Zilin Chen

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (112)312.57 Total impact

  • Lili Wang · Feiyue Yu · Fang Wang · Zilin Chen
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    ABSTRACT: We describe a method for detecting DNA methylation. It is based on direct oxidation of DNA bases at a glassy carbon electrode (GCE) modified with film of a multiwalled carbon nanotube-β-cyclodextrin composite. This nano-structured film causes a strong enhancement on the oxidation current of DNA bases due to its large effective surface area and extraordinary electronic properties. Well-defined peaks were obtained as a result of electro-oxidation of guanine (at 0.67 V), adenine (at 0.92 V), thymine (at 1.11 V), cytosine (at 1.26 V), and 5-methylcytosine (at 1.13 V; all data vs. saturated calomel electrode (SCE)). The potential difference between 5-methylcytosine and cytosine (130 mV) is large enough to enable reliable simultaneous determination and analysis. The interference by thymine can be eliminated by following the principle of complementary pairing between purine and pyrimidine bases in DNA. The modified electrode was successfully applied to the evaluation of 5-methylcytosine in a fish sperm DNA, the methylation level of cytosine was found to be 7.47 %, and the analysis process took less than 1 h.
    No preview · Article · Jan 2016 · Journal of Solid State Electrochemistry
  • Source
    Jing Han · Jue Zhang · Haiyan Zhao · Yan Li · Zilin Chen
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    ABSTRACT: A simple and sensitive high performance liquid chromatographic methodology with fluorescence detection (HPLC-FD) has been developed for simultaneous quantification of doxorubicin (DOX) and its dipeptide conjugate prodrug (PDOX) in mice plasma. The chromatographic separation was carried out on an Amethyst C18 column with gradient mobile phase of 0.1% formic acid and 0.1% formic acid in acetonitrile at a flow rate of 1.0mL/min. The excitation and emission wavelengths were set at 490 and 550nm, respectively. The method was comprehensively validated. The limits of detection were low up to 5.0ng/mL for DOX and 25.0ng/mL for PDOX. And the limits of quantification were low up to 12.5ng/mL for DOX and 50ng/mL for PDOX, which were lower than those for most of the current methods. The calibration curves showed good linearity (R2>0.999) over the concentration ranges. The extraction recoveries ranged from 84.0% to 88.2% for DOX and from 85.4% to 89.2% for PDOX Satisfactory intra-day and inter-day precisions were achieved with RSDs less than 9.1%. The results show that the developed HPLC-FD method is accurate, reliable and will be helpful for preclinical pharmacokinetic study of DOX and PDOX.
    Preview · Article · Dec 2015 · Journal of Pharmaceutical Analysis
  • Xu Ling · Wenpeng Zhang · Zilin Chen
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    ABSTRACT: The authors show that carbon fiber bundles electrochemically modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is a viable sorbent for online solid-phase microextraction (SPME) of the sulfonamides (sulfadiazine, sulfadimidine and sulfamethoxazole) prior to their determination by HPLC. The fibers were packed in a tube loop made from polyether ether ketone (PEEK) that was coupled to the HPLC system for online SPME. Preconcentration factors can reach values of up to 300, and the limit of detection (at an S/N ration of 3) can be as low as 0.05 ng⋅mL−1. The method was applied to the analysis of the sulfonamides in spiked rat plasma with intra-day and inter-day RSDs of <3.33 and <4.57 %, and with recoveries in the range from 91.7 to 97.8 % in spiked plasma. The in-tube SPME was also applied to the determination of the 3 sulfonamides in rat plasma after oral administration (tablet powder) with high sensitivity. In addition to its efficient extraction, the PEEK tube based SPME has chemical and mechanical stability under even harsh conditions. Graphical Abstract Electrochemically modified carbon fibers were packed into polyether ether ketone (PEEK) tube and connect with HPLC system. Good stability and extraction efficiency over 300 fold have been obtained. Application in plasma samples exhibits high extraction efficiency, good reproducibility and recoveries.
