An all-solid-state ion-selective electrode(ISE)for the detection of potassium ions in complex media was developed based on functional peptides with both antibacterial and antifouling properties.While exhibiting unique...An all-solid-state ion-selective electrode(ISE)for the detection of potassium ions in complex media was developed based on functional peptides with both antibacterial and antifouling properties.While exhibiting unique antifouling property,the ISE capitalized on the high surface area of the conductive metalorganic framework(MOF)solid transducer layer to facilitate rapid ion-electron transfer,consequently improving the electrode stability.For a short period,the application of a±1 n A current to the ISE resulted in a slight potential drift of 2.5μV/s,while for a long-term stability test,the ISE maintained a stable Nernstian response slope over 8 days.The antifouling and antibacterial peptide effectively eradicated bacteria from the electrode surface while inhibited the adhesion of bacteria and other biological organisms.Both theoretical calculations and experimental results indicated that the incorporation of peptides in the sensing membrane did not compromise the detection performance of the ISE.The prepared antifouling potassium ion-selective electrode exhibited a Nernstian response range spanning from 1.0×10^(–8)mol/L to 1.0×10–3mol/L,with a detection limit of 2.51 nmol/L.Crucially,the prepared solid-contact ISE maintained excellent antifouling and sensing capabilities in actual seawater and human urine,indicating a promising feasibility of this strategy for constructing ISEs suitable for practical application in complex systems.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
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 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 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
Three new 'tailed' porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ...Three new 'tailed' porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new 'tailed' porphyrins toward SCN- have been studied.展开更多
Robust and easy-to-handle solid-contact ion-selective electrodes (SC-ISEs) based on graphite paste have been developed for the potentiometric detection of NO-3 and NH+4 in environmental samples. Polypyrrole (PPy) has ...Robust and easy-to-handle solid-contact ion-selective electrodes (SC-ISEs) based on graphite paste have been developed for the potentiometric detection of NO-3 and NH+4 in environmental samples. Polypyrrole (PPy) has been used as intermediate layer and solid contact between the electron-conducting graphite paste substrate and the ion-conducting polyvinylchloride (PVC)-containing membrane with the immobilized ionophore. For the nitrate- and ammonium-selective electrodes, tridodecylmethylammonium nitrate (TDMA-NO3) and nonactin have been used as ion-complexing compounds, respectively. Both ISEs show nearly Nernstian response in the linear range from 10-5 mol/L to 10-1 mol/L with average slopes of >58 mV/decade. The ISEs possess short response times (<20 s).展开更多
A new ion-selective pH electrode of PVC membrane used formeasuring pH of the upper digestive tract is reported in this paper, which wasprepared with tri-n-octylamine or tris-(2-ehtylhexy)amine sensitive materials,and ...A new ion-selective pH electrode of PVC membrane used formeasuring pH of the upper digestive tract is reported in this paper, which wasprepared with tri-n-octylamine or tris-(2-ehtylhexy)amine sensitive materials,and polyvinylchloride (PVC) as a base. It was shown that the electrode has widelinearity (0.5-8, 3-12), good reproducibility, proper responsible time (【30s),longer life span (15 days). And the measurement was carried out in 50 cases bythe electrode.展开更多
The authors developed a nitrate ion-selective electrode（ISE） based on poly（vinyl chloride）（PVC） membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nit...The authors developed a nitrate ion-selective electrode（ISE） based on poly（vinyl chloride）（PVC） membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nitrate-sensitive membranes was optimized by tuning the composition of components.The electrode exhibits a linear response with a Nernstian slope of（52±1.0） mV per decade for the nitrate ion concentration ranging from 5.8×10-5 mol/L to 1.0 mol/L.The electrode can be used to detect a low concentration of nitrate ions down to 3×10-5 mol/L in a pH range of 2.1―11.5 without any compensation.The advantage of the electrode includes simple preparation,short response time and good repeatability.The detection performance of the novel electrode on nitrate ions has been tested for water samples.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
