Yan Li

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Name: 李嫣; Yan Li

Organization: Fudan University

Department: Department of Pharmaceutical Analysis

Title: Associate Professor

TOPICS

Inorganic Chemistry

Metal Organic Frameworks Mesoporous Material

Chemicals
References

One-step synthesis of carboxyl-functionalized metal-organic framework with binary ligands for highly selective enrichment of N-linked glycopeptides

Co-reporter:QianJing Liu, Yiqin Xie, Chunhui Deng, Yan Li

Talanta 2017 Volume 175(Volume 175) pp:

Publication Date(Web):1 December 2017

DOI:10.1016/j.talanta.2017.07.067

•One-step synthesis of carboxyl-functionalized metal-organic framework (denoted as UiO-66-COOHs) with binary ligands.•Excellent hydrophilicity, high selectivity and sensitivity for glycopeptide enrichment.•This method offered a new platform of MOFs’ modification for glycopeptide enrichment.Highly efficient and selective enrichment of glycopeptides from complex biosamples is vital prior to mass spectrometry analysis. In this work, a hydrophilic metal organic framework with free carboxylic groups (denoted as UiO-66-COOH) was synthesized in one step with binary ligands. Compared with pure UiO-66 with one ligand, UiO-66-COOH containing binary ligands demonstrated greater hydrophilicity and performed much better in selective enrichment of glycopeptides. The as-prepared material demonstrated excellent performance for selective enrichment of glycopeptides from tryptic digests of standard glycoproteins and practical biological samples.Download high-res image (108KB)Download full-size image

Designed synthesis of ultra-hydrophilic sulfo-functionalized metal-organic frameworks with a magnetic core for highly efficient enrichment of the N-linked glycopeptides

Co-reporter:Yiqin Xie, Chunhui Deng, Yan Li

Journal of Chromatography A 2017 Volume 1508(Volume 1508) pp:

Publication Date(Web):28 July 2017

DOI:10.1016/j.chroma.2017.05.055

•A facile route for preparation of an ultra-hydrophilic sulfo-functionalized metal-organic framework.•Excellent hydrophilicity with the contact angle data supported.•Strong magnetic responsiveness, high selectivity and sensitivity for glycopeptide enrichment in standard proteins and biological samples.•Stable and reusable for several times.Highly efficient extraction and enrichment of the N-linked glycopeptides from complex biological samples before mass spectrometry analysis remains important but challenging, due to the low abundance and suppression by proteins and salts. Herein, a facile route to an ultra-hydrophilic metal-organic frameworks (MOFs)-functionalized magnetic nanoparticle (Fe3O4@PDA@Zr-SO3H) was proposed. The as-prepared MOFs was endowed with excellent and unique properties, such as excellent hydrophilicity, ultrahigh surface area, and strong magnetic responsiveness. By virtue of these properties and based on hydrophilic interaction, Fe3O4@PDA@Zr-SO3H exhibited outstanding sensitivity and selectivity, remarkable recyclability and stability towards N-linked glycopeptide enrichment. In deep, a total of 177 N-linked glycopeptides, assigned to 85 different glycoproteins, were identified from the healthy human serum after treated with the Fe3O4@PDA@Zr-SO3H. These results confirmed that our strategy offered a promising platform for preparing hydrophilic metal-organic framework-functionalized magnetic nanoparticles for glycosylation analysis by mass spectrometry analysis.

