Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a n...Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.展开更多
A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cel...A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10-1-10-3 mol L-1 and the concentration ratio CK+ / CNa+. was 10:1 to 1:50. When the concentration ratios were equal to 1and the total electrolyte concentrations were 10-2 and 10-3 mol L-1, the ion activity ratio measurement would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively. Ions other than H+ have no remarkable influence on the measurement. The ion activity ratio of K+ to Na+ measured directly in soil suspension agree well with those in centrifuged supernant solution. The relative deviation was within 4%. From the measured ion activity ratio, the difference of the bonding energies of K+ and Na+ ions was calculated.展开更多
CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sol-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted comple...CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sol-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted completely at lower temperature. The redox behavior and the crystallization process of the dried gel were studied by thermogravimetric analysis and infrared spectroscopy. The synthesized powders were characterized by X-ray powder diffraction and transmission electron microscopy. In addition, rare earth elements ion-selective electrodes based on acetyl cellulose were prepared using ultra fine cerium oxide powders.展开更多
A novel Ce（Ⅳ） ion-selective polyvinyl chloride（PVC） membrane electrode based on HDEHP and HEH/EHP as ionophore was successfully prepared. The factors affecting the response of Ce（Ⅳ） ion were investigated, such...A novel Ce（Ⅳ） ion-selective polyvinyl chloride（PVC） membrane electrode based on HDEHP and HEH/EHP as ionophore was successfully prepared. The factors affecting the response of Ce（Ⅳ） ion were investigated, such as membrane composition, internal solution, concentration of SO_4^（2–）, and acidity in test solution. The best performance was obtained using the membrane with PVC：DBP：HDEHP：HEH/EHP：OA mass ratio of 75：175：5：5：5. The proposed electrode exhibited a Nernstian slope of 30.44 mV/decade for Ce（Ⅳ） ion over a linear concentration range of 1×10^（–5）–1×10^（–1） mol/L with the detection limit of 9.0×10^（-6） mol/L. The electrode showed stable response within the SO_4^（2–） concentration range of 0.1–1 mol/L and the acidity range of 0.25–1.2 mol/L H＋. The proposed electrode showed high selectivity for Ce（Ⅳ） over a wide variety of interfering ions and a fast response time. It was used as an indicator in the potentiometric titration of Ce（Ⅳ） solution with H_2O_2 solution, and could also be used for the determination of Ce（Ⅳ） in real Ce（Ⅳ）-containing aqueous samples.展开更多
A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet o...A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet of urea-formaldehyde resin containing Cl - ions to form a needle-shaped inner reference electrode, then the inner reference electrode was coated with a thin sheet of a PVC membrane containing an enoxacin tetraphenylborate ion-pair complex. The influences of various ion-pair complexes, concentrations of the active components in the membrane and the plasticizers on the performance of the electrode were studied by orthogonal design. The linear response range of the electrode was 7.9×10 -5 -1.0×10 -2 mol/L. The detection limit was 2.0×10 -5 mol/L. The slope was 30.4 mV/decade(25 ℃). The electrode can be used for the potentiometric determination of enoxacin tablets directly. The average recovery was 100.4%, and the RSD was 0.9%. The results agreed with those determined by the method in Chinese Pharmacopoeia.展开更多
A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion e...A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.展开更多
A new PVC matrix membrane double-barreled calcium ion-selective microelectrode based on liquid ion exchanger has been designed and constructed.The tip diameter of about 2.5μm as well as lower selectivity coefficients...A new PVC matrix membrane double-barreled calcium ion-selective microelectrode based on liquid ion exchanger has been designed and constructed.The tip diameter of about 2.5μm as well as lower selectivity coefficients for K+,Na and Mg2+are adequate for in-tracellular measurements of Ca activities.The inner wall of the selective channel was made to be hydrophobic by treatment withalkyl-alcohols.By means of this microelectrode some physiologicalphenomena related to Ca2+activities have been studied,and Caconcentrations in clinical microsamples have also been determined.展开更多
