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Yu S.,Dalian Elite Analytical Instruments Co. | Feng S.,Dalian Elite Analytical Instruments Co. | Sun Y.,Dalian Elite Analytical Instruments Co. | Tang T.,Dalian Elite Analytical Instruments Co. | And 3 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2011

A method of quantitative analysis of sulfur amino acids in feedstuffs by high performance liquid chromatography coupled with pre-column derivatization was developed. Before the feedstuffs were hydrolyzed under acidic condition; the cystine and methionine in the feedstuffs were oxidized to cysteic acid and methionine sulfone respectively by performic acid, and then derivatized by 2,4-dinitrofluorobenzene. The separation was performed on an Elite AAK C18 column (250 mm × 4. 6 mm, 5μm) by the gradient elution of 0. 05 mol/L sodium acetate and acetonitrile-water (50: 50, v/v) as the mobile phase with a flow rate of 1. 2 mL/min at 31°C. The detection wavelength was set at 360 nm. The linearities of cystine and methionine were good in the ranges of 0. 4 - 16. 0 mg/L and 0. 7 - 29. 6 mg/L with the correlation coefficients of 0. 999 9 and 0. 999 8, respectively. The quantification limits (S/N = 10) were 2. 6μg/kg, 3. 1μg/kg, and the recoveries were 100. 28% - 102. 00% and 105. 72% - 107. 89%, respectively. The method can be adapted to the accurate quantification of the sulfur amino acids in feedstuffs.


PubMed | Tohoku University, Dalian Ocean University, CAS Institute of Process Engineering and Dalian Elite Analytical Instruments Company Ltd
Type: | Journal: Glycoconjugate journal | Year: 2016

Epithelial-mesenchymal transition (EMT) is a process in tumor progression during which cancer cells undergo dramatic changes acquiring highly invasive properties. In a widespread adoption of TGF--induced EMT model, we have previously observed that expression of bisecting GlcNAc on N-glycans was dramatically decreased. Herein, we performed in vitro studies with the MCF10A cell line. In response to low cell density, MCF10A cells suffered spontaneously morphologic and phenotypic EMT-like changes, including elongated spindle shape, extended out from edge of the cell sheet, cytoskeleton reorganization, vimentin and fibronectin up-regulation, catenins redistribution, and cadherin switching. Moreover, these phenotypic changes were associated with specific N-glycan alterations. Interestingly, the amounts of bisecting GlcNAc structure were declined, by contrast, the formation of 1-6 GlcNAc branches were obviously up-regulated during the EMT induced by sparse cell conditions. We further investigated N-glycans on the 1-integrin, which is a good target of some glycosyltransferases. The reactivity with E4-PHA lectin decreased, whereas the staining for L4-PHA lectin, which recognizes branched GlcNAc, increased in sparse cell conditions compared with dense cell conditions. Taken together, these results demonstrated that specific N-glycan alterations are coupled in EMT process and promoted cells migration at a low cell density.


PubMed | Tohoku University, Dalian Ocean University, CAS Institute of Process Engineering and Dalian Elite Analytical Instruments Company Ltd
Type: | Journal: Cell biology international | Year: 2016

Epithelial-mesenchymal transition (EMT) is a phenomenon in cancer progression during which cancer cells undergo remarkable alteration acquiring highly invasive property. The aim of this study was to evaluate specific N-glycan alterations during EMT induced by epidermal growth factor (EGF) in GE11 epithelial cells. Herein, we demonstrated that EGF activated epidermal growth factor receptor (EGFR)/Akt/extracellular signal-regulated kinase (ERK) phosphorylation and promoted GE11 cell proliferation. Meanwhile, EGF stimulated the epithelial cells to undergo morphological alteration, destroying cell-cell inter-contact and exhibiting mesenchymal cells higher metastatic potential. A wound-healing assay showed the migratory ability increased 1.5-fold after EGF treatment. Moreover, the relative intensity of N-cadherin versus E-cadherin increased 2.6-fold, and the E-cadherin distribution in cell-cell junctions became jagged and faint after EGF incubation for 72h. Interestingly, the amounts of bisecting GlcNAc structure were dramatically declined, by contrast, the formation of 1,6 GlcNAc branches on cell surface was upregulated during EMT induced by EGF. To understand the roles of N-glycans in EGF-induced EMT, the cells were stably transfected with N-acetylglucosaminyltransferase III (GnT-III), which catalyzes the bisecting GlcNAc structure formation. As the markers for EMT, EGF-induced E-cadherin decrease and fibronectin increase were delayed in GnT-III-overexpressing cells. Taken together, these results demonstrated that specific N-glycan alterations were coupled in EMT induced by EGF, which might be contributed to diagnosis and therapy of tumor metastasis.