Restricted access magnetic core-mesoporous shell microspheres with C8-modified interior pore walls for the identification of 20(S)-protopanaxadiol metabolites in rat plasma using UPLC-Q-TOF-MS/MS

Co-reporter:Jin Ling, Yingjia Yu, Jianan Feng, Changjiang Xu, Jiebing Jiang, Liping Wang, Jiakun Long, Yan Li, Gengli Duan

Journal of Chromatography B 2017 Volume 1054(Volume 1054) pp:

Publication Date(Web):1 June 2017

DOI:10.1016/j.jchromb.2017.04.004

In the present study, a novel sample preparation method based on magnetic core-mesoporous shell microspheres with C8-modified interior pore walls (C8-Fe3O4@mSiO2) was established for the identification of 20(S)-protopanaxadiol (PPD) metabolites in rat plasma by UPLC-Q-TOF-MS/MS analysis. C8-Fe3O4@mSiO2 allowed selective extraction of PPD metabolites from rat plasma by excluding macromolecules in the plasma owing to size exclusion effect. Five extraction conditions including the amount of C8-Fe3O4@mSiO2 microspheres used, extraction time, elution solvents, elution volume, and elution time were investigated and optimized. The present method was compared with two conventional sample preparation methods: protein precipitation and C8 solid phase extraction (C8-SPE). Our method provided higher UPLC intensity of result than protein precipitation method. While the resulting intensity of our method and that of C8-SPE were not significantly different, it consumed less processing time (15 min 55 s for C8-Fe3O4@mSiO2, and 27 min 30 s for C8-SPE). Finally, the proposed method was successfully applied in the identification of PPD metabolites in vivo, in which a total of 17 metabolites and the parent drug were identified in rat plasma.

Microwave-assisted enzymatic hydrolysis followed by extraction with restricted access nanocomposites for rapid analysis of glucocorticoids residues in liver tissue

Co-reporter:Jianan Feng, Xiaodan Liu, Yan Li, Gengli Duan

Talanta 2016 Volume 159() pp:155-162

Publication Date(Web):1 October 2016

DOI:10.1016/j.talanta.2016.06.013

•Microwave-assisted enzymatic hydrolysis and RAM-SPE were combined.•C8-functionalized hydrophobic interior pore-walls for extraction of glucocorticoids.•Different enzymatic hydrolysis influencing factors were optimized.•Different extraction conditions were optimized.We developed a novel, simple and fast method for the determination of glucocorticoids residues in liver tissue by combining microwave-assisted enzymatic hydrolysis and restricted access matrix dispersive solid phase extraction (RAM-dSPE) followed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Firstly, microwave-assisted enzymatic hydrolysis was introduced in order to obtain a maximum amount of unconjugated parent drug in a short time (8 s), while the traditional method commonly needs 4–12 h. Secondly, further cleanup was carried out by RAM-dSPE based on the graphene@mSiO2-C8 nanomaterials which were synthesized by coating mesoporous silica onto hydrophilic graphene nano-sheets through a surfactant-mediated co-condensation sol-gel process. The enzymatic hydrolysis influencing factors (pH of the buffer, microwave radiation power, incubation time) and the experimental conditions of RAM-dSPE (sorbents amount, type and volume of the elution solvent, adsorption and desorption time) were optimized. Three glucocorticoids (prednisolone (PREL), betamethasone (BE) and dexamethasone (DE)) were selected as models to evaluate the feasibility of the method. According to the results, the developed method provided low detection limit (S/N=3) of 0.01–0.05 μg kg−1 and good linearity range of 0.25–800 μg kg−1 (R2>0.996) for glucocorticoids. The limit of quantification (S/N=10) range from 0.03 to 0.19 μg kg−1. Compared with other traditional methods, the developed method could provide similar or even better results in a greatly reduced analysis time.

Three-layer structure graphene/mesoporous silica composites incorporated with C8-modified interior pore-walls for residue analysis of glucocorticoids in milk by liquid chromatography–tandem mass spectrometry