A comparative study was conducted using two designs of a roxatidine acetate （ROX）-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. ...A comparative study was conducted using two designs of a roxatidine acetate （ROX）-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. The fabrication of electrodes was based on roxatidine-tetraphenylborate （ROX-TPB） as an ion-association complex in a PVC matrix using different plasticizers. Electrode A has a linear dynamic range of 2.2 ×10^-5 mol/L to 1.0 ×10^-2 mol/L, with a Nernstian slope of 54.7 mV/decade and a detection limit of 1.4 ×10^-6 mol/L. Electrode B shows linearity over the concentration range of 1.0×10^-6 mol/L to 1.0×10^-2 tool/L, with a Nernstian slope of 51.2 mV/decade and a limit of detection of 1.1×10^7 mol/L which is remarkably improved as a result of diminishing ion fluxes in this solid contact, ion-selective electrode. The proposed sensors display useful analytical characteristics for the determination of ROX in bulk powder and its pharmaceutical formulation. The present electrodes show clear discrimination of ROX from several inorganic, organic ions, sugars, some common drug excipients and the degradation product （3-[3-（1-piperidinyl methyl） phenoxy] propyl amine） of ROX. Furthermore, the proposed electrodes were utilized for the determination of ROX in human plasma, where electrode B covers drug Cmax which indicated its applicability to pharmacokinetic, bioavailability and bioequivalent studies. The results obtained by the proposed electrodes were statistically analyzed and compared with those obtained by a reported HPLC method. No significant difference for either accuracy or precision was observed.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
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
Solid oxide cells(SOCs)are emerging devices for efficient energy storage and conversion.However,during SOC operation,gaseous chromium(Cr)species released from Fe-Cr alloy interconnect can lead to Cr deposition and poi...Solid oxide cells(SOCs)are emerging devices for efficient energy storage and conversion.However,during SOC operation,gaseous chromium(Cr)species released from Fe-Cr alloy interconnect can lead to Cr deposition and poisoning of air electrodes,causing substantial degradation in electrochemical performance and compromising the longterm stability of SOCs.This mini-review examines the mechanism of Cr deposition and poisoning in air electrodes under both fuel-cell and electrolysis modes.Furthermore,emphasis is placed on the recent advancements in strategies to mitigate Cr poisoning,offering insights into the rational design and development of active and Cr-tolerant air electrodes for SOCs.展开更多
Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage p...Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.展开更多
The analytical performance of H+-selective solid-contact ion-selective electrodes(SCISEs)based on solid contact polyaniline doped with chloride(PANI(Cl))and poly(3,4-ethylenedioxythiophene)doped with poly(styrene sulf...The analytical performance of H+-selective solid-contact ion-selective electrodes(SCISEs)based on solid contact polyaniline doped with chloride(PANI(Cl))and poly(3,4-ethylenedioxythiophene)doped with poly(styrene sulfonate)(PEDOT(PSS))was characterized by a developed coulometric signal transduction method.PEDOT(PSS)solid contact is covered by PVC based H+-selective membrane.The obtained coulometric signal demonstrates that the cumulated charge can be amplified by increasing the capacitance of solid contact.SCISEs covered with spin-coated membrane behave faster amperometric response than electrodes with drop-cast mem-brane.In contrast to earlier works,the amperometric response and impedance spectrum demonstrates H+transfer through SCISEs is independent from the thickness of membrane.The exceptional behavior of PANI(Cl)H+-SCISEs shows that the capacitance estimated from impedance spectrum at low frequency 10 mHz and coulometric signal of PANI(Cl)based SCISEs is influenced by the applied po-tentials,whereas PEDOT(PSS)solid contact is independent from the chosen applied potentials.Furthermore,preliminary investiga-tions of coulometric signal transduction on flexible pH sensor implies its potential applications in wearable sensors for sweat ion concentration detection.展开更多
Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-calixarene (3) and 25,27-dihydroxy-26,28-bis(3-phenylthia-propoxy)-5,11,17,23-tetra-tert-butylcalixarene (4) were synthesized for the evaluation of their ion-...Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-calixarene (3) and 25,27-dihydroxy-26,28-bis(3-phenylthia-propoxy)-5,11,17,23-tetra-tert-butylcalixarene (4) were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes (ISEs). ISEs based on 3 and 4 as neutral ionophores were prepared, and their selectivity coefficients for Ag + (lg K pot Ag,M) were investigated against other alkali metal, alkaline-earth metal, aluminum, thallium (I), lead and some transition metal ions using the separate solution method (SSM). These ISEs showed excellent Ag + selectivity over most of the interfering cations examined, except for Hg 2+ and Fe 2+ having relative smaller interference (lg K pot Ag,M≤-2.1).展开更多
Ion-selective electrode(ISE)is a quick and low-cost method of soil nitrate nitrogen(N)detection.The measurement models of soil nitrate-N based on ISEs includes the linear regression model,multiple linear regression mo...Ion-selective electrode(ISE)is a quick and low-cost method of soil nitrate nitrogen(N)detection.The measurement models of soil nitrate-N based on ISEs includes the linear regression model,multiple linear regression model and BP neural network model,and so on.Three models were analyzed in theory,measurement experiments of validation samples and soil nitrate-N concentrations were carried out in this study,and the measurement accuracies of the three models were compared.The results showed that,in the measurement experiments of validation samples and soil nitrate-N concentrations,BP neural network model had the highest accuracy(the average relative errors between results of the BP neural network model and the reference values were 5.07%and 8.81%,respectively)among the three models,multiple linear regression model had the second highest accuracy(the average relative errors between results of the multiple linear regression model and the reference values were 7.70%and 10.51%,respectively),linear regression model couldn’t exclude the interference of chloride ions so that it had the lowest accuracy(the average relative errors between results of the linear regression model and the reference values were 11.16%and 12.28%,respectively)among the three models.The BP neural network model can effectively restrain the interference of chloride ions,and it has a high accuracy for the measurement of soil nitrate-N concentration,so that the BP neural network model can be used to measure soil nitrate-N concentration accurately.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22174082,22374085)the Key Research and Development Program of Shandong Province(No.2021ZDSYS30)Qingdao Postdoctoral Innovation Project Funding(No.QDBSH20220201038)。
文摘An all-solid-state ion-selective electrode(ISE)for the detection of potassium ions in complex media was developed based on functional peptides with both antibacterial and antifouling properties.While exhibiting unique antifouling property,the ISE capitalized on the high surface area of the conductive metalorganic framework(MOF)solid transducer layer to facilitate rapid ion-electron transfer,consequently improving the electrode stability.For a short period,the application of a±1 n A current to the ISE resulted in a slight potential drift of 2.5μV/s,while for a long-term stability test,the ISE maintained a stable Nernstian response slope over 8 days.The antifouling and antibacterial peptide effectively eradicated bacteria from the electrode surface while inhibited the adhesion of bacteria and other biological organisms.Both theoretical calculations and experimental results indicated that the incorporation of peptides in the sensing membrane did not compromise the detection performance of the ISE.The prepared antifouling potassium ion-selective electrode exhibited a Nernstian response range spanning from 1.0×10^(–8)mol/L to 1.0×10–3mol/L,with a detection limit of 2.51 nmol/L.Crucially,the prepared solid-contact ISE maintained excellent antifouling and sensing capabilities in actual seawater and human urine,indicating a promising feasibility of this strategy for constructing ISEs suitable for practical application in complex systems.
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.
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 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.
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Three new 'tailed' porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new 'tailed' porphyrins toward SCN- have been studied.