Enzyme was immobilized on an ammonium ion-selective electrode by different methods.An ion-selective electrode is not completely ion-specific,and interfering ions react with the ion-selective electrode membrane,alterin...Enzyme was immobilized on an ammonium ion-selective electrode by different methods.An ion-selective electrode is not completely ion-specific,and interfering ions react with the ion-selective electrode membrane,altering the measured potential.Therefore,the characteristics of the effect of other ions on ammonium ion-selective electrode-based urea biosensors are considered.Based on the experimental results,the urea biosensor based on entrapment had a high response voltage of around 189 mV and fast response time of around 16 sec.Moreover,selectivity of the urea biosensor in different interfering ions was considered to elucidate the characteristics of ammonium ion-selective electrode-based biosensors.展开更多
A calcium ion-setective eletrode based on a new neutral carrier was studied.The electrode gives a Nernstian response in the rang 5.9-1 Pa and the response is stable in a wide pH range.Logarithms of setectivity coeffic...A calcium ion-setective eletrode based on a new neutral carrier was studied.The electrode gives a Nernstian response in the rang 5.9-1 Pa and the response is stable in a wide pH range.Logarithms of setectivity coefficents are -2.3 Li(+),-3.5 Na(+),-4.0 K(+),-3.7NH_4(+),-4.5 Mg(2+) and -4.4Zn(2+).展开更多
Using environment-friendly and low-cost biowaste adsorbents as toxic metal ion removal substrates from aqueous solutions has a great economic advantage. This work evaluated pumpkin and potato peel biowastes for the ad...Using environment-friendly and low-cost biowaste adsorbents as toxic metal ion removal substrates from aqueous solutions has a great economic advantage. This work evaluated pumpkin and potato peel biowastes for the adsorption of cadmium ions. The biowastes were treated with acid or base. Batch experiments were carried out by introducing a known concentration of metal ion solution into the biowaste sorbent at various pH levels. The pH and metal ion concentration was monitored with pH and cadmium ion-selective electrode continuously for two hours, and the final concentration for the metal ion after 24 hours was measured with the cadmium electrode and then confirmed with ICP-OES. L-type isotherms were obtained that fit to Freundlich model. Adsorption isotherms showed chemical adsorption and the kinetics following the second order model. Equilibrium adsorption capacity is higher than 29 mg/g at pH 5.6 when the initial concentration is 220 ppm. Dynamic cadmium adsorption capacity is 17 mg/g from aqueous solution when the feed solution is 220 ppm with pumpkin peel biowaste sorbent. The biowaste materials can be regenerated with acid washing.展开更多
Potassium is one of the macro minerals necessary for the cellular functions,obtained from foods.Excessive amounts of potassium can cause health problems.Determination of potassium in various samples,especially food an...Potassium is one of the macro minerals necessary for the cellular functions,obtained from foods.Excessive amounts of potassium can cause health problems.Determination of potassium in various samples,especially food and drug samples,is an important task.In this study,we developed a new potentiometric sensor selective to potassium ions.The sensor had a detection limit of 8.64×10^(-5) M in the concentration range of 1.0×10^(-1)-1.0×10^(-4) M and a near-Nernstian behavior of 49.0±4.32 mV/decade.The sensor exhibited a response time of 10 s,as well as good selectivity,good repeatability,and a wide pH working range(4.0-11.0).The developed sensor was successfully applied to a drug sample and different water samples with very high recoveries(>91.20%).展开更多
Due to their biocompatibility,low operating voltage,and substantial signal amplification capability,ion-selective organic electrochemical transistors(IS-OECTs)show tremendous potential for biofluid-related ion detecti...Due to their biocompatibility,low operating voltage,and substantial signal amplification capability,ion-selective organic electrochemical transistors(IS-OECTs)show tremendous potential for biofluid-related ion detections.However,IS-OECT performances are severely limited by the nonlinear correlation of effective ion-selective membranes(ISMs)potential and effective gate bias demonstrating maximum transconductance(g_(m)),which results in tremendously unstable and degraded current sensitivity(S_(1))in wide ion concentration ranges.Here,by introducing gate bias modulation to ensure the IS-OECTs yield consistent high gm in all ion concentration subranges,a wider detection range and an ultrahigh sensitivity can be simultaneously achieved.Specifically,ascribed to the gate bias modulated from 0.7 to 0.95 V,Ca^(2+)and NH_(4)^(+)-IS-OECTs based on small footprint(640µm^(2))n-type vertical OECTs(vOECTs)possess approximately 3 mA/dec over a wide ionic range of 10^(−5)to 10^(−1)M,respectively,which is the highest SI when compared to ever reported for Ca^(2+)and NH_(4)^(+)ion-sensitive transistors.This work introduces a general approach for ultrahigh sensitivity and wide detection range IS-OECTs,and could be extended to other transistor-based biomolecule and ion sensors,offering valuable insights for advancing high-performance bioelectronics.展开更多