Co-reporter:Xiaodan Liu, Jianan Feng, Xueni Sun, Yan Li, Gengli Duan

Analytica Chimica Acta 2015 Volume 884() pp:61-69

Publication Date(Web):16 July 2015

DOI:10.1016/j.aca.2015.05.020

•An enrichment (glucocorticoids) technique based on graphene@mSiO2-C8 was developed.•The mesopores on the surface of the microspheres exclude proteins from the matrix.•Different extraction variables optimized.•C8-functionalized graphene@mSiO2 composite nanosheets for extraction of glucocorticoids.Three-layer structure graphene/mesoporous silica composites incorporated with C8-modified interior pore-walls (graphene@mSiO2-C8) were prepared and applied for efficient extraction of glucocorticoid residuals in milk followed by liquid chromatography-tandem mass spectrometry (LC–MS/MS) analysis. The graphene@mSiO2-C8 nanocomposites were synthesized by coating C8-modified mesoporous silica onto hydrophilic graphene nanosheets through a simple surfactant-mediated co-condensation sol–gel process. The obtained nanosheets possess unique properties of large surface area (632 m2/g), extended plate-like morphology in the exterior surface, highly open pore structure with uniform pore size (2.8 nm), numerous C8-modified interior pore-walls, as well as good water dispersibility. The performance of the prepared graphene@mSiO2-C8 materials for extracting small hydrophobic molecules directly from complex protein-rich samples was evaluated by analysis of glucocorticoids in milk. Extraction conditions such as sorbents amount, type and volume of eluting solvent, time of adsorption and desorption were investigated and optimized to achieve the best efficiency. Method validations including linearity, recovery, repeatability, and limit of detection (LOD) were also studied. The results indicated that this methodology provided low LOD (S/N = 3, 0.0075–0.03 ng mL−1) and good linearity (0.03–60 ng mL−1, R2 > 0.996) for glucocorticoids. Satisfactory reusability and stability were also obtained during the extraction. Finally, the graphene@mSiO2-C8 composites were successfully applied to the extraction and residue analysis of glucocorticoids in real milk samples. The experimental results showed that this novel approach offered an attractive choice for convenient, efficient and rapid solid-phase extraction of targeted hydrophobic compounds in biological samples.

Magnetic Binary Metal Oxides Affinity Probe for Highly Selective Enrichment of Phosphopeptides

Co-reporter:Mengyi Wang, Chunhui Deng, Yan Li, and Xiangmin Zhang

ACS Applied Materials & Interfaces 2014 Volume 6(Issue 14) pp:11775

Publication Date(Web):June 9, 2014

DOI:10.1021/am502530c

In this work, for the first time, binary metal oxides ((Ti–Sn)O4) were integrated into one entity on an atomic scale on magnetic graphene as affinity probe for highly selective enrichment of phosphopeptides. The newly prepared Fe3O4/graphene/(Ti–Sn)O4 (magG/(Ti–Sn)O4) composites gathered the advantages of large specific surface area of graphene, superparamagnetism, and biocompatibility of iron oxide, and enhanced affinity properties of binary metal oxides. The phosphopeptide enrichment efficiency of the magG/(Ti–Sn)O4 composite was investigated, and the results indicated an ultralow detection limit (1 pg/μL or 4.0 × 10–11 M) and an ultrahigh selectivity (weight ratio of β-casein and BSA reached up to 1:1500). Compared with magnetic affinity probes with single metal oxide (magG/TiO2, magG/SnO2) or the simple physical mixture of magG/TiO2 and magG/SnO2, the magG/(Ti–Sn)O4 composite possessed stronger specificity, higher selectivity and better efficiency; and more importantly, it possessed the ability to enrich both the mono- and multi- phosophorylated peptides, demonstrating the notable features of the novel binary metal oxides affinity probe in the specific and selective enrichment of phosphopeptides. Additionally, by utilizing the magG/(Ti–Sn)O4 composites, a total number of 349 phosphorylation sites on 170 phosphopeptides including 66 monophosphopeptides and 104 multiphosphopeptides were captured and identified from mouse brain, indicating the great potential for their application in phosphoproteomics analysis in the future.Keywords: binary metal oxide affinity chromatography; BMOAC; enrichment; graphene; magnetic; phosphopeptide

