JOURNAL OF CHROMATOGRAPHY A
·
2021
·
IF 4.759
Houmei Liu,Pian Jin,Mi Jiang,Yu Duan,Guozheng Zhu,Hui Yu,Hongdeng Qiu
In this work, for the first time five amine-ligands including mono-amine, di-amine, tri-amine, secondary and tertiary amine, were functionalized on mesoporous micro-silicas and developed as stationary phases for hydrophilic interaction liquid chromatography (HILIC). The investigations about the retention mechanisms, effects of different chromatographic conditions and stability were systematically conducted. Three kinds of polar and hydrophilic compounds (saccharides, sulfonamides, nucleosides and nucleobases) were selected as probe molecules to evaluate their separation performances. Among the five stationary phases, only aminopropyl-bonded silica has already gained wide developments and applications. Whereas, there are no related researches about the other four to be utilized as separation media. By a series of chromatographic evaluations, the results revealed the other four mesoporous micro-silica materials functionalized with di-amine, tri-amine, secondary and tertiary amine, had great potential to be explored as novel stationary phases of HILIC. Particularly, the two stationary phases functionalized with di-amine and tri-amine exhibited outstanding separation and retention abilities. This work offered some insights on the understanding of retention in HILIC mode and provided us possibility to explore other amine-based HILIC stationary phases.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2021
·Vol. 25
·期 4
·1383-1391
·
IF 2.647
Yang Hongmei,Hu Peiyu,Tang Jing,Cheng Ying,Wang Fang,Chen Zilin
A simple and sensitive bifunctional electrochemical aptasensor for detection of adenosine and thrombin has been developed using gold nanoparticles–electrochemically reduced graphene oxide (AuNPs-ERGO) composite film-modified electrode. Firstly, the reduced graphene oxide film and AuNPs were sequentially immobilized on glassy carbon electrode (GCE) surface. Secondly, thrombin aptamer was immobilized on the modified electrode. Finally, adenosine aptamer was hybridized with it to serve as a recognition element and methylene blue (MB) as electrochemical signal indicator. In the presence of adenosine or thrombin, the sensor recognized it and a conformational change was induced in aptamer, resulting in decrease of the peak current of MB. The linear relation between concentration of adenosine or thrombin and peak current of MB allowed quantification of them. Thanks to the special electronic characteristic of AuNPs-ERGO composite film, sensitivity of sensor was greatly improved. Under optimal conditions, the proposed aptasensor presented an excellent performance in a linear range of 25 nM to 750 nM for adenosine and 0.5 nM to 10 nM for thrombin. Detection limits were estimated to be 8.3 nM for adenosine and 0.17 nM for thrombin, respectively. Moreover, dual-analyte detection of adenosine and thrombin was achieved without potentially increasing the complexity and cost of the assay.
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JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Jincai Wang,Jialiang Guo,Haowen Chen,Xiaoling Huang,Govert W. Somsen,Fenyun Song,Zhengjin Jiang
A single-step copolymerization strategy was developed for the preparation of carbohydrate (glucose and maltose) functionalized monoliths using click reaction. Firstly, novel carbohydrate-functionalized methacrylate monomers were synthesized through Cu(I)-catalyzed 1,3-dipolar cycloaddition (alkyne-azide reaction) of terminal alkyne with azide of carbohydrate derivatives. The corresponding carbohydrate functionalized monolithic columns were then prepared through a single-step in-situ copolymerization. The physicochemical properties and performance of the fabricated monolithic columns were evaluated using scanning electron microscopy, Fourier-transform infrared spectroscopy, and nano-liquid chromatography. For the optimized monolithic column, satisfactory column permeability and good separation performance were demonstrated for polar compounds including nucleoside, phenolic compounds and benzoic acid derivatives. The monolithic column is also highly useful for selective and efficient enrichment of glycopeptides from human IgG tryptic digests. This study not only provided a novel hydrophilic column for separation and selective trapping of polar compounds, but also proposed a facile and efficient approach for preparing carbohydrate functionalized monoliths.