文摘Robust and easy-to-handle solid-contact ion-selective electrodes (SC-ISEs) based on graphite paste have been developed for the potentiometric detection of NO-3 and NH+4 in environmental samples. Polypyrrole (PPy) has been used as intermediate layer and solid contact between the electron-conducting graphite paste substrate and the ion-conducting polyvinylchloride (PVC)-containing membrane with the immobilized ionophore. For the nitrate- and ammonium-selective electrodes, tridodecylmethylammonium nitrate (TDMA-NO3) and nonactin have been used as ion-complexing compounds, respectively. Both ISEs show nearly Nernstian response in the linear range from 10-5 mol/L to 10-1 mol/L with average slopes of >58 mV/decade. The ISEs possess short response times (<20 s).
文摘A new ion-selective pH electrode of PVC membrane used formeasuring pH of the upper digestive tract is reported in this paper, which wasprepared with tri-n-octylamine or tris-(2-ehtylhexy)amine sensitive materials,and polyvinylchloride (PVC) as a base. It was shown that the electrode has widelinearity (0.5-8, 3-12), good reproducibility, proper responsible time (【30s),longer life span (15 days). And the measurement was carried out in 50 cases bythe electrode.
基金Supported by the Project of Wuxi Pollution Prevention Funding Agency,China(No.2008-1)
文摘The authors developed a nitrate ion-selective electrode（ISE） based on poly（vinyl chloride）（PVC） membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nitrate-sensitive membranes was optimized by tuning the composition of components.The electrode exhibits a linear response with a Nernstian slope of（52±1.0） mV per decade for the nitrate ion concentration ranging from 5.8×10-5 mol/L to 1.0 mol/L.The electrode can be used to detect a low concentration of nitrate ions down to 3×10-5 mol/L in a pH range of 2.1―11.5 without any compensation.The advantage of the electrode includes simple preparation,short response time and good repeatability.The detection performance of the novel electrode on nitrate ions has been tested for water samples.
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.
文摘A comparative study was conducted using two designs of a roxatidine acetate （ROX）-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. The fabrication of electrodes was based on roxatidine-tetraphenylborate （ROX-TPB） as an ion-association complex in a PVC matrix using different plasticizers. Electrode A has a linear dynamic range of 2.2 ×10^-5 mol/L to 1.0 ×10^-2 mol/L, with a Nernstian slope of 54.7 mV/decade and a detection limit of 1.4 ×10^-6 mol/L. Electrode B shows linearity over the concentration range of 1.0×10^-6 mol/L to 1.0×10^-2 tool/L, with a Nernstian slope of 51.2 mV/decade and a limit of detection of 1.1×10^7 mol/L which is remarkably improved as a result of diminishing ion fluxes in this solid contact, ion-selective electrode. The proposed sensors display useful analytical characteristics for the determination of ROX in bulk powder and its pharmaceutical formulation. The present electrodes show clear discrimination of ROX from several inorganic, organic ions, sugars, some common drug excipients and the degradation product （3-[3-（1-piperidinyl methyl） phenoxy] propyl amine） of ROX. Furthermore, the proposed electrodes were utilized for the determination of ROX in human plasma, where electrode B covers drug Cmax which indicated its applicability to pharmacokinetic, bioavailability and bioequivalent studies. The results obtained by the proposed electrodes were statistically analyzed and compared with those obtained by a reported HPLC method. No significant difference for either accuracy or precision was observed.
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.
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.
基金supported by National Natural Science Foundation of China(22279018)National Natural Science Foundation of China(22005055)Natural Science Foundation of Fujian Province(2022J01085).
文摘Solid oxide cells(SOCs)are emerging devices for efficient energy storage and conversion.However,during SOC operation,gaseous chromium(Cr)species released from Fe-Cr alloy interconnect can lead to Cr deposition and poisoning of air electrodes,causing substantial degradation in electrochemical performance and compromising the longterm stability of SOCs.This mini-review examines the mechanism of Cr deposition and poisoning in air electrodes under both fuel-cell and electrolysis modes.Furthermore,emphasis is placed on the recent advancements in strategies to mitigate Cr poisoning,offering insights into the rational design and development of active and Cr-tolerant air electrodes for SOCs.