Size-Exclusive Magnetic Graphene/Mesoporous Silica Composites with Titanium(IV)-Immobilized Pore Walls for Selective Enrichment of Endogenous Phosphorylated Peptides

Co-reporter:Nianrong Sun, Chunhui Deng, Yan Li, and Xiangmin Zhang

ACS Applied Materials & Interfaces 2014 Volume 6(Issue 14) pp:11799

Publication Date(Web):July 1, 2014

DOI:10.1021/am502529a

Developing an effective separation method is necessary for identifying low-abundant endogenous phosphorylated peptides with the removal of proteins. In this work, we prepared size-exclusive magnetic graphene/mesoporous silica composites with titanium(IV)-immobilized pore walls (denoted as Ti4+-MGMSs) for capturing endogenous phosphorylated peptides for mass spectrometry analysis. The introduction of hydrophilic polydopamine simplified the synthetic process of Ti4+-MGMSs, and the ordered mesoporous channels are beneficial to the trapping of endogenous phosphopeptides while large-size proteins are excluded. Furthermore, the magnetic performance greatly simplifies the entire process of enrichment. With all of the advances, the novel Ti4+-MGMSs present high enrichment efficiency either from the low concentration of β-casein tryptic digest (0.5 fmol/μL) or the mixture of β-casein tryptic digest and α-casein (or plus bovine serum albumin, with a mass ratio up to 1:500). Besides, Ti4+-MGMSs have also been successfully applied to enrich endogenous phosphorylated peptides from human serum and human saliva.Keywords: endogenous phosphorylated peptides; magnetic graphene; mesoporous silica; size-exclusive; titanium

Highly Selective Enrichment of N-Linked Glycan by Carbon-Functionalized Ordered Graphene/Mesoporous Silica Composites

Co-reporter:Nianrong Sun, Chunhui Deng, Yan Li, and Xiangmin Zhang

Analytical Chemistry 2014 Volume 86(Issue 4) pp:2246

Publication Date(Web):January 24, 2014

DOI:10.1021/ac404103r

Abnormal protein glycosylation has been demonstrated to be associated with many diseases; therefore, it is very important to conduct a comprehensive structure analysis of glycan for prognosis and diagnosis of diseases, such as cancer. In this work, for the first time, carbon-functionalized ordered graphene/mesoporous silica composites (denoted as C-graphene@mSiO2) with large surface area and uniform pore size were designed and synthesized. By taking advantage of the special interaction between the carbon and glycans as well as size-exclusion ability, 25 N-linked glycans released from ovalbumin were observed clearly with strong MS signals and increased signal-to-noise (S/N) ratio. In addition, after enrichment with the C-graphene@mSiO2 composites, 48 N-linked glycans (S/N > 10) with sufficient peak intensities were obtained from only 400 nL of healthy pristine human serum. The facile and low-cost synthesis method as well as high selective enrichment ability of the novel C-graphene@mSiO2 composite makes it a promising tool for glycosylation research.

Metal Oxide Affinity Chromatography Platform–Polydopamine Coupled Functional Two-Dimensional Titania Graphene Nanohybrid for Phosphoproteome Research

Co-reporter:Yinghua Yan, Xueni Sun, Chunhui Deng, Yan Li, and Xiangmin Zhang

Analytical Chemistry 2014 Volume 86(Issue 9) pp:4327

Publication Date(Web):March 27, 2014

DOI:10.1021/ac500047p

In this work, a facile route was initially developed for preparation of a novel metal oxide affinity chromatography (MOAC) material by grafting titania nanoparticles on polydopamine (PD)-coated graphene (denoted as G@PD@TiO2). In the first step, self-assemble polymerization of dopamine on graphene was performed in basic solution at room temperature, which not only offered the coupling linker between titania and graphene but also improved the hydrophilicity and biological compatibility of the nanohybrids. Thereafter, the titania nanoparticles were grafted on the surface of the PD-coated graphene via a simple hydrothermal treatment. The as-prepared G@PD@TiO2 nanohybrids exhibited high sensitivity (detection limit of 5 fmol) and high selectivity for phosphopeptides at a low molar ratio of phosphopeptides/nonphosphopeptides (1:1000). Moreover, the as-prepared nanohybrids were also investigated for enrichment of phosphopeptides from real biological samples (human serum and mouse brain). A total number of 556 phosphorylation sites were identified from the digest of mouse brain proteins, showing great potential in the practical application.

