LC Analysis of Isepamicin in Plasma Samples Post-Inhalation with Fluorescence Detection and Its Application to a Pharmacokinetic Study

A simple and novel LC method has been developed for determination of isepamicin (ISP) in rat plasma, an aminoglycoside antibiotic agent. After protein precipitation and clean-up procedure to remove lipophilic contaminants, ISP is derivatized by pre-column with 9-fluorenylmethyl chloroformate for fluorescence detection. Chromatographic separations are achieved using a C18 column and mobile phase consisting of water and acetonitrile (68/32, v/v). Amikacin was used as an internal standard. The calibration curve was linear over a concentration range of 0.625–15 μg mL^?1. The limit of quantification was 0.45 μg mL^?1. The intra- and inter-day variabilities of ISP were both less than 5%. Both derivatives were stable for at least a week at ambient condition. This assay procedure should have useful application in therapeutic drug monitoring of ISP. The limit of detection was 0.10 μg mL^?1. The specificity, assay linearity, low level assay linearity and assay repeatability were also investigated. The established method provides a reliable bioanalytical method to carry out isepamicin pharmacokinetics in rat plasma.     

老鼠血清中苯扎贝特的HPLC-MS法测定

建立一种简便、快速、灵敏的高效液相色谱-质谱联用测定老鼠血清中苯扎贝特的方法。 采用Gemini C18色谱柱;流动相：V(乙腈)∶V(甲醇)∶V(水)=60∶15∶25(0.03%甲酸水溶液);柱温35 ℃,流速0.3 mL/min;紫外吸收波长为235 nm;进样量5 μL。 质谱采用电喷雾电离负离子模式,用于定量分析的离子分别为[M-H]- m/z 359.65→273.70(苯扎贝特)和[M-H]- m/z 212.95→127.08(氯贝酸)。 对苯扎贝特检测的线性范围为0.073~7.884 mg/L,r=0.9995。 得到苯扎贝特的平均回收率为94.3%~103.1%;方法的日内和日间的相对标准偏差(RSD)均小于6%;最低检测限(LOD)与定量限(LOQ)分别为9.0和30 μg/L;为临床上人体血清中苯扎贝特的浓度检测提供了一种重现性好、灵敏度高的分析方法。     

RuH2和RuN2电子组态与光谱性质的从头计算

用量子化学从头算方法在B3LYP/6 311G 的水平上 ,研究了RuH2 和RuN2 可能的电子组态和光谱性质 .结果表明 ,RuH2 的3 B2 和5Σ-态对应于静电作用的物理吸附态 .RuN2 的一重态和三重态的计算结果跟钌单晶面上的实验值相接近 .而RuN2 在C∞v对称性时 ,五重态5Σ-的计算频率比实验值稍低 .在C2v对称性时 ,五重态的计算频率值则更低 ,3 B2 和5A1态不能稳定存在     

催化裂解CH4制备碳纳米管的影响因素

以柠檬酸法制备的Fe MgO、Co MgO和Ni MgO为催化剂 ,CH4 为碳源气 ,H2 为还原气 ,在 873、973和 10 73K制备出碳纳米管 ,通过TEM和拉曼光谱表征 ,讨论了催化剂、制备温度、反应时间等因素对碳纳米管形貌、产率和内部结构的影响 .结果表明 :不同的催化剂在相同的温度下制备的碳纳米管的形态和内部结构有很大的差异 .其中Fe MgO催化剂制备的碳纳米管管径粗 ,且大小不均匀 ,而Ni MgO催化剂制备的碳纳米管管径较细、较均匀 .碳纳米管的产率随着裂解温度的变化而改变 .Fe MgO催化剂制备碳纳米管的产率随制备温度的升高而提高 ,而Ni MgO催化剂制备碳纳米管的产率随制备温度的升高而降低 .Fe MgO催化剂制备碳纳米管 ,在10 73K甚至更高的制备温度才能达到其最高产率 .Co MgO催化剂制备碳纳米管的产率在 973K左右产率较高 ,而用Ni MgO催化剂制备碳纳米管 ,则在 873K甚至更低的制备温度就能达到最高产率 .反应时间与碳纳米管的产率不成正比 ,有一最佳反应时间 ,如Ni MgO催化剂的最佳反应时间为 2h .     

裂变碎片动能和质量分布的三维朗之万研究

采用一个具有协变形式的朗之万方程组来描述不对称热核裂变.基于核表面｛c,h,α｝三参数模型,用数值方法模拟了核系统从鞍点到断点的扩散过程,从而完成了碎片动能和质量分布的计算.研究了核的两体摩擦或一体耗散机制以及有限颈部作为核断裂条件对裂变碎片输出量的影响.     

缓蚀剂在阳极电泳涂装中的应用

在电泳涂装工艺中使用缓蚀剂，可提高阳极电泳涂层的防腐蚀性，实验表明，沥青电泳漆与缓蚀剂的电泳共沉积涂层对基底金属具有较高的防护性能，探讨了共沉积涂层中缓蚀剂的缓蚀机理。     

Optimal reactions for the synthesis of superheavy nucleus 270Hs

The superheavy nucleus ²⁷⁰Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions ²⁴⁸Cm(²⁶Mg,4n)²⁷⁰Hs, ²⁴⁴Pu(³⁰Si,4n)²⁷⁰Hs, ²³⁸U(³⁶S,4n)²⁷⁰Hs and ²²⁶Ra(⁴⁸Ca,4n)²⁷⁰Hs using a two-parameter Smoluchowski equation. It is found from our results that ²²⁶Ra(⁴⁸Ca,4n)²⁷⁰Hs and ²³⁸U(³⁶S,4n)²⁷⁰Hs are two optimal reactions for the synthesis of the superheavy nucleus ²⁷⁰Hs due to their large negative Q-values.     

Electrochemical determination of nitrite using a gold nanoparticles-modified glassy carbon electrode prepared by the seed-mediated growth technique.

Seed-mediated growth of gold nanoparticles on glassy carbon (GC) surfaces was developed. The field emission scanning electron microscopy (FE-SEM) and electrochemical characterization confirmed the effective attachment of gold nanoparticles on GC surface with such a wet-chemical method. The as-prepared gold nanoparticles attached glassy carbon electrode (Au/GCE) presented excellent catalytic ability toward the oxidation of nitrite. Compared with bare GCE and planar gold electrode, the Au/GCE obviously decreased the overpotential of nitrite oxidation and improved the peak current. The catalytic current was found to be linearly proportional to the nitrite concentration in the range of 1 x 10(-5) - 5 x 10(-3) M, with a detection limit of 2.4 x 10(-6) M. The Au/GCE was successfully applied to the electrochemical determination of nitrite in a real wastewater sample, showing excellent stability and anti-interference ability.