Li S.,Dalian Elite Analytical Instruments Co. | Feng S.,Dalian Elite Analytical Instruments Co. | Chen Y.,Dalian Elite Analytical Instruments Co. | Li T.,Dalian Elite Analytical Instruments Co. | Li T.,Liaoning Dalian Elite Analytical Instruments Engineering Research Center
Chinese Journal of Chromatography (Se Pu) | Year: 2014

An analytical method for the determination of the activity of transglycosidase in dia-static enzyme by high performance liquid chromatography (HPLC) was established. Taken as the substrate, maltose was transformed into trisaccharide by transglycosidase in a 37 °C water bath and acetic acid buffer solution (PH = 4. 8) with acarbose as transglycosidase inhibitor. The transformation of the trisaccharide was detected on a SUGAR SH1011 column (300 mm × g.O mm, 6 μm) with 0. 01 mol/L sulfuric acid solution as mobile phase at a flow rate of 0. 6 mL/min and a differential refractive index detector (RID), in order that the activity of transglycosidase can be measured indirectly. The conditions such as the chromatographic conditions, the concentration of substrate, the usage of inhibitor, and the incubation time were investigated. Under the optimized separation conditions, the calibration curve of the trisaccharide showed good linearity within the mass concentrations of 0. 1-10 g/L (r=0. 999 8). The limit of detection and the limit of quantitation for transglycosidase activity were 0. 013 U and 0. 043 U, respectively. The relative standard deviation was 0. 63% for six parallel tests. The activities of transglycosidase from different batches of diastatic enzyme were also determined with good result. The method can be applied to determine the activity of transglycosidase in the diastatic enzyme of the producers' raw materials with the advantages of convenience, simplicity and stability.


Zhao B.,Nanjing University of Science and Technology | Zhang Y.,Nanjing University of Science and Technology | Tang T.,Nanjing University of Science and Technology | Tang T.,Dalian Elite Analytical Instruments Co. | And 4 more authors.
Progress in Chemistry | Year: 2012

High performance liquid chromatography is not only a useful analytical technique, but also an effective preparation method. The availability of a variety of stationary phases for column has been a key factor in the development of HPLC as a major scientific tool. With the most desirable compromise of properties that provide for effective and reproducible separations, silica has been the most widely used HPLC packing material. The silica microspheres are synthesized by various methods, including spray drying, sol-gel, polymerization induced colloid aggregation and templating methods. In recent years, atypical types of silica are prepared and applied in HPLC, such as sub-2μm silica particles, superficially porous silica particles, bimodal silica particles, mesoporous silica particles, organic/silica hybrid particles, etc. As a result, unique separation properties that enlarge the capabilities of HPLC methods have been achieved, such as ultrahigh-pressure liquid chromatography based on sub-2μm silica particles, fast liquid chromatography based on superficially porous silica particles, high temperature liquid chromatography based on organic/silica hybrid particles. Moreover, novel stationary phase can be obtained by chemical bonding or polymer modification of silica surface, such as chiral stationary phase, temperature-responsive stationary phase and restricted access materials. In this paper, the preparation methods and modification modes of silica particles are introduced, as well as the characterization methods of HPLC stationary phase. The applications of silica packing material in HPLC and its developing trends are also outlined.


Zhao B.,Henan University of Technology | Zhang Y.,Nanjing University of Science and Technology | Tang T.,Nanjing University of Science and Technology | Tang T.,Dalian Elite Analytical Instruments Co. | And 3 more authors.
Particuology | Year: 2015

Abstract Ultra-pure mesoporous silica microspheres with good monodispersity were synthesized in two steps: nanometer-sized silica sol was produced by the sol-gel process, then micrometer-sized silica microspheres were synthesized by polymerization-induced colloid aggregation of the silica sol. The total metal content of the microspheres was extremely low, which eliminated the tailing of chromatographic peaks by chelating reagents. The pore structure of the silica microspheres could be controlled by altering the sol-gel conditions. The silica microsphere particle size could be adjusted by using different polymerization-induced colloid aggregation conditions. © 2014 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.


