The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples ...The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples based on preconcentration with mini-column packed with MWNTs prior to its determination by flame atomic absorption spectrometry （FAAS） The recommended parameters of proposed method influencing the preconcentration of the analytes, such as pH of the sample, sample flow rate and volume, elute solution and interfering ions, have been used. Under the optimized conditions, the calibration graphs were linear with the correlation coefficient range 0.9981-0.9995. According to the results, the metals were found 0.019-0.051, 0.011-0.031, 0.00-0.081, 0.00-0.0002, 0.007-0.0925, 0.00-0.0104 μg/L in water samples for Pb, Mn, Zn, Cd, Fe, Cu respectively. The percentage relative standard deviation （%RSD） for five replicate samples were 〈 5% in all cases. The method has been successfully applied to the determination of trace elements in some environmental samples with satisfactory results.展开更多
目的:建立测定以脂肪乳为载体地塞米松滴眼液中药物在各相中的分布和包封率方法,并分析其作为载药性能评价指标的可行性。方法:根据脂质乳中相密度差异,在8℃、30000 r·min^(-1)离心力下分离在油、水及油水界面相中的药物;依据凝...目的:建立测定以脂肪乳为载体地塞米松滴眼液中药物在各相中的分布和包封率方法,并分析其作为载药性能评价指标的可行性。方法:根据脂质乳中相密度差异,在8℃、30000 r·min^(-1)离心力下分离在油、水及油水界面相中的药物;依据凝胶分子筛原理对脂质乳滴表面的游离药物和包封于乳滴中的药物进行柱分离;色谱条件:采用Sun Fire C_(18)色谱柱(250 mm×4.6 mm,5μm),以乙腈-水(28∶72)为流动相,流速1.0 m L·min^(-1),检测波长240 nm,柱温30℃,进样量20μL。结果:水相、油相、油水界面磷脂层中地塞米松的占比为42.43%、31.12%、24.45%,体系中地塞米松的包封率为50.11%。结论:相分布和包封率指标合用能准确评价脂肪乳的载药性能,所建立的方法可作为以脂肪乳为载体滴眼液的质量控制的手段之一。展开更多
文摘用一个阴离子树脂交换性能微柱连续测定系统(MCCD),在动态条件下考察影响大孔型强碱阴离子树脂性能的各种因素,得到了测定其交换容量的最佳参数:柱长度为60 mm,内径3.0 mm;树脂层高度40 mm,填充量为0.1720 g;再生剂NaOH浓度3%,流速0.6 m l/m in,再生剂耗量为433 m l/g(树脂);样品水为20 mg/L酸性氯离子溶液,流速1.3 m l/m in。在最佳参数下,对各种大孔型强碱阴离子树脂、凝胶型树脂、均粒与非均粒树脂的交换性能进行了测定和对比;MCCD法与国标法的相关系数为r=0.990,它具有试剂耗量少、操作简单、自动化程度高等优点,通过一次测定,可同时给出树脂的工作交换容量、平衡交换容量、全交换容量、交换速率、利用率等多个参数。
文摘The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples based on preconcentration with mini-column packed with MWNTs prior to its determination by flame atomic absorption spectrometry （FAAS） The recommended parameters of proposed method influencing the preconcentration of the analytes, such as pH of the sample, sample flow rate and volume, elute solution and interfering ions, have been used. Under the optimized conditions, the calibration graphs were linear with the correlation coefficient range 0.9981-0.9995. According to the results, the metals were found 0.019-0.051, 0.011-0.031, 0.00-0.081, 0.00-0.0002, 0.007-0.0925, 0.00-0.0104 μg/L in water samples for Pb, Mn, Zn, Cd, Fe, Cu respectively. The percentage relative standard deviation （%RSD） for five replicate samples were 〈 5% in all cases. The method has been successfully applied to the determination of trace elements in some environmental samples with satisfactory results.
文摘目的:建立测定以脂肪乳为载体地塞米松滴眼液中药物在各相中的分布和包封率方法,并分析其作为载药性能评价指标的可行性。方法:根据脂质乳中相密度差异,在8℃、30000 r·min^(-1)离心力下分离在油、水及油水界面相中的药物;依据凝胶分子筛原理对脂质乳滴表面的游离药物和包封于乳滴中的药物进行柱分离;色谱条件:采用Sun Fire C_(18)色谱柱(250 mm×4.6 mm,5μm),以乙腈-水(28∶72)为流动相,流速1.0 m L·min^(-1),检测波长240 nm,柱温30℃,进样量20μL。结果:水相、油相、油水界面磷脂层中地塞米松的占比为42.43%、31.12%、24.45%,体系中地塞米松的包封率为50.11%。结论:相分布和包封率指标合用能准确评价脂肪乳的载药性能,所建立的方法可作为以脂肪乳为载体滴眼液的质量控制的手段之一。
