A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis （CE） was described. In order to improve the sensitivity, two online concentration techniques including ca...A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis （CE） was described. In order to improve the sensitivity, two online concentration techniques including cation-selective exhaustive injection （CSEI） and sweeping micellar electrokinetic chromatography （sweeping-MEKC） were used. Under the optimum conditions, the detection limits （S/N = 3） were 0.10 μg/L for ephedrine and 0.80 μg/L for codeine. This method was successfully applied to real urine sample analysis.展开更多
An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-s...An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-step processes of Mn+ + Yn? (s: solid phase) MY(s) and MY(s) + 2X? X2MY2?(s) (n = 1, 2) at a test solution/electrode-interface were considered as a model. Here, Mn+, Yn?, and X? refer to a divalent or univalent cation, functional groups of electrode materials, and a halide ion (X? = Cl?, Br?, I?), respectively. By applying electrochemical potentials to these processes at n = 2, we derived an equation. Regression analyses based on the equation reproduced well the plots of emf versus log 2(*[M]t) for the Cd(II) and Cu(II) systems: *[M]t denotes a total concentration of species relevant to M2+ in a bulk of the aqueous solution. Also, we obtained log Ks(CdBr2) = 4.28 ? 0.22, log Ks(CdI2) = 6.98 ? 0.05, log Ks(CuCl2) = 3.96 ? 0.09, and log Ks(CuBr2) = 11.4 at 25?C. The magnitude in ?log Ks reflected that in the logarithmic solubility product, log {*[M2+](*[X?])2}, for bulk water, where *[M2+] or *[X?] denotes a molar concentration of the bulk solu-tion of M2+ or X? at equilibrium, respectively. Moreover, a mixture of CuSO4 with NaCl at the molar ratio of 1:1 yielded a plot similar to that of CuCl2.展开更多
With the impact of energy crisis and environmental problems,it is urgent to develop green sustainable energy.Osmotic energy stored in the salinity difference between seawater and river water is one of the sustainable,...With the impact of energy crisis and environmental problems,it is urgent to develop green sustainable energy.Osmotic energy stored in the salinity difference between seawater and river water is one of the sustainable,abundant,and renewable energy.However,the membranes used to capture osmotic energy by reverse electrodialysis(RED)always suffer from low ion selectivity,low stability and low power.Hydrogels with three-dimensional(3D)networks have shown great potential for ion transportation and energy conversion.In this work,based on the homogeneity and porosity characteristics of acrylamide(AM)hydrogel,as well as the remarkable stability and abundant negative charge of 3-sulfopropyl acrylate potassium salt(SPAK),a high-performance AM/SPAK cation-selective hydrogel membrane was successfully developed for harvesting osmotic energy.Compared to AM hydrogels,utilizing AM/SPAK as a monomer mixture greatly facilitated the preparation of homogeneous polymers,exhibiting a porous structure,exceptional ion selectivity,and remarkable stability.A maximum output power density of 13.73 W/m^(2)was achieved at a 50-fold NaCl concentration gradient,exceeding the commercial requirement of 5 W/m^(2).This work broadens the idea for the construction and application of composite hydrogel in high efficiency osmotic energy conversion.展开更多
基金supported by the Guangxi Provincial Foundation of Natural Science(No.0481019).
文摘A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis （CE） was described. In order to improve the sensitivity, two online concentration techniques including cation-selective exhaustive injection （CSEI） and sweeping micellar electrokinetic chromatography （sweeping-MEKC） were used. Under the optimum conditions, the detection limits （S/N = 3） were 0.10 μg/L for ephedrine and 0.80 μg/L for codeine. This method was successfully applied to real urine sample analysis.
文摘An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-step processes of Mn+ + Yn? (s: solid phase) MY(s) and MY(s) + 2X? X2MY2?(s) (n = 1, 2) at a test solution/electrode-interface were considered as a model. Here, Mn+, Yn?, and X? refer to a divalent or univalent cation, functional groups of electrode materials, and a halide ion (X? = Cl?, Br?, I?), respectively. By applying electrochemical potentials to these processes at n = 2, we derived an equation. Regression analyses based on the equation reproduced well the plots of emf versus log 2(*[M]t) for the Cd(II) and Cu(II) systems: *[M]t denotes a total concentration of species relevant to M2+ in a bulk of the aqueous solution. Also, we obtained log Ks(CdBr2) = 4.28 ? 0.22, log Ks(CdI2) = 6.98 ? 0.05, log Ks(CuCl2) = 3.96 ? 0.09, and log Ks(CuBr2) = 11.4 at 25?C. The magnitude in ?log Ks reflected that in the logarithmic solubility product, log {*[M2+](*[X?])2}, for bulk water, where *[M2+] or *[X?] denotes a molar concentration of the bulk solu-tion of M2+ or X? at equilibrium, respectively. Moreover, a mixture of CuSO4 with NaCl at the molar ratio of 1:1 yielded a plot similar to that of CuCl2.
基金financial support by the National Natural Science Foundation of China(No.21805017)。
文摘With the impact of energy crisis and environmental problems,it is urgent to develop green sustainable energy.Osmotic energy stored in the salinity difference between seawater and river water is one of the sustainable,abundant,and renewable energy.However,the membranes used to capture osmotic energy by reverse electrodialysis(RED)always suffer from low ion selectivity,low stability and low power.Hydrogels with three-dimensional(3D)networks have shown great potential for ion transportation and energy conversion.In this work,based on the homogeneity and porosity characteristics of acrylamide(AM)hydrogel,as well as the remarkable stability and abundant negative charge of 3-sulfopropyl acrylate potassium salt(SPAK),a high-performance AM/SPAK cation-selective hydrogel membrane was successfully developed for harvesting osmotic energy.Compared to AM hydrogels,utilizing AM/SPAK as a monomer mixture greatly facilitated the preparation of homogeneous polymers,exhibiting a porous structure,exceptional ion selectivity,and remarkable stability.A maximum output power density of 13.73 W/m^(2)was achieved at a 50-fold NaCl concentration gradient,exceeding the commercial requirement of 5 W/m^(2).This work broadens the idea for the construction and application of composite hydrogel in high efficiency osmotic energy conversion.
