Abstract A new method was described for simultaneous determination of ciprofloxacin (CIP), ofloxacin (OFL) and norfloxacin (NOR) by capillary electrophoresis with a diode array detector at 280 nm. The separation conditions were investigated and optimized. A new medium, 30 mM sodium tetraborate buffer solution and 22 mM sodium dodecyl sulphate containing 5% (v/v) methanol (pH 8.7), was developed for the complete separation of the three quinolones. The excipients do not affect to separation and analysis. Calibration curves between peak area and concentration in the range 10-1000 mg/L for each compound have good linearity with a correlation coefficient (r) of greater than 0.999, and the detection limit£¨s/n£© was 7.90 mg/L for CIP£¬7.92 mg/L for OFL and 7.56 mg/L for NOR. This method has been successfully applied for simultaneous determination of CIP, OFL and NOR in the pharmaceutical preparations with rapid, accurate, and simple characteristics.
Keywords Capillary electrophoresis; Ciprofloxacin; Ofloxacin; …

Sui Chaoxia¹, Yang Fang^1,2, Zheng Wenjie^1,2, Bai Yan¹
(¹ Department of Chemistry, Jinan University; ² Research Center of Hydrobiology, Jinan University, 510632, China)

Received Dec. 24, 2005; Supported by the National Natural Science Foundation of China (No.20271022) and Guangdong Natural Science Foundation (No.010369)

Abstract A series of complexes CuL₂Cl₂ (L= NS, MB, BS) were synthesized, based on the liquid-phase reaction of piazselenole(NS), 5-methyl- piazselenole(MB), 4,5-benzopiazselenole(BS), which acted as ligands and Cu²⁺ as cation. The physicochemical properties of the complexes were determined by ICP-AES, EA, FT-IR analysis, UV-Vis, XRD, FS etc. The coordination mechanism between ligands and Cu²⁺ was also discussed.
Keywords heterocyclic aromatic selenium compounds, copper complexes, synthesis and characterization

Selenium is the trace element controlled by gene in human body^[1]. Heterocyclic aromatic selenium compounds (Piaselenole, Pis) are a sort of important compounds derived by …

Ren Longliang, Cui Jinhua^#
( Department of Physics, Science College, Tianjin University,  Tianjin 300072; ^# Department of Chemistry, Liaoning Normal University, Dalian 116021 )

Abstract Optical emission spectra in CH₄+H₂ discharge plasma system with high voltage and high frequency pulse at atmospheric pressure was preliminarily diagnosed in order to optimize discharge condition for CH₄ coupling under plasmas. It was shown that CH, CH₂ and C₂ radicals were main species in the system. Spectral intensity of C₂ swan band at 50 W of supplied power was higher than that at 72 W. Cathode sputtering and black-body radiation increased with the increase of the supplied power for the discharges.
Keywords Plasma, methane coupling, optical emission spectrum diagnoses

Spectral lines abound in optical spectrogram of plasma emission, from visible light to ultraviolet radiation and even to X-rays. The emission is caused by motion of numerous …

Du Qishi ^a*, Wang Shuqing ^a, Wei Dongqing ^a, Li Aixiu^a,b
(^aInstitute of Bioinformatics and Drug Discovery, Tianjin Normal University; ^bMedical College of Chinese People’s Armed Police Forces, Tianjin, 300162)

Abstract In this research we calculate the correlation coefficients and analyze the correlation relationship among 20 amino acids in 4 type proteins (a, b, a/b, and a+b), total 204 proteins. Our research shows that amino acid correlations can be divided into strong positive correlation, strong negative correlation, weak correlation, and no-correlation. The correlation relationships of amino acids in 4 type proteins are quite different, and represent the protein’s structure characters. We analyze the relationship between amino acid correlation and the structure of proteins and give explanation for the physicochemical origins of amino acid correlations.
Keywords Amino acids; Protein structure; Bioinformatics; Chemometrics

Amino Acid Correlation in Proteins and Its Application in Structural Analysis

Du …

Liu Yi^{1, 2} Sun Dayuan¹ Yu Yuhe² Qu Songsheng¹ Shen Yunfen²
(¹Department of Chemistry, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072,  China; ²Laboratry of Protozoology, Institute of Hydrobiology, Chinese Academy of Science, Wuhan 430072,  China)

Received Sep.6, 2001; Supported by the National Natural Science Foundation of China (NSFC), and Young Mainstay Teachers’ Program of Chinese Educational Ministry.

Abstract The heat output of the growth metabolism of Tetrahymena pyriformis has been determined by using a LKB-2277 BioActivity Monitor at 25°C. From the thermogenic curves, it can be established that thermokinetic equation of their growth metabolism is P_t = P_t=0 exp(k_m t),   dP / dt = k_m P¹ ,with the order of growth metabolism n = 1. The experimental results indicate that the relationship between the metabolic power (P) and …