Fluorocarbon-bonded magnetic mesoporous microspheres for the analysis of perfluorinated compounds in human serum by high-performance liquid chromatography coupled to tandem mass spectrometry

Co-reporter:Xiaodan Liu, Yingjia Yu, Yan Li, Haiying Zhang, Jin Ling, Xueni Sun, Jianan Feng, Gengli Duan

Analytica Chimica Acta 2014 Volume 844() pp:35-43

Publication Date(Web):24 September 2014

DOI:10.1016/j.aca.2014.07.032

•New SPE method was developed for analysis of PFCs in human serum.•Fluorocarbon-bonded magnetic mesoporous microspheres were used as SPE absorbents.•PFCs in serum were directly extracted without any other pretreatment procedure.•The PFCs-adsorbed microspheres were simply and rapidly isolated by using a magnet.We report herein an extraction method for the analysis of perfluorinated compounds in human serum based on magnetic core–mesoporous shell microspheres with decyl-perfluorinated interior pore-walls (Fe3O4@mSiO2-F17). Thanks to the unique properties of the Fe3O4@mSiO2-F17 microspheres, macromolecules like proteins could be easily excluded from the mesoporous channels due to size exclusion effect, and perfluorinated compounds (PFCs) in protein-rich biosamples such as serum could thus be directly extracted with the fluorocarbon modified on the channel wall without any other pretreatment procedure. The PFCs adsorbed Fe3O4@mSiO2-F17 microspheres could then be simply and rapidly isolated by using a magnet, followed by being identified and quantified by LC–MS/MS (high-performance liquid chromatography coupled to tandem mass spectrometry). Five perfluorinatedcarboxylic acids (C6, C8–C11) and perfluorooctane sulfonate (PFOS) were selected as model analytes. In order to achieve the best extraction efficiency, some important factors including the amount of Fe3O4@mSiO2-F17 microspheres added, adsorption time, type of elution solvent, eluting solvent volume and elution time were investigated. The ranges of the LOD were 0.02–0.05 ng mL−1 for the six PFCs. The recovery of the optimized method varies from 83.13% to 92.42% for human serum samples.

Titanium(IV)-Immobilized Hydrophilic Hierarchically Ordered Macro-/Mesoporous Silica for Fast Enrichment of Phosphopeptides

Co-reporter:Dr. Yinghua Yan;Zhifang Zheng; Chunhui Deng; Xiangmin Zhang

ChemPlusChem 2014 Volume 79( Issue 5) pp:662-666

Publication Date(Web):

DOI:10.1002/cplu.201300411

Abstract

Feasible design is essential to achieve ideal chemical and biological properties of nanomaterials. For the first time, new nanocomposites with a polydopamine coating on hierarchically ordered macro-/mesoporous silica functionalized with titanium ions (denoted as HOMMS-PD-Ti⁴⁺) were prepared through a facile reaction route at room temperature. The applicability of as-synthesized HOMMS-PD-Ti⁴⁺ for the selective enrichment of phosphopeptides was tested. The experimental results demonstrate that, by taking advantage of the pure phosphate–Ti⁴⁺ interface and high loading amount of Ti⁴⁺, HOMMS-PD-Ti⁴⁺ presents remarkable selectivity for phosphopeptides, even at a low molar ratio of phosphopeptides/non-phosphopeptides (1:1000) with a very rapid enrichment speed (within 1 min). The superior sensitivity for low-abundant phosphopeptides and the high selectivity and effectiveness for the enrichment of phosphopeptides from human serum are also proven. These outstanding features demonstrate that HOMMS-PD-Ti⁴⁺ exhibits great potential in phosphoproteome research in the future.