Aqueous zinc-ion batteries have emerged as promising candidates for large-scale energy storage.Despite its potential as a cathode material for AZIBs,H_(2)V_(3)O_(8) suffers from poor electrical conductivity,vanadium d...Aqueous zinc-ion batteries have emerged as promising candidates for large-scale energy storage.Despite its potential as a cathode material for AZIBs,H_(2)V_(3)O_(8) suffers from poor electrical conductivity,vanadium dissolution,and structural instability,which severely compromises its rate performance and cycling stability.To address these limitations,we have developed a polypyrrole-coated H_(2)V_(3)O_(8) composite(H_(2)V_(3)O_(8)@Ppy).Density functional theory calculations demonstrate that Ppy exhibits substantially stronger interactions with HVO_(3)(−1.97 eV)compared to hydrated Zn^(2+) ions(−0.205 eV).This selective interaction enables the Ppy coating to effectively capture dissolved HVO_(3) species while maintaining efficient transport of solvated Zn2+ion clusters,thereby preventing structural degradation of the cathode.The optimized H_(2)V_(3)O_(8)@Ppy cathode delivers an impressive initial capacity of 405 mA h g^(-1) at 100 mA g^(-1) and demonstrates exceptional cycling stability,maintaining nearly 100%capacity retention after 800 cycles at 2 A g^(−1).Furthermore,a quasisolid-state zinc-ion battery incorporating H_(2)V_(3)O_(8)@Ppy cathode exhibits excellent mechanical flexibility and superior longterm cycling performance.Notably,in situ XRD analysis reveals for the first time a two-step phase transformation mechanism of H_(2)V_(3)O_(8) during discharge/charge processes.This study presents an effective strategy for enhancing the structural stability of H_(2)V_(3)O_(8) cathodes in aqueous zinc-ion batteries.展开更多
Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effe...Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho...展开更多
A novel potentiometric detection strategy based on functionalized magnetic nanoparticles has been developed for rapid and sensitive sensing of polyions.Highly dispersed magnetic nanoparticles coated with ion exchanger...A novel potentiometric detection strategy based on functionalized magnetic nanoparticles has been developed for rapid and sensitive sensing of polyions.Highly dispersed magnetic nanoparticles coated with ion exchanger and plasticizer could promote an in situ cooperative ion-pairing interaction between the ion exchanger and the polyion analyte in sample solution by dramatically reducing the mass-transfer distance.With applying a magnetic field,the nanoparticles can be attached to the surface of ion exchanger free polymeric membrane.The observed potential signals are related to the polyion concentrations.The proposed polymeric membrane electrode exhibits a linear relationship between the greatest potential response slope（dE/dt） and the logarithm of protamine concentration in the range of 0.05-5μg/mL with a lower detection limit of 0.033μg/mL.展开更多
15-day old seedlings of wheat and rape were grown in a series of solutions with different concentrations of KNO3 for a definite period of time. The changes in NO3- concentration of the solutions were determined by the...15-day old seedlings of wheat and rape were grown in a series of solutions with different concentrations of KNO3 for a definite period of time. The changes in NO3- concentration of the solutions were determined by the double ion-selective electrode method, and then the amount of NO3- taken up by the plants was estimated and values of Km and Imax of the Michealis-Menten equation were calculated. Results show that both the method and conditions of determination affected the values of Km and Imax. For example, the Km value was appreciably reduced when the volume of culture solution was increased or when the duration of nutrient uptake was shortened; the Km value obtained with short-term depletion method was higher than that obtained with long-term one. Similar Variations were found for the values of Imax. There was a considerable difference in the characteristics of uptake kinetics between wheat and rape when determined under the same conditions of determination. The isotherm of NO3- uptake by wheat could be separated into saturated and unsaturated parts, and when the concentration of NO3- exceeded 180 uuuuuuuuuuuuM, the relationship between the rate of NO3- uptake and NO3- concentration tended to be linear. However, the isotherm of NO3- uptake by rape was found to fit the Michealis-Menten equation and no linear relationship could be found.展开更多
Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electro...Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.展开更多
