Novel molecularly imprinted magnetic nanoparticles for the selective extraction of protoberberine alkaloids in herbs and rat plasma

In this work, a novel magnetic nanomaterial functionalized with a molecularly imprinted polymer was prepared for the extraction of protoberberine alkaloids. Molecularly imprinted polymers were made on the surface of Fe₃O₄ nanoparticles by using berberine as template, acetonitrile/water as porogen, acrylamide as functional monomer and ethylene glycol dimethacrylate as cross‐linker. The optimized molar ratio of template/functional monomer was 1:7. The polymeric magnetic nanoparticles were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The stability and adsorption capacity of the molecularly imprinted polymers were investigated. The molecularly imprinted polymers were used as a selective sorbent for the magnetic molecularly imprinted solid‐phase extraction and determination of jatrorrhizine, palmatine, and berberine. Extraction parameters were studied including loading pH, sample volume, stirring speed, and extraction time. Finally, a magnetic molecularly imprinted solid‐phase extraction coupled to high‐performance liquid chromatography method was developed. Under the optimized conditions, the method showed good linear range of 0.1–150 ng/mL for berberine and 0.1–100 ng/mL for jatrorrhizine and palmatine. The limit of detection was 0.01 ng/mL for berberine and 0.02 ng/mL for jatrorrhizine and palmatine. The proposed method has been applied to determine protoberberine alkaloids in Cortex phellodendri and rat plasma samples. The recoveries ranged from 87.33–102.43%, with relative standard deviation less than 4.54% in Cortex phellodendri and from 102.22–111.15% with relative standard deviation less than 4.59% in plasma.     

Selective and sensitive determination of protoberberines by capillary electrophoresis coupled with molecularly imprinted microextraction

In this work, we developed a novel molecularly imprinted solid‐phase microextraction with capillary electrophoresis method for the selective extraction and determination of protoberberines in complicated samples. The imprinted monolith was prepared in a micropipette tip‐based device by using acrylamide as the functional monomer, ethyleneglyoldimethacrylate as the cross‐linker and dimethylsulfoxide as the porogen, and exhibited an imprinting factor of 2.41 to berberine, 2.36 to palmatine and 2.38 to jatrorrhizine. Good capillary electrophoresis separation was achieved by using 20 mM phosphate buffer at pH 7 as running buffer with the addition of organic modifier of 10% methanol. Parameters such as sample pH value, sample flow rate and sample volume were investigated for imprinted monolith‐based solid‐phase microextraction. An imprinted solid‐phase microextraction with capillary electrophoresis method was developed, the method showed a wide linear range (0.3–50 μg/mL), good linearity (R² ≥ 0.9947) and good reproducibility (relative standard deviations ≤ 0.73%), the limit of detection was as low as 0.1 μg/mL, which was lower than some reported methods based on capillary electrophoresis for protoberberines. The method has been applied for determination of three common protoberberines in Cortex Phellodendri Chinensis, by using a molecularly imprinted monolith as the selective sorbent, most of the matrices in the Cortex Phellodendri Chinensis sample were removed and three protoberberines were selectively enriched and well determined.     

The total synthesis of immunostimulant α-galactosylceramides from naturally configured α-galactoside raffinose

The total synthesis of absolute anomeric confirmation α-galactosylceramide analogues from raffinose is described. Using the naturally occurring α-galactoside raffinose as the starting material, the easily maneuverable protocol without glycosylation reactions ensured the critical α-linkage in the product and simplified the synthetic procedures. The immunostimulatory activities of the new α-galactosylceramides were validated by both in vitro and in vivo NKT cell stimulation assays.     

A poly (4‐vinylpridine‐co‐ethylene glycol dimethacrylate) monolithic concentrator for in‐line concentration‐capillary electrophoresis analysis of phenols in water samples

A poly(4‐vinylpridine‐co‐ethylene glycol dimethacrylate) monolith was synthesized in a capillary and constructed as a concentrator for the in‐line polymeric monolith microextraction coupling with capillary electrophoresis. The integrated system was then used for the simultaneous determination of five trace phenols (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2‐chlorophenol, and 2,4‐dichlorophenol) in water samples. The experimental parameters for in‐line solid‐phase extraction, such as composition and volume of the elution plug, pH of sample solution, and the time for sample loading were optimized. The sensitivity for the mixture of phenols (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2‐chlorophenol, and 2,4‐dichlorophenol) enhanced to 615–2222 folds at the optimum condition was compared to the sensitivity for a normal hydrodynamic injection in capillary electrophoresis. Linearity ranged from concentration of 10–500 ng mL^?1(R² > 0.999) for all five phenols with the detection limits of 1.3–3.3 ng mL^?1. In tap, snow and Yangtze River water spiked with 20 ng mL^?1 and 200 ng mL^?1, respectively, the recoveries of 84–105% were obtained. It has been demonstrated that this work has great potential for the analysis of phenols in genuine water samples.     