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Analytical Methods
·
2020
·Vol. 12
·期 46
·5635-5641
·
IF 2.596
Dan Liu,Lili Meng,Liping Huang,Shipeng Luo,Guohua Zhang
Chitosan is a considerably versatile and promising biomaterial and can easily form a 3D hierarchical porous scaffold. In this work, a novel boronate-affinity monolithic column modified with a boronic acid–chitosan complex was prepared and characterized by different methods such as Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis, specific surface area analysis and pore size distribution analysis. The synthesized monolithic column was used for polymer monolithic microextraction combined with high performance liquid chromatography for the simultaneous determination of cytidine, uridine, inosine, and guanosine in milk powder samples. Several parameters affecting extraction efficiency, including the eluent proportion, eluent flow rate, sample flow rate, sample volume, and sample pH were investigated. The boronate-affinity monolithic column showed high enrichment ability due to the selective formation of cyclic borate esters between nucleosides and boronic acid groups at high pH and the release of cyclic borates at low pH values. Under the optimum operating conditions, the linear range was 0.1–50 μg mL−1, and the correlation coefficients were in the range of 0.9993–0.9994. The LOD and LOQ were in the range of 0.0027–0.0034 and 0.0090–0.011 μg mL−1, respectively. In addition, the results of recovery and relative standard deviation were satisfactory.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 7
·1-11
·
IF 6.232
Ma Mingxuan,Du Yingxiang,Zhang Liu,Gan Jie,Yang Jiangxia
A β-Cyclodextrin covalent organic framework (β-CD COF) was successfully prepared under ambient temperature with a mild chemistry strategy from heptakis(6-amino-6-deoxy)-β-cyclodextrin and terephthalaldehyde. It was embedded into the poly[(glycidyl methacrylate)-co-(ethylene dimethacrylate)] [poly(GMA-co-EDMA)] monolith and served as the β-CD COF material–incorporated monolith. The synthetic materials were characterized by field emission scanning electron microscopy, energy-dispersive X-ray mapping analysis, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and N 2 adsorption-desorption isotherm. The β-CD COF material–incorporated monolith achieved baseline separation in capillary electrochromatographic separation of three amides, three amino acids, three nucleosides, four aromatic acids, and three positional isomers (with resolution values of three amides, 1.75 and 1.54; three amino acids, 5.24 and 1.75; three nucleosides, 2.56 and 1.77; four aromatic acids, 6.96, 2.74, and 1.64; three positional isomers, 1.61 and 1.50). In comparison with the original monolith, the β-CD COF material–incorporated monolith shows significantly enhanced resolution for mixed molecules. The effect of pH and concentration of buffer and applied voltage were discussed in detail. The fabricated monolith showed good stability and reproducibility (relative standard deviation (RSD) < 6.9%). Molecular modeling illuminated the interactions between the small molecules and stationary phase, and provided a sufficient theoretical basis for experimental data.
Schematic presentation of the preparation of β-cyclodextrin covalent organic framework (β-CD COF) material–incorporated organic polymer monolith for separating the amides, amino acids, nucleosides, aromatic acids, and positional isomers. β-CD COF materials were synthesized and incorporated into the monolith as the stationary phase. Then, the incorporated monolith was applied in the capillary electrochromatography system for separating small molecules.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2020
·Vol. 412
·期 12
·2981-2991
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IF 3.637
Dai Min,Ma Ting,Niu Ying,Zhang Mengmeng,Zhu Zhiwu,Wang Shaomin,Liu Hongmin
GC/MS coupled metabolomics analysis, using a simplified and much less expensive silylation process with trimethylsilyl cyanide (TMSCN), was conducted to investigate metabolic abnormalities in stomach cancer cells. Under optimized conditions for derivatization by TMSCN and methanol extraction, 228 metabolites were detected using GC/MS spectrometry analysis, and 89 metabolites were identified using standard compounds and the NIST database. Ten metabolite levels were found to be lower in stomach cancer cells relative to normal cells. Among those ten metabolites, four metabolites—ribose, proline, pyroglutamic acid, and glucose—were known to be linked to cancers. In particular, pyroglutamic acid level showed a drastic reduction of 22-fold in stomach cancer cells. Since glutamine and glutamic acid are known to undergo cyclization to pyroglutamic acid, the 22-fold reduction might be the actual reduction in the levels of glutamine and/or glutamic acid—both known to be cancer-related. Hence, the marked reduction in pyroglutamic acid level might serve as a biomarker to aid early detection of stomach cancer.
