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Yang X.,Beijing Institute of Technology | Liu Z.,Beijing Institute of Technology | Xie Y.,Shandong Pesticide Research Institute | Zhang Q.,Beijing Institute of Technology
Polymer Science - Series A | Year: 2015

Sodium salt of styrene/methacrylic acid copolymer was synthesized via radical polymerization, and its absolute molecular mass and polydispersity index were measured by aqueous-based GPC coupled with MALLS in a mixed solvent containing 75/25, v/v%, methanol/water, 38.6 mM NaCl and 10.0 mM NaH2PO4 buffer, pH 6.0. Dynamic light scattering verified the absence of aggregation of copolymer in preferred mobile phase compositions. © 2015, Pleiades Publishing, Ltd. Source

Xu Q.,Shandong University | Zong W.,Shandong Normal University | Shi L.,Shandong Pesticide Research Institute | Liu R.,Shandong University
Spectroscopy Letters | Year: 2013

The mobile proton model has been the main theory to describe peptide fragmentation in mass spectrometry (MS). In this study, Gly-Ala-Tyr (GAY) was used to research the mass spectrometry cleavage mechanism. The hydroxyl radical oxidation technique was applied to change the charge distribution of the peptide. We applied MS/MS technique to obtain the tandem mass spectrum of the peptide and then obtained fragmentation efficiency curves, which indicated that the cleavage of GAY became more and more difficult as more O atoms were added. The charge distribution was obtained from quantum chemical calculations at the B3LYP/6-31G(d) level using the Gaussian 03 W program. By analyzing the charge distribution around the amide bonds, we found that the total charge of C and N atoms (QC + QN) in the amide bonds provided a reasonable prediction of peptide fragmentation efficiency. A decrease of the QC + QN value in the amide bonds leads to a low fragmentation efficiency of GAY, and vice versa. Through comparing experimental data with calculation results to research the relationship between charge distribution and the mass spectrometry cleavage mechanism, this work provides a new way to understand the mobile proton model for peptide fragmentation. © 2013 Taylor & Francis Group, LLC. Source

Du K.,University of Jinan | Liu W.,Shandong Pesticide Research Institute | Qiao S.,University of Jinan | Zhou C.,University of Jinan | Cao W.,University of Jinan
Journal of Inorganic and Organometallic Polymers and Materials | Year: 2011

It is found that nucleic acids can greatly enhance the fluorescence intensity of morin-nanoTiO 2. Under optimum conditions, the enhanced fluorescence intensity of the system is in proportion to the concentration of nucleic acids in the range of 2.0 × 10 -8 to 2.2 × 10 -7 g mL -1 for calf thymus DNA (ctDNA) and 1.0 × 10 -8 to 2.5 × 10 -7 g mL -1 for yeast RNA (yRNA). The detection limits are 4.8 × 10 -9 g mL -1 for ctDNA and 1.2 × 10 -9 g mL -1 for yRNA, respectively. This method has satisfactorily been used for the determination of nucleic acids in actual sample. © 2011 Springer Science+Business Media, LLC. Source

Gong P.X.,University of Jinan | Liu W.H.,Shandong Pesticide Research Institute | Liu W.W.,University of Jinan | Du K.,University of Jinan | And 2 more authors.
Advanced Materials Research | Year: 2011

A simple, sensitive and rapid method for flow injection with chemiluminescence analysis has been developed for the determination of prednisone acetate at trace level. This method is based on the luminescent properties of the tris(1,10-phenanthroline) ruthenium(II)-potassium permanganate -prednisone acetate in acidic medium sensitized by Na2SO 3. The optimized experimental conditions are evaluated. Under the optimum experimental conditions, the linear ranges of prednisone acetate are: 4.0×10-10∼4.0×10-8 g·mL -1 and 4.0×10-8∼2.0×10-7 g·mL-1 with a low detection limit is 4.5×10 -11 g·mL-1 and the relative standard deviation for 1.0×10-8 g·mL-1 sample is 1.04% (n=11). The proposed method has been successfully applied to the determination of prednisone acetate in tablets. © (2011) Trans Tech Publications. Source

Liu W.,University of Jinan | Liu W.,Shandong Pesticide Research Institute | Mu X.,University of Jinan | Gong P.,University of Jinan | Cao W.,University of Jinan
Advanced Materials Research | Year: 2011

A flow injection chemiluminescence (CL) method has been developed for the determination of indoleacetic acid (IAA). It is based on the fact that the weak CL of Ce(IV)-Ru(phen)3 2+ system is strongly enhanced in the presence of silver nanoparticles. Optimum conditions and possible mechanisms have been investigated. Under optimum experimental conditions, the linear range is from 1.0×10-8-6.0×10-7 g mL-1 with a detection limit 9.0×10-9 g mL-1. © (2011) Trans Tech Publications, Switzerland. Source

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