The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% ...The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% of adsorption on all the samples occurred during the first 5 minutes.All adsorption time-dependent data could fit the surface second-order equation very well.The values of Xm were goethite>kaolinite,and latosol>red soil at the same initial reaction concentration.The values of k were kaolinite>>goethite,and latosol>red soil at the same reaction pH and initial concentration.The higher the suspension pH,the faster the adsorption occurred.The meaning of Xm got by the two ion-selective electrode technique(one kind of batch technique) was different from that by the miscible displacement technique in that the former was only the equilibrium adsorption amount at a definite concentration and pH,but the latter was almost equal to the adsorption capacity at a definite pH with much less influence of concentration.One Pb^2+ was supposed to occupy two adsorption sites as the adsorption mechanism is concerned.展开更多
An ion-selective electrode(ISE)-based immunoassay has been innovatively designed for the sensitive detection of liver cancer biomarker(alpha-fetoprotein,AFP),using metal sulfide quantum dot(QD)-based nano labels.Cd S ...An ion-selective electrode(ISE)-based immunoassay has been innovatively designed for the sensitive detection of liver cancer biomarker(alpha-fetoprotein,AFP),using metal sulfide quantum dot(QD)-based nano labels.Cd S QDs-aggregated PAMAM dendrimer(QD-DE)was first synthesized and functionalized with polyclonal rabbit anti-human AFP antibodies.Thereafter,a sandwich immunoreaction was implemented on monoclonal mouse anti-human AFP antibody-coated microplate by using antibody-functionalized QD-DE as the secondary antibody.Accompanying the immunocomplex,subsequent potentiometric detection of cadmium ion dissolved from the QD-DE under acidic condition was conducted on a portable cadmium ion-selective electrode(Cd-ISE).Results revealed that the electrode potential of the Cd-ISE increased with the increment of AFP concentration from 0.1 to 100 ng m L^(-1)at a detection limit(LOD)of 68 pg m L^(-1).The relative standard deviations(RSD)were below9.09%and 10.54%for the intra-and inter-assay,respectively.Additionally,six human serum specimens were determined on CdISE-based immunosensor by using commercial human AFP ELISA kit as the reference,and gave good relationship between two methods.Importantly,Cd-ISE-based immunoassay offers the promise for simple and cost-effective screening of disease-related biomarkers.展开更多
基金supported by the National Natural Science Foundation of China(30270790).
文摘Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.
文摘A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10-1-10-3 mol L-1 and the concentration ratio CK+ / CNa+. was 10:1 to 1:50. When the concentration ratios were equal to 1and the total electrolyte concentrations were 10-2 and 10-3 mol L-1, the ion activity ratio measurement would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively. Ions other than H+ have no remarkable influence on the measurement. The ion activity ratio of K+ to Na+ measured directly in soil suspension agree well with those in centrifuged supernant solution. The relative deviation was within 4%. From the measured ion activity ratio, the difference of the bonding energies of K+ and Na+ ions was calculated.
基金The work was financially supported by the Project KJCXGC-O1 of Northwest Normal University, Lanzhou and theExcellent Young Te
文摘CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sol-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted completely at lower temperature. The redox behavior and the crystallization process of the dried gel were studied by thermogravimetric analysis and infrared spectroscopy. The synthesized powders were characterized by X-ray powder diffraction and transmission electron microscopy. In addition, rare earth elements ion-selective electrodes based on acetyl cellulose were prepared using ultra fine cerium oxide powders.
基金supported by the Key Program of National Natural Science Foundation of China(50934004)National Natural Science Foundation of China(51274061)+1 种基金Major State Basic Research Development Program of China(2012CBA01205)Fundamental Research Supporting Project of Northeastern University(N110602006)
文摘A novel Ce（Ⅳ） ion-selective polyvinyl chloride（PVC） membrane electrode based on HDEHP and HEH/EHP as ionophore was successfully prepared. The factors affecting the response of Ce（Ⅳ） ion were investigated, such as membrane composition, internal solution, concentration of SO_4^（2–）, and acidity in test solution. The best performance was obtained using the membrane with PVC：DBP：HDEHP：HEH/EHP：OA mass ratio of 75：175：5：5：5. The proposed electrode exhibited a Nernstian slope of 30.44 mV/decade for Ce（Ⅳ） ion over a linear concentration range of 1×10^（–5）–1×10^（–1） mol/L with the detection limit of 9.0×10^（-6） mol/L. The electrode showed stable response within the SO_4^（2–） concentration range of 0.1–1 mol/L and the acidity range of 0.25–1.2 mol/L H＋. The proposed electrode showed high selectivity for Ce（Ⅳ） over a wide variety of interfering ions and a fast response time. It was used as an indicator in the potentiometric titration of Ce（Ⅳ） solution with H_2O_2 solution, and could also be used for the determination of Ce（Ⅳ） in real Ce（Ⅳ）-containing aqueous samples.