Graphical abstract
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 3
·1-10
·
IF 6.232
Guo Rui,Wang Dan-Ni,Wei Yun-Yun,Zhang Ying-Zhi,Yang Chun-Guang,Xu Zhang-Run
A controllable approach for preparing a portable colloidal photonic crystal (CPC) array chip is presented. The approach was inspired by the confinement effect of nanoparticle self-assembly on patterned surface. Hydrophobic polydimethylsiloxane substrate with reproducible micro-region array was fabricated by soft-lithography. The substrate was employed as the patterned template for self-assembly of monodisperse polystyrene nanoparticles. The CPC units can be prepared in several minutes, and exhibit consistent reflection wavelength. By adjusting the size of polystyrene nanoparticles and the shape of micro-regions, CPC units with multiple structure, colors and geometries were obtained. The CPC array chip features fluorescence enhancement owing to the optical modulation capability of the periodic nanostructure of the self-assembled CPC. With the reflection wavelength (523 nm) of green CPC units overlapping the emission wavelength (520 nm, with excitation wavelength of 490 nm) of 6-carboxyfluorescein-labeled DNA probe, the fluorescence intensity increased more than 10-fold. For signal-amplified assay of adenosine, the concentration range of linear response was 5.0 × 10 −5 mol L −1 to 1.0 × 10 −3 mol L −1 , and the limit of detection was 1.3 × 10 −6 mol L −1 . Because of the enhancement effect of photonic crystal, the fluorescence images were more readable from the CPC array chip, compared with those from the planar substrate. The chip has potential applications in multiplex determination with high-throughput via encoding strategy based on the tunable structure, color or geometric shape.
Schematic diagram of signal-enhanced fluorescent detection of adenosine based on the colloidal photonic crystal array chip (PDMS, polydimethylsiloxane; PS NPs, polystyrene nanoparticles; CPC, colloidal photonic crystal; GO, graphene oxide; FAM, 6-carboxyfluorescein).
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 27
·11704-11709
·
IF 3.288
Chao Fan,Hao Tang,Licheng Wang,Yijing Li,Xusheng Wang,Shuai Wang,Xiaojing Liang
Using N-isopropylacrylamide (NIPAM) as a monomer, a core–shell material was successfully prepared via in situ polymerization on the surface of silica microspheres (named NIPAM@Sil), which acts as a hydrophilic interaction chromatography (HILIC) stationary phase. A method for the in situ polymerization of polymer monomers on a silica surface has been developed. It was shown using scanning electron microscopy (SEM) that NIPAM is evenly distributed on the surface of the silica. The synthesized NIPAM@Sil possesses a polar acylamino group arising from the polymerization of NIPAM. As demonstrated by the hydrophilicity, NIPAM@Sil showed excellent HILIC performance for the separation of hydrophilic compounds. This method provides a simple approach for the preparation of a polymer coated silica core–shell stationary phase.
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JOURNAL OF CHROMATOGRAPHY A
·
2021
·
IF 4.759
Chao Fan,Bei Liu,Hui Li,Kaijun Quan,Jia Chen,Hongdeng Qiu
In this work, three new mixed-mode stationary phases were prepared, based on different ratio of N-vinyl pyrrolidone (NVP) copolymerized together with undecylenic acid (UA) on silica microspheres surface without silanization, which named Sil@NVPUA series. The combination of NVP and UA rendered the Sil@NVPUA suitable for reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), and shown excellent methyl, planar, isomers and ion selectivity. Five types of model analytes including eight polycyclic aromatic hydrocarbons, six alkylbenzenes, eight nucleosides and nucleobases, seven ginsenosides and five oxazolidinones can be well separated on this stationary phase. The preparation method of NVP and UA modified silica-based stationary phase is simple, and it also provides a new idea for the design of synthetic polymers to develop mixed-mode chromatography.