    No preview · Article · Dec 2015 · Microchimica Acta
  • Xiao Liu · Wengpeng Zhang · Zilin Chen
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    ABSTRACT: The selective extraction of baicalin is important to its quality control especially when the matrices are complicated. In this work, a novel molecularly imprinted polymer was prepared for the selective extraction of baicalin in herbs. The molecularly imprinted polymer was synthesized by the co-polymerization of 4-vinyl pyridine and ethylene glycol dimethacrylate in the presence of baicalin by a precipitation polymerization method. After the optimization of parameters for molecularly imprinted polymer preparation, including the functional monomer, porogen, sampling solvent and washing solvent, good selectivity was obtained, with an imprinting factor of about 4, which is much better than that achieved by the bulk polymerization method. The performances of the prepared molecularly imprinted polymers were systematically investigated, including adsorption kinetics, isotherm experiment and Scatchard analysis. On the basis of the good adsorptive capability of the prepared molecularly imprinted polymer, it was also applied for the pretreatment of baicalin in Scutellaria baicalensis Georgi. The result showed that most of the matrices were removed and baicalin was selectively enriched. This article is protected by copyright. All rights reserved.
    No preview · Article · Oct 2015 · Journal of Separation Science
  • Fang Wang · Fangfang Yan · Yuling Long · Lili Wang · Zilin Chen
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    ABSTRACT: The mechanisms of the electrochemical oxidation of orientin and its interaction with deoxyribonucleic acid have been investigated using glassy carbon electrode. The electrochemical response of orientin is due to oxidation of phenolic hydroxyl groups on orientin. The whole process is controlled by the adsorption step and concerned 4 electrons and 4 protons. Negative shift of potential and decrease of peak current for electrochemical oxidation of orientin can be observed at bare glassy carbon electrode and deoxyribonucleic acid modified electrode in 0.05 M Na2HPO4-KH2PO4 (pH 7.48), confirming the dominant electrostatic interaction between orientin and deoxyribonucleic acid. Moreover, a reliable and sensitive method of reversed-phase high-performance liquid chromatography-electrochemical detection has been developed for simultaneous determination of the isomer pair orientin/isoorientin. Chromatographic separation was carried out on a reversed-phase C18 column and a mobile phase comprised of acetonitrile and acetate (0.5%, pH 2.97) by amperometric detection with a glassy carbon electrode at the working potential of +1.00 V. The method was validated for linearity, accuracy, precision, and limit of detection. Under the optimized conditions, linear regression analysis for the calibration curve showed a good linear relationship between peak area and their concentrations in the linear range of 89.2 nM to 59.5 μM for orientin with detection limit of 14.9 nM and 78.0 nM to 52.0 μM for isoorientin with a detection limit of 13.0 nM, respectively. Compared to the method using ultraviolet detection, the detection limits are greatly lowered. Finally, the proposed method has been successfully applied to the determination of orientin and isoorientin in Lophatherum gracile Brongn.
    No preview · Article · Oct 2015 · Electrochimica Acta
  • Wenpeng Zhang · Yilin Li · Zilin Chen
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    ABSTRACT: 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, ethyleneglyol dimethacrylate 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 (R(2) ≥ 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. This article is protected by copyright. All rights reserved.
    No preview · Article · Sep 2015 · Journal of Separation Science
  • Fang Wang · Wencheng Gong · Lili Wang · Zilin Chen
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    ABSTRACT: Selective recognition of D-tryptophan (D-Trp) in the presence of Cu(II) was investigated at poly-L-lysine (p-L-Lys) film using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). p-L-Lys film has been immobilized on a glassy carbon electrode (GCE) by cyclic voltammetry (CV) between 0.0 and 1.9 V in 20 mM phosphate buffer solution (pH 8.6). After the p-L-Lys/GCE electrode was incubated with D-Trp solution containing Cu(II) ions, obvious enhancement of electron transfer resistance and decrease of voltammetric current could be observed. If D-Trp was replaced by L-Trp, there was no apparent resistance and current changes. Moreover, no resistance and current changes could be found in the absence of Cu(II). It may be due to the formation of Cu complex with L-lysine and D-tryptophan. Finally, this method was successfully applied to monitoring enantiomeric composition of the D-Trp and L-Trp mixtures.