文摘A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet of urea-formaldehyde resin containing Cl - ions to form a needle-shaped inner reference electrode, then the inner reference electrode was coated with a thin sheet of a PVC membrane containing an enoxacin tetraphenylborate ion-pair complex. The influences of various ion-pair complexes, concentrations of the active components in the membrane and the plasticizers on the performance of the electrode were studied by orthogonal design. The linear response range of the electrode was 7.9×10 -5 -1.0×10 -2 mol/L. The detection limit was 2.0×10 -5 mol/L. The slope was 30.4 mV/decade(25 ℃). The electrode can be used for the potentiometric determination of enoxacin tablets directly. The average recovery was 100.4%, and the RSD was 0.9%. The results agreed with those determined by the method in Chinese Pharmacopoeia.
基金Supported by the National Natural Science Foundation of China under Grant No 11335003
文摘A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.
基金Projects supported by the science Fund of the Chinese Academy of Sciences.
文摘A new PVC matrix membrane double-barreled calcium ion-selective microelectrode based on liquid ion exchanger has been designed and constructed.The tip diameter of about 2.5μm as well as lower selectivity coefficients for K+,Na and Mg2+are adequate for in-tracellular measurements of Ca activities.The inner wall of the selective channel was made to be hydrophobic by treatment withalkyl-alcohols.By means of this microelectrode some physiologicalphenomena related to Ca2+activities have been studied,and Caconcentrations in clinical microsamples have also been determined.
文摘Enzyme was immobilized on an ammonium ion-selective electrode by different methods.An ion-selective electrode is not completely ion-specific,and interfering ions react with the ion-selective electrode membrane,altering the measured potential.Therefore,the characteristics of the effect of other ions on ammonium ion-selective electrode-based urea biosensors are considered.Based on the experimental results,the urea biosensor based on entrapment had a high response voltage of around 189 mV and fast response time of around 16 sec.Moreover,selectivity of the urea biosensor in different interfering ions was considered to elucidate the characteristics of ammonium ion-selective electrode-based biosensors.
文摘A calcium ion-setective eletrode based on a new neutral carrier was studied.The electrode gives a Nernstian response in the rang 5.9-1 Pa and the response is stable in a wide pH range.Logarithms of setectivity coefficents are -2.3 Li(+),-3.5 Na(+),-4.0 K(+),-3.7NH_4(+),-4.5 Mg(2+) and -4.4Zn(2+).
文摘Using environment-friendly and low-cost biowaste adsorbents as toxic metal ion removal substrates from aqueous solutions has a great economic advantage. This work evaluated pumpkin and potato peel biowastes for the adsorption of cadmium ions. The biowastes were treated with acid or base. Batch experiments were carried out by introducing a known concentration of metal ion solution into the biowaste sorbent at various pH levels. The pH and metal ion concentration was monitored with pH and cadmium ion-selective electrode continuously for two hours, and the final concentration for the metal ion after 24 hours was measured with the cadmium electrode and then confirmed with ICP-OES. L-type isotherms were obtained that fit to Freundlich model. Adsorption isotherms showed chemical adsorption and the kinetics following the second order model. Equilibrium adsorption capacity is higher than 29 mg/g at pH 5.6 when the initial concentration is 220 ppm. Dynamic cadmium adsorption capacity is 17 mg/g from aqueous solution when the feed solution is 220 ppm with pumpkin peel biowaste sorbent. The biowaste materials can be regenerated with acid washing.
文摘Potassium is one of the macro minerals necessary for the cellular functions,obtained from foods.Excessive amounts of potassium can cause health problems.Determination of potassium in various samples,especially food and drug samples,is an important task.In this study,we developed a new potentiometric sensor selective to potassium ions.The sensor had a detection limit of 8.64×10^(-5) M in the concentration range of 1.0×10^(-1)-1.0×10^(-4) M and a near-Nernstian behavior of 49.0±4.32 mV/decade.The sensor exhibited a response time of 10 s,as well as good selectivity,good repeatability,and a wide pH working range(4.0-11.0).The developed sensor was successfully applied to a drug sample and different water samples with very high recoveries(>91.20%).