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高影响因子
MOLECULES
·
2019
·Vol. 24
·期 22
·4119
·
IF 3.06
Zhonghua Dong,Yueyue Sun,Guangwei Wei,Siying Li,Zhongxi Zhao
Cordyceps Sinensis, a traditional Chinese medicine and a healthy food, has been used for the treatment of kidney disease for a long time. The aim of present study was to isolate a nucleoside/nucleobase-rich extract fromCordyceps Sinensis(CS-N), determine the contents of nucleosides and nucleobases, and explore its anti-diabetic nephropathy activity. CS-N was isolated and purified by using microporous resin and glucan columns and the unknown compounds were identified by using HPLC-DAD and LC-MS. The effects of CS-N on the epithelial–mesenchymal transition (EMT), extracellular matrix (ECM) depositions, and the MAPK signaling pathway were evaluated in streptozotocin (STZ)-induced diabetic mice and high glucose (HG)-exposed HK-2 cells. CS-N significantly attenuated the abnormity of renal functional parameters, ameliorated histopathological changes, and inhibited EMT and ECM accumulation by regulating p38/ERK signaling pathways. Our findings indicate that CS-N exerts a therapeutic effect on experimental diabetic renal fibrosis by mitigating the EMT and the subsequent ECM deposition with inhibition of p38 and ERK signaling pathways.Keywords:nucleosides and nucleobases;diabetic nephropathy;HK-2 cells;extracellular matrix;epithelial–mesenchymal transition
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ANALYTICA CHIMICA ACTA
·
2019
·
IF 5.256
Shuangshou Wang,Zhendong He,Wenzhi Li,Jiayi Zhao,Tong Chen,Shimin Shao,Hongmei Chen
Pipette tip-based solid phase extraction (PT-SPE) has been proved to be an effective and user-friendly separation technique due to its miniaturized procedure and practical convenience. However, the vast majority of existing PT-SPE devices consist of a filter-sorbents-filter sandwich structure, which may suffer the unforeseen risk of sorbents leakage caused by the looseness of filters. More importantly, many high-capacity nanosorbents with particle size smaller than pore size of filters are unavailable. Thus, sorbent packing-free and sample low-consumption PT-SPE could be a more robust strategy for separation and detection, but such a possibility has not been explored yet. Herein we report a tubing reshaping strategy for facile fabrication of sorbent packing-free PT-SPE devices. Three types of reshaped PTs, namely stretched tube-like, self-crimping and filter in-built PTs, were fabricated via simple heating and stretching operations. The reshaped PTs exhibited flexible surface chemical post-modification. The SPE process was directly performed in reshaped PTs with an obviously enhanced extraction efficiency compared to once-shaping PTs while no need of packing sorbents. Extraction of nucleosides from human urine by boronic acid-functionalized reshaped PTs was demonstrated. Our findings technically renovate the structural composition of PT-SPE devices. As PTs are inexpensive and high-plasticity, the sorbent packing-free SPE scheme presented herein could find more promising applications and provides a new perspective for design and fabrication of novel sorbent packing-free SPE devices.
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JOURNAL OF CHROMATOGRAPHY A
·
2019
·
IF 3.858
Tianpei Cai,Haijuan Zhang,Jia Chen,Zhan Li,Hongdeng Qiu
A new strategy based on synergistic effect of the carbon dots and their precursor was proposed to enhance the selectivity of hydrophilic interaction liquid chromatography (HILIC). In this work, polyethyleneimine (PEI) and PEI-functionalized carbon dots (PEICDs) mix-grafted silica packing material was prepared to act as a novel HILIC stationary phase. Both inner and outer surface of the porous silica are decorated with the mixture of PEI and carbon dots. This stationary phase, namely Sil-PEI/CDs, demonstrate enhanced retention ability and selectivity toward polar analytes, with which 11 nucleosides and nucleobases and 9 ginsenosides can be nicely separated. The Sil-PEI/CDs (RSD 0.12% – 0.54%) exhibited even better stability than the traditional PEI modified stationary phase (RSD 0.39% – 0.87%) within 40 h of continuously elution. And excellent column efficiency was observed from Sil-PEI/CDs (∼65,000 plates/m for cytidine). The strategy of mixed stabilization revealed a new method to prepare good performanced carbon dots based chromatographic column.
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