    No preview · Article · Sep 2015 · Analytical Biochemistry
  • Yue Wu · Wenpeng Zhang · Ying Chen · Zilin Chen
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    ABSTRACT: In this work, a novel molecularly imprinted polymer (MIP) monolithic column with integrated in-column electroosmotic pump (EOP) was designed and successfully prepared to facilitate the capillary chromatography with MIP column. A silica-based EOP was synthesized at the detection end of the MIP monolithic capillary column by so-gel to provide the hydrodynamic driven force for the capillary chromatography. Because of large surface area and low fluidic resistance of the silica monolith, a strong and steady EOF was generated by silica based EOP, indicating that the EOP was quite compatible with MIP capillary column. With the sufficient EOF provided by EOP, the electro-driven based capillary chromatographic separation of nitrophenol isomers was achieved in 4-vinylpyridine (4-VP)-based MIP monolithic capillary, which was originally proved infeasible because of the EOF shortage. No significant influence upon the specific recognition of the MIP was found due to the setting of EOP after the detection window of the column. The influence of experimental parameters on the EOF such as voltage and pH value of running buffer was investigated. The column was also evaluated by capillary liquid chromatographic (cLC) mode to compare with EOP-driven capillary chromatography. Higher column efficiency was obtained by by EOP-driven separation with improved peak shape. The results suggested that EOP-supported technique would be a good way to solve the problem of weak EOF generation in electro-driven capillary chromatography. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · Aug 2015 · Electrophoresis
  • Zhi-Ke He · Chen Liu · Guobin Mao · Chen Su · Xinghu Ji · Zilin Chen
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    ABSTRACT: As the advantages of the excellent optical properties and biocompatibility, DNA-functionalized quantum dots (QDs) have been widely applied in biosensing and bioimaging. Systemin, is an important class of plant peptide hormone firstly identified in plant. In this paper, we have synthesized aptamer-functionalized Zn2+ doped CdTe QDs through a facile one-pot hydrothermal route, and a fluorescent aptasensor based on graphene oxide (GO) is developed for the detection of tomato systemin (TomSys) with the recognition properties of aptamer. In the absence of TomSys, aptamer-functionalized QDs are adsorbed on the surface of GO and the fluorescence is efficiently quenched. While in the presence of TomSys, the specific binding of TomSys with its aptamer competitively releases aptamer-functionalized QDs from the GO surface, leading to the recovery of QDs fluorescence. The results demonstrate that the simple, rapid and cost-efficient biosensor possesses satisfactory sensitivity and selectivity for the detection of TomSys.
    No preview · Article · Jul 2015 · Analytical methods
  • Peng Jiang · Rpmg Wang · Zilin Chen
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    ABSTRACT: The Ag2S quantum dots (QDs) is a promising candidate for biomedical imaging, labeling and sensing. However, coating a ZnS shell on the Ag2S QDs to improve the quantum yields (QYs) is still a challenge. Here, we developed a novel non-injection approach for synthesizing Ag2S and Ag2S/ZnS core/shell QDs using alkanethiols as both ligand and sulfur source. The QY was significantly increased after coating a ZnS shell on the Ag2S core. Moreover, the possible pathway of the sulfur released from the alkanethiol and transferred to Ag2S QDs, which is beneficial for understanding the formation mechanism of thiol-based non-injection synthesis of metal sulfide nanocrystal (NCs), was investigated.
    No preview · Article · Jun 2015 · RSC Advances
  • Zixin Zhang · Wenpeng Zhang · Tao Bao · Zilin Chen
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    ABSTRACT: Stainless steel wire (SSW) is a good substrate for stir bar sorptive extraction (SBSE). However, it is still a challenge to immobilize commonly used cross-linked polymers onto SSW. In this work, we present a new approach for immobilization of the cross-linked organic polymer onto SSW for jacket-free SBSE. A dopamine derivative was firstly synthesized; by introducing a mussel-inspired polydopamine process, a stable coating layer was finally generated on the surface of SSW. Secondly, the cross-linked polymer was synthesized on the polydopamine-modified SSW by using acetonitrile as the porogen, acrylamide (AA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2'-azobis (2-methylpropionitrile) as the initiator. A diluted pre-polymerization solution was carefully prepared to generate a thin layer of the polymer. The prepared poly(EGDMA-AA)-modified stir bar showed high stability and good tolerance toward stirring, ultrasonication, organic solvents, and strong acidic and basic conditions. Morphology and structure characterization of coatings were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The prepared poly(EGDMA-AA)-modified stir bar showed great extraction efficiency toward protoberberines, with enrichment factors of 19-42. An SBSE-HPLC method was also developed for quantitative analysis of protoberberines. The method showed low limits of detection (0.06-0.15ngmL(-1)), wide linear range (0.5-400ngmL(-1)), good linearity (R≥0.9980) and good reproducibility (RSD≤3.60% for intra-day, RSD≤4.73% for inter-day). The developed method has been successfully applied to determine protoberberines in herb and rat plasma samples, with recoveries of 88.53-114.61%. Copyright © 2015 Elsevier B.V. All rights reserved.