基金the National Key R&D Program of China(2024YFB3211600)the National Natural Science Foundation of China(62303094,62273073)+7 种基金the National Key R&D Program of China(2023YFC2411800,2022YFE0134800)the Key R&D Program of Henan Province of China(251111221700)the Aeronautical Science Foundation of China(20230024080002)the Sichuan Science and Technology Program(2025ZNSFSC0515)the Chengdu Science Technology Bureau(2023-YF06-00028-HZ)the Key Research Project of the Henan Educational Committee of China(24A413001)the Fundamental Research Funds for the Central Universities(ZYGX2024XJ029)sponsored by the China Postdoctoral Science Foundation(GZB20230116,2024M750343)。
文摘Due to their biocompatibility,low operating voltage,and substantial signal amplification capability,ion-selective organic electrochemical transistors(IS-OECTs)show tremendous potential for biofluid-related ion detections.However,IS-OECT performances are severely limited by the nonlinear correlation of effective ion-selective membranes(ISMs)potential and effective gate bias demonstrating maximum transconductance(g_(m)),which results in tremendously unstable and degraded current sensitivity(S_(1))in wide ion concentration ranges.Here,by introducing gate bias modulation to ensure the IS-OECTs yield consistent high gm in all ion concentration subranges,a wider detection range and an ultrahigh sensitivity can be simultaneously achieved.Specifically,ascribed to the gate bias modulated from 0.7 to 0.95 V,Ca^(2+)and NH_(4)^(+)-IS-OECTs based on small footprint(640µm^(2))n-type vertical OECTs(vOECTs)possess approximately 3 mA/dec over a wide ionic range of 10^(−5)to 10^(−1)M,respectively,which is the highest SI when compared to ever reported for Ca^(2+)and NH_(4)^(+)ion-sensitive transistors.This work introduces a general approach for ultrahigh sensitivity and wide detection range IS-OECTs,and could be extended to other transistor-based biomolecule and ion sensors,offering valuable insights for advancing high-performance bioelectronics.
基金supported by the National Key Research and Development Program of China(2021YFB2400400)the National Natural Science Foundation of China(Key Project,52131306)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515040011)the Project on Carbon Emission Peak and Neutrality of Jiangsu Province(BE2022031-4)the Fundamental Research Funds for the Central Universities(2242023R10001 and 2242024K30047)。
文摘Aqueous zinc-ion batteries have emerged as promising candidates for large-scale energy storage.Despite its potential as a cathode material for AZIBs,H_(2)V_(3)O_(8) suffers from poor electrical conductivity,vanadium dissolution,and structural instability,which severely compromises its rate performance and cycling stability.To address these limitations,we have developed a polypyrrole-coated H_(2)V_(3)O_(8) composite(H_(2)V_(3)O_(8)@Ppy).Density functional theory calculations demonstrate that Ppy exhibits substantially stronger interactions with HVO_(3)(−1.97 eV)compared to hydrated Zn^(2+) ions(−0.205 eV).This selective interaction enables the Ppy coating to effectively capture dissolved HVO_(3) species while maintaining efficient transport of solvated Zn2+ion clusters,thereby preventing structural degradation of the cathode.The optimized H_(2)V_(3)O_(8)@Ppy cathode delivers an impressive initial capacity of 405 mA h g^(-1) at 100 mA g^(-1) and demonstrates exceptional cycling stability,maintaining nearly 100%capacity retention after 800 cycles at 2 A g^(−1).Furthermore,a quasisolid-state zinc-ion battery incorporating H_(2)V_(3)O_(8)@Ppy cathode exhibits excellent mechanical flexibility and superior longterm cycling performance.Notably,in situ XRD analysis reveals for the first time a two-step phase transformation mechanism of H_(2)V_(3)O_(8) during discharge/charge processes.This study presents an effective strategy for enhancing the structural stability of H_(2)V_(3)O_(8) cathodes in aqueous zinc-ion batteries.
基金supported by the Chinese Academy of Sciences(No.KZCX2-YW-410)the National Natural Science Foundation of China(No.40776058)+1 种基金the National 863 High Technology Project of the Ministry of Science and Technology of China(No.2007AA09Z103)the Outstanding Youth Natural Science Foundation of Shandong Province(No.JQ200814)
文摘Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho...