Energy levels fitting and crystal-field calculations of Nd3+ doped in GYSGG crystal

The single crystal Nd³⁺-doped in GdY₂Sc₂Ga₃O₁₂ (Nd³⁺:GYSGG) was grown by Czochralski method successfully, and its absorption spectra was analyzed in a wider spectral wavelength range at 7.6 K and 300 K, respectively. The free-ions and crystal-field parameters were fitted to the experimental energy levels at 7.6 K and 300 K with the root mean square deviation of 11.25 and 12.48 cm^?1, respectively. According to the crystal-field calculations, 116 levels of Nd³⁺ at 7.6 K and 114 levels of Nd³⁺ at 300 K were assigned. The fitting results of free-ions and crystal-field parameters were compared with those already reported of Nd³⁺:GSGG and Nd³⁺:YSAG. The results indicated that the free-ions parameters are similar to those of the Nd³⁺ in GYSGG, GSGG and YSAG crystals, and the crystal-field interaction of GSGG and YSAG is stronger than that of GYSGG, which results in the dual-wavelength properties of Nd³⁺:GYSGG crystal.     

Schiff碱改性法制备SBA-15型介孔分子筛负载的纳米氧化镍

基于Schiff碱功能单体的改性作用,采用共缩聚方法,制备了SBA-15型介孔分子筛负载的氧化镍纳米粒子。 采用小角X射线散射（small angle XRD）、广角X射线衍射（wide angle XRD）、紫外-可见光谱（UV-Vis）、高分辨透射电子显微镜（HRTEM）和N2吸附-脱附测定对制得的样品进行了表征。 结果表明,制得的样品具有SBA-15型介孔分子筛典型的二维六方有序结构,NiO纳米粒子主要分布于SBA-15型介孔分子筛的孔道内。 当功能单体的含量不超过10%时,SBA-15型介孔分子筛的孔径在6~8 nm范围内;而当功能单体的含量达到15%时,SBA-15型介孔分子筛的孔道被严重堵塞,孔径降为3.8 nm。 NiO纳米粒子的尺寸随着功能单体含量的增加而增大。     

Facile synthesis of biotin-labelled α-galactosylceramide as antigen for invariant natural killer T cells

When iNKT cells are stimulated by the CD1d presented exogenous α-galactosylceramide, a myriad of cytokines are released that trigger a variety of immune responses. However, the invisibility and poor aqueous solubility of α-galactosylceramide during bioassays have rendered it difficult to study the aforementioned biological responses. Accordingly, a biotin-labelled α-galactosylceramide was prepared to facilitate detection of this antigen in the immune process. The problematic low solubility was also remedies via incorporation of a truncated acyl chain.     

多孔有机聚合物在水处理中的应用

多孔有机聚合物是一类由纯有机基团构成的新型材料。 近年来,多孔有机聚合物在吸附水中污染物方面引起了人们的兴趣。 本文简要地介绍了几种多孔有机聚合物吸附水中污染物最近的研究进展,并对其吸附机理、影响因素和研究前景进行了总结与展望。     

A Polymer Coating Transfer Enrichment Method for Direct Mass Spectrometry Analysis of Lipids in Biofluid Samples

A porous polymer coating transfer enrichment method is developed for the direct mass spectrometry (MS) analysis of lipids. The enrichment is fast (ca. 1 min) and enables the profiling and quantitation of lipids in small‐volume biofluid samples. Coupled with a photochemical Paternò–Büchi reaction, this method enables the fast determination of lipid structure at the C=C location level and point‐of‐care lipid biomarker analysis.     

An insight into the influence of crystallite size on the performances of microsized spherical Li(Ni<Subscript>0.5</Subscript>Co<Subscript>0.2</Subscript>Mn<Subscript>0.3</Subscript>)O<Subscript>2</Subscript> cathode material composed of aggregated nanosized particles

Relationships between the performance and the crystallite size of the microsized spherical Li(Ni_0.5Co_0.2Mn_0.3)O₂ cathode material composed of aggregated nanosized primary particles have been comprehensively studied. The cathode material was synthesized by a high-temperature solid-state method. The results obtained by XRD, Rietveld refinement, SEM, HR-TEM, DSC, and galvanostatic test show that the crystallite size (XS) of Li(Ni_0.5Co_0.2Mn_0.3)O₂ is greatly affected by the temperature in the range of 750 to 820 °C. Most of all, the crystallite size plays a unique role in the performance of the material. That is, the electrochemical characteristics of Li(Ni_0.5Co_0.2Mn_0.3)O₂, such as discharge capacity, rate performance, and thermal stability, are closely related to the crystallite size. Furthermore, the retention of discharge capacity is determined by that of crystallite size in Li(Ni_0.5Co_0.2Mn_0.3)O₂ after 100 cycles.