    No preview · Article · Jun 2015 · Journal of Chromatography A
  • Fang Wang · Wencheng Gong · Lili Wang · Zilin Chen
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    ABSTRACT: Reduced graphene oxide (RGO) was used to construct a bienzyme biosensor containing horseradish peroxidase (HRP) and glucose oxidase (GOx). A poly(toluidine blue) (pTB) film containing RGO acted as both enzyme immobilization matrix and electron transfer mediator. The bienzyme biosensor was characterized by electrochemical techniques and displays a highly sensitive amperometric response to glucose and hydrogen peroxide (H2O2) at a potential as low as −0.1 V (vs. SCE). It is shown that use of RGO causes a strong enhancement on the amperometric responses. H2O2 formed by the action of GOx in the presence of oxygen can be further reduced by HRP in the pTB film contacting the RGO modified electrode. In the absence of oxygen, glucose oxidation proceeds by another mechanism in which electron transfer occurs from GOx to the electrode and with pTB acting as the mediator. Amperometric responses to glucose and H2O2 follow Michaelis-Menten kinetics. The experimental conditions were optimized, and under these conditions glucose can be determined in the 80 μM to 3.0 mM range with a detection limit of 50 μM. H2O2, in turn, can be quantified in up to 30.0 μM concentration with a detection limit of 0.2 μM. The bienzyme biosensor is reproducible, repeatable and stable. Finally, it has been successfully applied to the determination of glucose in plasma samples. Graphical Abstract Schematic representation of glocuse detection at GCE/RGO/pTB-HRP-GOx.
    No preview · Article · Jun 2015 · Microchimica Acta
  • Lilin Tang · Wenpeng Zhang · Haiyan Zhao · Zilin Chen
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    ABSTRACT: A capillary electrophoresis-based method for the screening of tyrosinase inhibitors in traditional Chinese medicines was developed. The method integrated electrophoretically mediated microanalysis with sandwich-mode injection, partial filling and rapid polarity switching techniques, and carried out on-column enzyme reaction and the separation of substrate and product. The conditions were optimized including the background electrolyte, mixing voltage and the incubation time. Finally, screening of nine standard natural compounds of traditional Chinese medicines was carried out. The inhibitors can be directly identified from the reduced peak area of the product compared to that obtained without any inhibitor. Chlorogenic acid (100 μM) showed inhibitory activity with the inhibitory percentage of 19.8%, while the other compounds showed no inhibitory activity. This method has great application potential in drug discovery from traditional Chinese medicines. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · May 2015 · Journal of Separation Science
  • Jiawei Meng · Wenpeng Zhang · Tao Bao · Zilin Chen
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    ABSTRACT: In this work, a novel magnetic nanomaterial functionalized with a molecularly imprinted polymer was prepared for extraction of protoberberine alkaloids. Molecularly imprinted polymers were made on the surface of Fe3 O4 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. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · Apr 2015 · Journal of Separation Science
  • Juan Zhang · Wenpeng Zhang · Tao Bao · Zilin Chen
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    ABSTRACT: Zeolitic imidazolate frameworks (ZIFs), a subfamily of metal-organic frameworks (MOFs), have received considerable attention as a novel porous material for sample preparation due to their fascinating structures and unique properties. Here, we developed a novel bio-inspired polydopamine (PDA) method to immobilize ZIFs inside the chemical resistance poly(ether ether ketone) (PEEK) tube for online solid-phase microextraction (SPME). Firstly, PDA layer was assembled inside the PEEK tube. Secondly, attributing to its noncovalent adsorption and covalent reaction ability, PDA could attract and anchor ZIF-8 nutrients onto the inner surface of PEEK tube to promote the nucleation and growth of ZIF-8. The morphology and surface properties of the prepared ZIF-8-PDA-PEEK tube were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. The ZIF-8-PDA-PEEK tube exhibits excellent extraction efficiency toward six polycyclic aromatic hydrocarbons (PAHs), with enrichment factor from 550 to 734. The developed online SPME-HPLC method shows good linearity (10-5000pg/mL) and low detection limits (0.5-5pg/mL) for six PAHs. It also has been used to determine PAHs in environmental samples, with recoveries in the range of 82.5-98.6%. Copyright © 2015 Elsevier B.V. All rights reserved.