Zhao B.B.,Henan University of Technology | Wang F.Y.,Nanjing University of Science and Technology | Li T.,Dalian Elite Analytical Instruments Co.
Asian Journal of Chemistry | Year: 2015

Micrometer-sized mesoporous silica particles have been synthesized by a modified polymerization induced colloid aggregation method. Silica particles with particle size in the range of 2-5 μm could be obtained by controlling the reaction conditions. The obtained silica particles were characterized by scanning electron microscopy (SEM), N2 physisorption technique and inductively coupled plasma emission spectroscopy (ICP-AES). The C18-modified silica particles were explored as stationary phase in reversed phase liquid chromatography and its chromatographic characteristics for separation of some small molecules have been studied.


Yang S.,Nanjing University of Science and Technology | Tang T.,Nanjing University of Science and Technology | Tang T.,Dalian Elite Analytical Instruments Co. | Li T.,Dalian Elite Analytical Instruments Co. | And 2 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2016

The optical absorption detector is one of the most commonly used detectors for high performance liquid chromatography (HPLC). As a core part of this kind of detector, the designs of flow cells, where light passes through samples for acquiring samples information, will affect the performance of a detector. In order to enhance the signal to noise ratio of detectors and reduce the bands broadening that come from flow cells, it is necessary to design a flow cell with a longer optical path length and a less cell volume while maintaining the luminous flux. However the limitations of the machining capacity make it difficult to increase the optical path length, reduce the cell volume and keep or increase the luminous flux simultaneously. It is a challenge to optimize the designing and machining of flow cells so as to improve the performance of detectors. This review discusses the development of designing flow cells based on the detection principle in some aspects of increasing the optical path length, reducing the cell volume, taking the advantages of total reflection and so on. At the same time, some of the designs are illustrated in detail. These various ideas and structures are significant references for designing flow cells and developing optical absorption detectors.


PubMed | East China University of Science and Technology and Dalian Elite Analytical Instruments Co.
Type: Journal Article | Journal: Se pu = Chinese journal of chromatography | Year: 2014

A sensitive high performance liquid chromatography (HPLC)-laser induced fluorescence detection (LIFD) method was developed for the determination of amines. The derivatization and separation conditions were investigated. Under the optimized conditions, spermidine, putrescine and histamine were analyzed. The limits of detection (LODs) of the three biogenic amines (S/N = 3) were as low as 10(-10) mol/L. This method showed excellent stability. The RSDs of retention times and peak areas of the three biogenic amines were lower than 0.3% and 3%, respectively. This method was applied in biogenic amine analysis in water samples, and the average recoveries were in the range of 94.99%-104.7%. Furthermore, the amines in seven tea samples were analyzed by this method, and satisfactory results were achieved. The developed assay is of excellent sensitivity and good reproducibility, which can be used in the analysis of the amines in water samples.


PubMed | Nanjing University of Science and Technology and Dalian Elite Analytical Instruments Co.
Type: Journal Article | Journal: Se pu = Chinese journal of chromatography | Year: 2014

A new kind of silica-bonded reserved stationary phase with s-triazine and amide polar groups embedded for HPLC was obtained by step-wise reactions of silica gel with s-triazine, gamma-aminopropyltriethoxysilane, ethanediamine and dodecanoyl chloride. The new stationary phase was characterized by elemental analysis. After that, a column packed with the new stationary phase was used to separate basic compounds. A commercial C18 column was also tested under the same chromatographic conditions for comparison. The results indicated that the ligand was successfully bonded to the surface of the silica and the maximum relative deviations of element contents were within 5% for carbon, nitrogen and hydrogen by three times. Furthermore, in the separation of five basic anilines and four basic pyridines, the excellent selectivity and symmetrical peak shapes provided a reference for advancing the commercialization of the new stationary phase.

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