Hydrophilic Polydopamine-Coated Graphene for Metal Ion Immobilization as a Novel Immobilized Metal Ion Affinity Chromatography Platform for Phosphoproteome Analysis

Co-reporter:Yinghua Yan, Zhifang Zheng, Chunhui Deng, Yan Li, Xiangmin Zhang, and Pengyuan Yang

Analytical Chemistry 2013 Volume 85(Issue 18) pp:8483

Publication Date(Web):August 13, 2013

DOI:10.1021/ac401668e

To discover trace phosphorylated proteins or peptides with great biological significance for in-depth phosphoproteome analysis, it is urgent to develop a novel technique for highly selective and effective enrichment of phosphopeptides. In this work, an IMAC (immobilized metal ion affinity chromatography) material with polydopamine coated on the surface of graphene and functionalized with titanium ions (denoted as Ti4+-G@PD) was initially designed and synthesized. The newly prepared Ti4+-G@PD with enhanced hydrophilicity and biological compatibility was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and infrared (IR), and its performance for selective and effective enrichment of phosphopeptide was evaluated with both standard peptide mixtures and human serum.

Restricted access magnetic core-mesoporous shell microspheres with C8-modified interior pore-walls for the determination of diazepam in rat plasma by LC-MS

Co-reporter:Xiaodan Liu, Yingjia Yu, Yan Li, Suli Ning, Tingting Liu, Fajie Li, Gengli Duan

Talanta 2013 Volume 106() pp:321-327

Publication Date(Web):15 March 2013

DOI:10.1016/j.talanta.2012.11.015

In this study, a novel enrichment technique based on magnetic core-mesoporous shell microspheres with C8-modified interior pore-walls (C8-Fe3O4@mSiO2) was successfully developed for the determination of diazepam in rat plasma by LC-MS. Due to the unique properties of the synthesized C8-Fe3O4@mSiO2 microspheres (C8-modified magnetic mesoporous microsphere), small drug molecules like diazepam can enter the mesopore channels and be efficiently absorbed through hydrophobic interaction by interior C8-groups (Octyl functional groups). Large molecules like proteins are excluded from the mesopore channels as a result of size exclusion effect, leading to direct extraction of drug molecules from protein-rich biosmaples such as plasma without any other pretreatment procedure. Moreover, diazepam adsorbed C8-Fe3O4@mSiO2 microspheres could be simply and rapidly isolated through placing a magnet on the bottom of container, and then diazepam could be easily eluted from C8-Fe3O4@mSiO2 microspheres for further LC-MS analysis. Extraction conditions such as amounts of C8-Fe3O4@mSiO2 microspheres added, adsorption time, elution solvent and elution time were investigated. Method validations including linear range, the limit of detection, precision, and recovery were also studied. The results indicated that the proposed method based on C8-Fe3O4@mSiO2 microspheres was simple and accurate for the analysis of diazepam in the rat plasma. And it will provide new ideas for analyzing plasma concentration and pharmacokinetics of similar drugs.Highlights► An enrichment technique based on C8-Fe3O4@mSiO2 microspheres was developed. ► Mesopores on the surface of the microspheres exclude proteins from the sample. ► The C8 groups modified on the inner walls extract drug molecules from the sample. ► The strong magnetic behavior of the microspheres ensure a fast and easy separation.

