Innovative method for the enrichment of high-polarity bioactive molecules present at low concentrations in complex matrices

Preparation and evaluation of photo-responsive hollow SnO2 molecularly imprinted polymers for the selective recognition of kaempferol

Novel photo-responsive hollow structured molecularly imprinted polymers (PHMIPs) were developed as a selective sorbent to recognize and separate analytes in complex samples. The PHMIPs were prepared using kaempferol (KAE) as the template, 4-[(4-methacryloyloxy) phenylazo] benzenesulfonic acid as a photo-responsive functional monomer, and hollow SnO₂ (Ho-SnO₂) as the support via free radical polymerization. The structure and physical properties of the developed polymers were characterized using different nano structural techniques and spectroscopy. Under alternating irradiation at 365 and 440 nm, the PHMIPs could release and uptake KAE, indicating that the template molecules can be easily bound to recognition sites and released back into solution. From adsorption experiments, the binding properties were evaluated, and the maximal adsorption capacity of the PHMIPs was 11.04 mg g^-1. Furthermore, the developed PHMIPs showed high selectivity towards KAE compared to other compounds. Subsequently, the materials were successfully applied to the photo-controlled extraction of KAE from sea buckthorn leaves. The recoveries for KAE were higher than 90% and relative standard deviation values were between 1.81% and 2.53%, indicating the potential of the developed materials for use in extracting KAE from complex samples.

Trace determination and characterization of ginsenosides in rat plasma through magnetic dispersive solid-phase extraction based on core-shell polydopamine-coated magnetic nanoparticles

Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging. This study presented a one-pot synthesis of magnetic polydopamine nanoparticles (Fe₃O₄@SiO₂@PDA NPs) with multiple recognition sites for the magnetic dispersive solid-phase extraction (MDSPE) of ginsenosides from rat plasma treated with white ginseng. The extracted ginsenosides were characterized by combining an ultra-high-performance liquid chromatography coupled to a high-resolution mass spectrometry with supplemental UNIFI libraries. Response surface methodology was statistically used to optimize the extraction procedure of the ginsenosides. The reusability of Fe₃O₄@SiO₂@PDA NPs was also examined and the results showed that the recovery rate exceeded 80% after recycling 6 times. Furthermore, the proposed method showed greater enrichment efficiency and could rapidly determine and characterize 23 ginsenoside prototypes and metabolites from plasma. In comparison, conventional methanol method can only detect 8 ginsenosides from the same plasma samples. The proposed approach can provide methodological reference for the trace determination and characterization of different bioactive ingredients and metabolites of traditional Chinese medicines and food.

•

The Fe₃O₄@SiO₂@PDA NPs were synthesized through one-pot method.

•

The RSM was designed to promote the extraction of trace active ingredients.

•

The MDSPE, UPLC-MS and UNIFI software were integrated into an analytical platform.

•

The synergetic strategy was applied to enrich ginsenosides from rat plasma.

•

The synergetic strategy provided an easy, rapid and sensitive method for analytes.

The Multi-Template Molecularly Imprinted Polymer Based on SBA-15 for Selective Separation and Determination of Panax notoginseng Saponins Simultaneously in Biological Samples

The feasible, reliable and selective multi-template molecularly imprinted polymers (MT-MIPs) based on SBA-15 (SBA-15@MT-MIPs) for the selective separation and determination of the trace level of ginsenoside Rb₁ (Rb₁), ginsenoside Rg₁ (Rg₁) and notoginsenoside R₁ (R₁) simultaneously from biological samples were developed. The polymers were constructed by SBA-15 as support, Rb₁, Rg₁, R₁ as multi-template, acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The new synthetic SBA-15@MT-MIPs were satisfactorily applied to solid-phase extraction (SPE) coupled with high performance liquid chromatography (HPLC) for the separation and determination of trace Rb₁, Rg₁ and R₁ in plasma samples. Under the optimized conditions, the limits of detection (LODs) and quantitation (LOQs) of the proposed method for Rb₁, Rg₁ and R₁ were in the range of 0.63⁻0.75 ng·mL-1 and 2.1⁻2.5 ng·mL-1, respectively. The recoveries of R₁, Rb₁ and Rg₁ were obtained between 93.4% and 104.3% with relative standard deviations (RSDs) in the range of 3.3⁻4.2%. All results show that the obtained SBA-15@MT-MIPs could be a promising prospect for the practical application in the selective separation and enrichment of trace Panax notoginseng saponins (PNS) in the biological samples.