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Chen B.,Zhanjiang Normal University | Chen B.,Development Center for New Materials Engineering and Technology in Universities of Guangdong | Zhang Y.,Zhanjiang Normal University | Xie H.-L.,Zhanjiang Normal University | And 2 more authors.
Journal of the Chinese Chemical Society | Year: 2014

We describe a chiral separation method for ofloxacin enantiomers, levofloxacin and dextrofloxacin by microchip capillary electrophoresis with capacitively coupled contactless conductivity detection. The running buffer included 1 mmol L-1 MES and 1 mmol L-1 Tris (pH 8.0) with a separation voltage of 1.5 kV and an injection time of 10s. Under these conditions, the enantiomers were completely separated within 1 min. The linear calibration curves were A = 5.76 c - 0.00587 for levofloxacin and A = 5.41 c - 0.00551 for dextrofloxacin, in which the linear concentration of the components all ranged from 0.05 to 0.15 mg mL-1 (regression coefficients were both 0.9996). The limits of detection (S/N = 3) were, respectively, 18 and 21 μg mL-1. The relative standard deviations of migration time were both 2.0% (n = 6). The relative standard deviations of peak area were 3.4% (n = 6) for levofloxacin and 4.0% (n = 6) for dextrofloxacin. The effects of some factors on resolutions, such as separation voltage and injection time, concentration of running buffers, were studied. The method was simple, rapid, high-efficient. Furthermore, the method could be applied to the chiral separation of the product containing these enantiomers, such as Ofloxacin Eye Drops. Ofloxacin enantiomers, levofloxacin and dextrofloxacin in Ofloxacin Eye Drops were separated by microchip capillary electrophoresis with capacitively coupled contactless conductivity detection. The proposed method is a simple and scientific innovation to evaluate and control the quality of fluoroquinolones antibiotic drugs. Copyright © 2014 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany.


Chen B.,Zhanjiang Normal University | Chen B.,Development Center for New Materials Engineering and Technology in Universities of Guangdong | Mai Q.,Zhanjiang Normal University | Chen Q.,Zhanjiang Normal University
Journal of Liquid Chromatography and Related Technologies | Year: 2014

A method of microfluidic chip with contactless conductivity detection has been developed for the determination of ofloxacin in Ofloxacin Ear Drops. Electrophoresis conditions included a buffer of 1m mol L-1L-Histidine (pH 6.5) with 1m mol L-1 2-(N-Morpholino)ethanesulfonic acid (MES), an applied voltage of 1.5 kV, and an injection time of 10s with a voltage of 500V. Under optimum conditions, the component was determined within 0.7min, allowing detection of ofloxacin in Ofloxacin Ear Drops. The regression equation was y = 669767x-1364.4 and the square of correlation coefficients (r 2) was 0.9997. The linear range of the component was from 0.1 to 0.8 mg mL-1. The relative standard deviations (RSD, n = 3) for migration time and peak area were 0.9%and 4.0%, respectively. The detection limit (S/N = 3), 21.2 mg L-1, was low. The average recovery of the component was 101.7%(RSD = 4.6%, n = 3) by this method. This developed method is rapid, high efficient, sensitive, economical, and capable of the determining the active ingredient in Ofloxacin Ear Drops. © 2014 Copyright Taylor & Francis Group, LLC.


Tang X.S.,Zhanjiang Normal University | Tang X.S.,Development Center for New Materials Engineering and Technology in Universities of Guangdong | Wang H.J.,Zhanjiang Normal University | Feng L.,Zhanjiang Normal University | And 4 more authors.
Applied Surface Science | Year: 2014

Mo (molybdenum) doped diamond like carbon (Mo-DLC) coatings with improved mechanical and blood compatibility properties were deposited by closed field unbalanced magnetron sputtering. The undoped and Mo-doped DLC coatings were analyzed by various characterization techniques such as Raman spectra, Atomic force microscopy, and temperature-dependent frictional wear testing. The results showed that the Mo-DLC coating with low Mo concentration was a effective protective coating with reduced residual stress and increased cohesive strength, and kept good wear resistance at the ambient temperature of 500 °C. The blood compatibility of Mo-DLC coatings was investigated by platelet adhesion. The results showed that the amount of thrombus on the Mo-DLC nanocomposite coatings was much less than that of thrombus on pyrolytic carbon films. The Mo-DLC nanocomposite coatings would be a new kind of promising materials applied to artificial heart valve and endovascula stent. © 2014 Elsevier B.V.

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