To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was...To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was reviewed. MSS has been coupled to sweeping FASS, FASI and normal EKI. Furthermore, multiple stacking by coupling MSS with more than one stacking method has also been reported. It is more sensitive and selective than solely used of one or two stacking methods and is very suitable for complex and trace sample analysis.展开更多
The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been propos...The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described..An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol （volume fraction is 55%, the same below）, in turn, then eluted by an eluent containing 50% ethanol and 0.25 M（mol/dm^3） H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4 85.7 aM, and the LOD （3a） was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.展开更多
A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters ...A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.展开更多
A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodio...A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodiode array detection. Under the optimal conditions, the calibration curve was linear over a range of 0.5-40μg·mL^-1 for CBZ with a correlation coefficient of 0.998. The detection limit （S/N = 3：1） of CBZ was 0.10 μg·mL^-1. The sweeping-MEKC method has been successfully applied to the analysis of CBZ in human serum.展开更多
为提升家用雾化制氧机的用户体验及满意度,提出结合用户体验模型,采用半结构化访谈方式归纳用户需求并建立评价层级体系;采用序关系分析法进行需求指标权重计算及优度排序;通过功能分析系统技术(Function Analysis System Technique,FA...为提升家用雾化制氧机的用户体验及满意度,提出结合用户体验模型,采用半结构化访谈方式归纳用户需求并建立评价层级体系;采用序关系分析法进行需求指标权重计算及优度排序;通过功能分析系统技术(Function Analysis System Technique,FAST)功能树获取产品功能要素,指导设计方案输出;采用模糊综合评价(Fuzzy Comprehensive Evaluation,FCE)法对产品设计方案进行用户满意度评价。研究结果表明:基于序关系分析法和FCE法设计的家用雾化制氧机具有较高的用户满意度,设计方法的集成提升了用户需求获取与方案评价环节的效率及科学性,可为同类产品的创新设计提供参考。展开更多
通过LabVIEW软件编译,与FIAlab for Windows软件结合,分别控制光纤光谱仪和微顺序注射-阀上实验室(MicroSIA Lab-on-valve,μSIA-LOV)系统,以光纤作为传导介质,将光纤光谱仪、微顺序注射分析仪和氘灯光源连接,基于样品的紫外吸收特性,...通过LabVIEW软件编译,与FIAlab for Windows软件结合,分别控制光纤光谱仪和微顺序注射-阀上实验室(MicroSIA Lab-on-valve,μSIA-LOV)系统,以光纤作为传导介质,将光纤光谱仪、微顺序注射分析仪和氘灯光源连接,基于样品的紫外吸收特性,实现原位待测样品溶液浓度随时间变化的实时在线监测。编译光谱采集模块,进行样品溶液的光谱扫描,实现对物质的定性分析;编译标准曲线模块,实现对物质的定量分析方法的建立;编译样品检测模块,实现样品溶液浓度的实时连续测定。并以头孢氨苄为例,基于紫外吸收测定模式的LabVIEW软件编译的3个模块,同时对待测样品进行原位和过程分析,与紫外分光光度计测得结果比较(P>0.05),结果无显著性差异。说明LabVIEW软件编译的3个模块可实现待测溶液浓度的原位实时连续监测。展开更多
文摘To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was reviewed. MSS has been coupled to sweeping FASS, FASI and normal EKI. Furthermore, multiple stacking by coupling MSS with more than one stacking method has also been reported. It is more sensitive and selective than solely used of one or two stacking methods and is very suitable for complex and trace sample analysis.
基金The National High Technology Research and Development Program of China under contract Nos 2006AA09Z174 and 2007AA061501the National Natural Science Foundation of China under contract No. 40521003
文摘The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described..An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol （volume fraction is 55%, the same below）, in turn, then eluted by an eluent containing 50% ethanol and 0.25 M（mol/dm^3） H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4 85.7 aM, and the LOD （3a） was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.
基金sponsored by the Natural Science Foundation of Hebei (Nos.B2006000413,B2008000210).
文摘A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.
文摘A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodiode array detection. Under the optimal conditions, the calibration curve was linear over a range of 0.5-40μg·mL^-1 for CBZ with a correlation coefficient of 0.998. The detection limit （S/N = 3：1） of CBZ was 0.10 μg·mL^-1. The sweeping-MEKC method has been successfully applied to the analysis of CBZ in human serum.
文摘通过LabVIEW软件编译,与FIAlab for Windows软件结合,分别控制光纤光谱仪和微顺序注射-阀上实验室(MicroSIA Lab-on-valve,μSIA-LOV)系统,以光纤作为传导介质,将光纤光谱仪、微顺序注射分析仪和氘灯光源连接,基于样品的紫外吸收特性,实现原位待测样品溶液浓度随时间变化的实时在线监测。编译光谱采集模块,进行样品溶液的光谱扫描,实现对物质的定性分析;编译标准曲线模块,实现对物质的定量分析方法的建立;编译样品检测模块,实现样品溶液浓度的实时连续测定。并以头孢氨苄为例,基于紫外吸收测定模式的LabVIEW软件编译的3个模块,同时对待测样品进行原位和过程分析,与紫外分光光度计测得结果比较(P>0.05),结果无显著性差异。说明LabVIEW软件编译的3个模块可实现待测溶液浓度的原位实时连续监测。