    No preview · Article · Feb 2015 · Journal of Chromatography A
  • Tao Bao · Juan Zhang · Wenpeng Zhang · Zilin Chen
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    ABSTRACT: Much attention is being paid to applying metal-organic frameworks (MOFs) as stationary phases in chromatography because of their fascinating properties, such as large surface-to-volume ratios, high levels of porosity, and selective adsorption. HKUST-1 is one of the best-studied face-centered-cubic MOF containing nano-sized channels and side pockets for film growth. However, growth of HKUST-1 framework inside capillary column as stationary phase for capillary electrochromatography is a challenge work. In this work, we carry out the growth of HKUST-1 on the inner wall of capillary by using liquid-phase epitaxy process at room temperature. The fabricated HKUST-1@capillary can be successfully used for the separation of substituted benzene including methylbenzene, ethylbenzene, styrene, chlorobenzene, bromobenzene, o-dichlorobenzene, benzene series, phenolic acids, and benzoic acids derivates. High column efficiency of 1.5×10(5)N/m for methylbenzene was achieved. The formation of HKUST-1 grown in the capillary was confirmed and characterized by scanning electron microscopy images, Fourier transform infrared spectra and X-ray diffraction. The column showed long lifetime and excellent stability. The relative standard deviations for intra-day and inter-day repeatability of the HKUST-1@capillary were lower than 7%. Copyright © 2015 Elsevier B.V. All rights reserved.
    No preview · Article · Jan 2015 · Journal of Chromatography A
  • Wen Ma · Peng Gao · Jun Fan · Yuki Hashi · Zilin Chen
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    ABSTRACT: A gas chromatographic–mass spectrometric method with monolithic material sorptive extraction (MMSE) pretreatment was developed to determine the breath gas composition in lung cancer patients. MonoTrap silica monolithic and hybrid adsorbent was selected as the extraction medium during MMSE, given its strong capacity to extract volatile organic compounds (VOC) from exhaled gas. Under the appropriate conditions, high extraction efficiency was achieved. Using the selected ion-monitoring mode, the limit of detection (signal-to-noise ratio 3) for the benzene series was 0.012–2.172 ng L−1. The limit of quantitation (signal-to-noise ratio, 10) was 0.042–7.24 ng L−1. The linearity range of the method was 4–400 ng L−1. Average recovery of the benzene series at lower concentrations was 65–74% (20 ng L−1). The relative standard deviation of benzene series contents determined within the linear range of detection was <10% of the mean level determined. Our proposed method is simple, rapid and sensitive, and can be competently applied to determine the breath gas composition of lung cancer patients. Copyright © 2014 John Wiley & Sons, Ltd.