基金supported by Fundamental Research Funds for the Central Universities(2023KYJD1008)the Science Research Projects of the Anhui Higher Education Institutions of China(2022AH051582).
文摘Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.
基金We are grateful to the National Natural Science Foundation of China(22172040,21974031 and 22204026)the Project Funded by China Postdoctoral Science Foundation(2022M710859)+2 种基金the Department of Science and Techniques of Guangdong Province(2021A1515010180,2019B010933001)Guangzhou Municipal Science and Technology Bureau(202102010449)the Department of Guangdong Provincial Public Security(GZQC20-PZ11-FD084)fortheirfinancial support of thiswork.
文摘The analytical performance of H+-selective solid-contact ion-selective electrodes(SCISEs)based on solid contact polyaniline doped with chloride(PANI(Cl))and poly(3,4-ethylenedioxythiophene)doped with poly(styrene sulfonate)(PEDOT(PSS))was characterized by a developed coulometric signal transduction method.PEDOT(PSS)solid contact is covered by PVC based H+-selective membrane.The obtained coulometric signal demonstrates that the cumulated charge can be amplified by increasing the capacitance of solid contact.SCISEs covered with spin-coated membrane behave faster amperometric response than electrodes with drop-cast mem-brane.In contrast to earlier works,the amperometric response and impedance spectrum demonstrates H+transfer through SCISEs is independent from the thickness of membrane.The exceptional behavior of PANI(Cl)H+-SCISEs shows that the capacitance estimated from impedance spectrum at low frequency 10 mHz and coulometric signal of PANI(Cl)based SCISEs is influenced by the applied po-tentials,whereas PEDOT(PSS)solid contact is independent from the chosen applied potentials.Furthermore,preliminary investiga-tions of coulometric signal transduction on flexible pH sensor implies its potential applications in wearable sensors for sweat ion concentration detection.
文摘Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-calixarene (3) and 25,27-dihydroxy-26,28-bis(3-phenylthia-propoxy)-5,11,17,23-tetra-tert-butylcalixarene (4) were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes (ISEs). ISEs based on 3 and 4 as neutral ionophores were prepared, and their selectivity coefficients for Ag + (lg K pot Ag,M) were investigated against other alkali metal, alkaline-earth metal, aluminum, thallium (I), lead and some transition metal ions using the separate solution method (SSM). These ISEs showed excellent Ag + selectivity over most of the interfering cations examined, except for Hg 2+ and Fe 2+ having relative smaller interference (lg K pot Ag,M≤-2.1).
基金The research was supported by the key project of the National Natural Science Foundation of China(61134011).
文摘Ion-selective electrode(ISE)is a quick and low-cost method of soil nitrate nitrogen(N)detection.The measurement models of soil nitrate-N based on ISEs includes the linear regression model,multiple linear regression model and BP neural network model,and so on.Three models were analyzed in theory,measurement experiments of validation samples and soil nitrate-N concentrations were carried out in this study,and the measurement accuracies of the three models were compared.The results showed that,in the measurement experiments of validation samples and soil nitrate-N concentrations,BP neural network model had the highest accuracy(the average relative errors between results of the BP neural network model and the reference values were 5.07%and 8.81%,respectively)among the three models,multiple linear regression model had the second highest accuracy(the average relative errors between results of the multiple linear regression model and the reference values were 7.70%and 10.51%,respectively),linear regression model couldn’t exclude the interference of chloride ions so that it had the lowest accuracy(the average relative errors between results of the linear regression model and the reference values were 11.16%and 12.28%,respectively)among the three models.The BP neural network model can effectively restrain the interference of chloride ions,and it has a high accuracy for the measurement of soil nitrate-N concentration,so that the BP neural network model can be used to measure soil nitrate-N concentration accurately.