基金financially supported by the Chinese Academy of Sciences(No.KZCX2-YW-410)the National Natural Science Foundation of China(Nos.40776058 and 20977073)+2 种基金the National 863 High Technology Project of the Ministry of Science and Technology of China(No.2007AA09Z103)the Outstanding Youth Natural Science Foundation of Shandong Province(No.JQ200814)the Taishan Scholar Program of Shandong Province
文摘A novel potentiometric detection strategy based on functionalized magnetic nanoparticles has been developed for rapid and sensitive sensing of polyions.Highly dispersed magnetic nanoparticles coated with ion exchanger and plasticizer could promote an in situ cooperative ion-pairing interaction between the ion exchanger and the polyion analyte in sample solution by dramatically reducing the mass-transfer distance.With applying a magnetic field,the nanoparticles can be attached to the surface of ion exchanger free polymeric membrane.The observed potential signals are related to the polyion concentrations.The proposed polymeric membrane electrode exhibits a linear relationship between the greatest potential response slope（dE/dt） and the logarithm of protamine concentration in the range of 0.05-5μg/mL with a lower detection limit of 0.033μg/mL.
文摘15-day old seedlings of wheat and rape were grown in a series of solutions with different concentrations of KNO3 for a definite period of time. The changes in NO3- concentration of the solutions were determined by the double ion-selective electrode method, and then the amount of NO3- taken up by the plants was estimated and values of Km and Imax of the Michealis-Menten equation were calculated. Results show that both the method and conditions of determination affected the values of Km and Imax. For example, the Km value was appreciably reduced when the volume of culture solution was increased or when the duration of nutrient uptake was shortened; the Km value obtained with short-term depletion method was higher than that obtained with long-term one. Similar Variations were found for the values of Imax. There was a considerable difference in the characteristics of uptake kinetics between wheat and rape when determined under the same conditions of determination. The isotherm of NO3- uptake by wheat could be separated into saturated and unsaturated parts, and when the concentration of NO3- exceeded 180 uuuuuuuuuuuuM, the relationship between the rate of NO3- uptake and NO3- concentration tended to be linear. However, the isotherm of NO3- uptake by rape was found to fit the Michealis-Menten equation and no linear relationship could be found.
文摘Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.
基金Project supported by the National Natural Science Foundation of China.
文摘The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% of adsorption on all the samples occurred during the first 5 minutes.All adsorption time-dependent data could fit the surface second-order equation very well.The values of Xm were goethite>kaolinite,and latosol>red soil at the same initial reaction concentration.The values of k were kaolinite>>goethite,and latosol>red soil at the same reaction pH and initial concentration.The higher the suspension pH,the faster the adsorption occurred.The meaning of Xm got by the two ion-selective electrode technique(one kind of batch technique) was different from that by the miscible displacement technique in that the former was only the equilibrium adsorption amount at a definite concentration and pH,but the latter was almost equal to the adsorption capacity at a definite pH with much less influence of concentration.One Pb^2+ was supposed to occupy two adsorption sites as the adsorption mechanism is concerned.
基金supported by the National Natural Science Foundation of China (21675029, 21665009, 21475025)the Key Joint Project for Health Education of Fujian Province (WKJ2016-2-15)the Program for Changjiang Scholars and Innovative Research Team in University (IRT15R11)
文摘An ion-selective electrode(ISE)-based immunoassay has been innovatively designed for the sensitive detection of liver cancer biomarker(alpha-fetoprotein,AFP),using metal sulfide quantum dot(QD)-based nano labels.Cd S QDs-aggregated PAMAM dendrimer(QD-DE)was first synthesized and functionalized with polyclonal rabbit anti-human AFP antibodies.Thereafter,a sandwich immunoreaction was implemented on monoclonal mouse anti-human AFP antibody-coated microplate by using antibody-functionalized QD-DE as the secondary antibody.Accompanying the immunocomplex,subsequent potentiometric detection of cadmium ion dissolved from the QD-DE under acidic condition was conducted on a portable cadmium ion-selective electrode(Cd-ISE).Results revealed that the electrode potential of the Cd-ISE increased with the increment of AFP concentration from 0.1 to 100 ng m L^(-1)at a detection limit(LOD)of 68 pg m L^(-1).The relative standard deviations(RSD)were below9.09%and 10.54%for the intra-and inter-assay,respectively.Additionally,six human serum specimens were determined on CdISE-based immunosensor by using commercial human AFP ELISA kit as the reference,and gave good relationship between two methods.Importantly,Cd-ISE-based immunoassay offers the promise for simple and cost-effective screening of disease-related biomarkers.