    No preview · Article · Nov 2014 · Biomedical Chromatography
  • Wenpeng Zhang · Wei Zhou · Zilin Chen
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    ABSTRACT: Determination of bioactive compounds in traditional Chinese medicines and biological samples is usually interfered by co-existing components in matrices. In this work, we prepared novel multilayer functional graphene/polydopamine-modified polytetrafluoroethylene microtube for selective solid-phase microextraction of three bioactive compounds in Fructus Psoraleae. Functional graphene/polydopamine-modified polytetrafluoroethylene microtube showed good extraction efficiency towards bavachin, isobavachalcone and bavachinin; enrichment from 357- to 737-fold was obtained for these compounds. For qualitative analysis, an online solid-phase microextraction with high-performance liquid chromatography method was developed, which showed low limits of detection of 0.02 ng/mL by using UV detection, which is significantly more sensitive than previously reported methods. The proposed method has been used to determine bavachin, isobavachalcone and bavachinin in Fructus Psoraleae, the contents of three compounds were quantified to be 64.0, 324.0 and 384.5 (μg/g); recoveries were 93.4–101.1%. The proposed method has also been applied to determine bavachin, isobavachalcone and bavachinin in rat plasma samples after oral administration of Fructus Psoraleae.This article is protected by copyright. All rights reserved
    No preview · Article · Nov 2014 · Journal of Separation Science
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    ABSTRACT: In this work, we interestingly happened to observe the adsorption of stainless steel sample loop of HPLC. The adsorptive behaviors of the stainless steel loop toward different kinds of compounds were studied, including polycyclic aromatic hydrocarbons (PAHs), halogeno benzenes, aniline derivatives, benzoic acid derivatives, phenols, benzoic acid ethyl ester, benzaldehyde, 1-phenyl-ethanone and phenethyl alcohol. The adsorptive mechanism was probably related to hydrophobic interaction, electron-rich element-metal interaction and hydrogen bond. Universal adsorption of stainless steels was also testified. Inspired by its strong adsorptive capability, bare stainless steel loop was developed as a modification-free in-tube device for solid-phase microextraction (SPME), which served as both the substrate and sorbent and possessed ultra-high strength and stability. Great extraction efficiency toward PAHs was obtained by stainless steel loop without any modification, with enrichment factors of 651-834. By connecting the stainless steel loop onto a six-port valve, an online SPME-HPLC system was set up and an SPME-HPLC method has been validated for determination of PAHs. The method has exceptionally low limits of detection of 0.2-2pg/mL, which is significantly lower than that of reported methods with different kinds of sorbents. Wide linear range (0.5-500 and 2-1000pg/mL), good linearity (R(2)≥0.9987) and good reproducibility (RSD≤2.9%) were also obtained. The proposed method has been applied to determine PAHs in environmental samples. Good recoveries were obtained, ranging from 88.5% to 93.8%.
    No preview · Article · Sep 2014 · Journal of Chromatography A
  • Qiuyue Xiang · Ying Chen · Zilin Chen
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    ABSTRACT: In this study, a simple, sensitive and rapid reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for the simultaneous determination of lycorine, lycoramine and galantamine in the traditional Chinese medicine Lycoris radiate with fluorescence detection (FD). The chromatographic separation of three compounds was performed on an Intertsil ODS-SP column. The mobile phase consisted of a mixture of potassium dihydrogen phosphate (KH2PO4) solution (15 mM, pH 6.35) - methanol (50:50, v/v) delivered at flow rate of 0.8 mL min-1. The excitation wavelength and emission wavelength for detection were set at 285 and 320 nm, respectively. Under the optimal conditions, the baseline separation of these three alkaloids can be carried out within 12 min. The developed method was validated by limit of detection, limit of quantification, linearity, intra-day precision, inter-day precision and recovery test. Finally, the developed HPLC-FD method was successfully applied to the simultaneous determination of lycorine, lycoramine and galantamine in the extract of herb Lycoris radiata from different provinces and rat plasma samples after oral administration of Lycoris radiata extract.
    No preview · Article · Sep 2014 · Analytical methods

Publication Stats

2k Citations
312.57 Total Impact Points

Institutions

  • 2015
    • Chinese Academy of Sciences
      Peping, Beijing, China
  • 2007-2015
    • Wuhan University
      • • School of Pharmaceutical Sciences
      • • Department of Pharmaceutical Analysis and Screening
      Wu-han-shih, Hubei, China
  • 2005-2006
    • University of Notre Dame
      • Department of Chemical and Biomolecular Engineering
      South Bend, Indiana, United States
  • 1998-2004
    • Tokyo Metropolitan University
      • Department of Applied Chemistry
      Edo, Tōkyō, Japan