Study on infrared-assisted extraction coupled with high performance liquid chromatography (HPLC) for determination of catechin, epicatechin, and procyanidin B2 in grape seeds

Co-reporter:Yi Cai, Yingjia Yu, Gengli Duan, Yan Li

Food Chemistry 2011 Volume 127(Issue 4) pp:1872-1877

Publication Date(Web):15 August 2011

DOI:10.1016/j.foodchem.2011.02.026

In this study, infrared-assisted extraction (IRAE) was developed and combined with HPLC for the determination of catechin, epicatechin, and procyanidin B2 in grape seeds. Three factors, extraction solvent, solid/liquid ratio, and illumination time, were investigated to optimise the extraction method of catechin, epicatechin, and procyanidin B2 from grape seeds. The chosen infrared-assisted extraction conditions were as follows: a 50% methanol solution as extraction solvent, solid/liquid ratio of 1:150 g/mL and illumination time of 30 min. The extraction efficiency of IRAE was compared with conventional microwave-assisted extraction (MAE), ultrasonic extraction (UE), and classical electrical heating (CEH) methods. An initial HPLC method was established to identify and quantitate catechin, epicatechin, and procyanidin B2 from grape seeds, simultaneously. The HPLC method was validated for parameters including linearity, analytic limit, reproducibility, accuracy and recovery. The results indicted that IRAE has a great potential for offering an alternative technique for extraction of active components from plants.Research highlights► The IRAE was a new extraction method. ► Catechin, epicatechin, procyanidin B2 determined in one chromatographic condition. ► The IRAE indicated its own merit comparing with traditional extraction methods.

High-performance liquid chromatographic determination of memantine hydrochloride in rat plasma using sensitive fluorometric derivatization

Co-reporter:Mei-Fen Xie;Wei Zhou;Xin-Yi Tong;Yi-Le Chen;Yi Cai, ;Geng-Li Duan

Journal of Separation Science 2011 Volume 34( Issue 3) pp:241-246

Publication Date(Web):

DOI:10.1002/jssc.201000579

Abstract

In this study, we investigated a simple, sensitive and reliable liquid chromatography-fluorescence detection method for the determination of memantine hydrochloride in rat plasma which was based on derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). For the first time, FMOC-Cl was introduced into derivatization of memantine hydrochloride in rat plasma. The amino groups of memantine hydrochloride and amantadine hydrochloride (internal standard) were trapped with FMOC-Cl to form memantine hydrochloride-FMOC-Cl and amantadine hydrochloride-FMOC-Cl compositions, which can be very compatible for LC-FLD. Precipitation of plasma proteins by acetonitrile was followed by vortex mixing and centrifugation. Chromatographic separation was performed on a C₁₈ column (DIAMONSIL 150×4.6 mm, id 5 μm) with a mobile phase consisting of acetonitrile and water at a flow rate of 1.0 mL/min. The retention times of memantine hydrochloride-FMOC-Cl and amantadine hydrochloride-FMOC-Cl compositions were 23.69 and 40.27 min, respectively. Optimal conditions for the derivatization of memantine hydrochloride were also described. The limit of quantification (LOQ) was 25 ng/mL for memantine hydrochloride in plasma, the linear range was 0.025–5.0 μg/mL in plasma with a correlation coefficient (r) of 0.9999. The relative standard deviations (RSDs) of intra-day and inter-day assays were 4.46–12.19 and 5.23–11.50%, respectively. The validated method was successfully applied to the determination of memantine hydrochloride in rat plasma samples.

Multiple headspace single-drop microextraction coupled with gas chromatography for direct determination of residual solvents in solid drug product

Co-reporter:Yingjia Yu, Bin Chen, Cidan Shen, Yi Cai, Meifen Xie, Wei Zhou, Yile Chen, Yan Li, Gengli Duan

