal to act as a solid-phase extraction (SPE) adsorbent for the enrichment of the environmental pollutant perfluorooctanoic acid, which is one of the newest types of persistent organic pollutants in the environment, has been investigated. Important factors that may influence the enrichment efficiency--such as the eluent and its volume, the flow rate of the sample, the pH of the sample and the sample volume--were investigated and optimized in detail.
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