Journal of Chromatography A 2010 Volume 1217(Issue 32) pp:5158-5164

Publication Date(Web):6 August 2010

DOI:10.1016/j.chroma.2010.06.009

This paper proposed a multiple headspace single-drop microextraction (MHS-SDME) method coupled to gas chromatography with flame-ionization detection (GC-FID) for direct determination of residual solvents in solid drug product. The MHS-SDME technique is based on extrapolation to an exhaustive extraction of consecutive extractions from the same sample which eliminates the matrix effect on the quantitative analysis of solid samples. The total peak area of analyte is calculated with a beta constant which can be obtained from the slope of the linear regression that related to the peak area of each extraction and the number of extraction times. In this work, a model drug powder was chosen and the amounts of residues of two solvents, methanol and ethanol, were investigated. The factors influencing the extraction process including extraction solvent, microdrop volume, extraction time, sample amount, thermostatting temperature and incubation time were studied. 10 mg of drug powder was incubated for 3 h at 140 °C prior to the first extraction and thermostatted for 15 min at 140 °C between each extraction. Extraction was carried out with 2 μL of dimethyl sulfoxide (DMSO) as the microdrop for 5 min. The features of the method were established using standard solutions. Validation of the proposed method showed good agreement with the traditional dissolution method for analysis of residual solvents in drug product. The results indicated that MHS-SDME has a great potential for the quantitative determination of residual solvents directly from the solid drug products due to its low cost, ease of operation, sensitivity, reliability and environmental protection.

Infrared-assisted extraction coupled with high-performance liquid chromatography for simultaneous determination of eight active compounds in Radix Salviae miltiorrhizae

Co-reporter:Yile Chen;Gengli Duan;Meifen Xie;Bin Chen

Journal of Separation Science 2010 Volume 33( Issue 17-18) pp:2888-2897

Publication Date(Web):

DOI:10.1002/jssc.201000234

Abstract

In this study, a novel infrared-assisted extraction (IRAE) method, in which infrared radiation was employed to extract the active compounds from plant, was developed and coupled with HPLC for simultaneous determination of four phenolic acids and four diterpenoids in Radix Salviae miltiorrhizae (Chinese name Danshen). The extraction conditions of IRAE were optimized and the optimal conditions were as follows: extraction time of 15 min; extraction solvent of 70% v/v methanol in water solution, and solid/liquid ratio of 0.1:15 (g/mL). Chromatography was performed on a 200 mm×4.6 mm id, 5-μm particle size, C18 column. Good linearity (r>0.9994) was observed over the concentration ranges investigated, and intra-day and inter-day precision were high. Recoveries of the eight compounds were from 96.90 to 104.30% and RSD was below 2.5%. By using this novel IRAE method, with a shorter extraction time, the determined amounts of the eight active components in Danshen were comparable with or even higher than those extracted with conventional heat-reflux extraction and ultrasound-assisted extraction methods and microwave-assisted extraction. The developed IRAE method is simple, low-cost and efficient, offering a great promise for quick determination of active compounds in natural plants.

Nitrogen-protected microwave-assisted extraction of ascorbic acid from fruit and vegetables

Co-reporter:Yingjia Yu;Bin Chen;Yile Chen;Meifen Xie;Haotian Duan;Gengli Duan

Journal of Separation Science 2009 Volume 32( Issue 23-24) pp:4227-4233

Publication Date(Web):

DOI:10.1002/jssc.200900487

Abstract

In this study, nitrogen-protected microwave-assisted extraction (NPMAE), in which microwave-assisted extraction was performed under nitrogen protection, was initially developed and combined with HPLC separation for the determination of ascorbic acid (AA), an oxidizable component, from fruit and vegetables. The extraction conditions of NPMAE were investigated by extraction of AA from guava, and the chosen conditions were as follows: extraction solvent of 0.25% metaphosphoric acid solution, solid/liquid ratio of 1:10 g/mL, microwave power of 400 W and irradiation time of 10 min. Subsequently, this novel NPMAE method was evaluated by extraction of AA from different fruit and vegetables, such as guava, yellow pepper, green pepper and cayenne pepper. Compared with conventional MAE and solvent extraction methods, the oxidation of AA was significantly reduced or prevented in the process of NPMAE, providing higher extraction yield of AA. These results suggested the potential of NPMAE method for the extraction of oxidizable compounds from different spices of matrices.