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Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration 被引量:2
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作者 Jing Ke Hanfei Dou +3 位作者 Ximin Zhang Dushimabararezi Serge Uhagaze Xiali Ding Yuming Dong 《Journal of Pharmaceutical Analysis》 SCIE CAS 2016年第6期404-409,共6页
As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in thi... As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments. 展开更多
关键词 Dissociation CONSTANTS ALENDRONATE SODIUM Distribution curve Piecewise linear regression ACID-BASE potentiometric TITRATION
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POTENTIOMETRIC TITRATION OF CALCIUM IN SEAWATER 被引量:1
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作者 谢式南 纪红 +1 位作者 吴爱琴 陈国华 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1997年第1期32-35,共4页
By using calcium ion selective elatrode (Ca ISE) as indicating electrode, saturated calomel electrode (SCE) as reference electrode and EGTA as titrant, calcium in seawater was determined by potentiometric titration in... By using calcium ion selective elatrode (Ca ISE) as indicating electrode, saturated calomel electrode (SCE) as reference electrode and EGTA as titrant, calcium in seawater was determined by potentiometric titration in borate buffer solution. This method can reduce observation errors in the determination of the endpoint, and thus provide better analytical precision(<0.08%) than present complexometric titration. 展开更多
关键词 CALCIUM ION SELECTIVE elatrode CALCIUM seawater potentiometric TITRATION
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Detection of Chlorides in Pore Water of Cement Based Materials by Potentiometric Sensors 被引量:1
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作者 Franc vegl Kurt Kalcher +2 位作者 Yi Jung Grosse-Eschedor Magda Balonis Andrzej Bobrowski 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期232-237,共6页
Free chloride ions dissolved in pore water of cement based materials initiate the corrosion of steel rebars used for reinforcement of concrete and thus pose serious constant danger to the safety of reinforced concrete... Free chloride ions dissolved in pore water of cement based materials initiate the corrosion of steel rebars used for reinforcement of concrete and thus pose serious constant danger to the safety of reinforced concrete structures.The in-situ monitoring of the content of chlorides in pore water with second order Ag/AgCl electrodes is an elegant approach which, however,suffers from poor stability of Ag/AgCl electrodes in highly alkaline environment like pore water.In this work the electrochemical stability of plain and stabilized electrodeposited Ag/AgCl sensors in extreme alkaline conditions are presented. The electrochemical processes were elucidated which govern the potentiometric response of Ag/AgCl sensors and determine their performance.The results have shown suitable stability and reproducibility of stabilized Ag/AgCl sensors over five months, which was sufficient for laboratory testing of chloride ingress into cement based materials.The embedded calibrated sensor elements were used to monitor the chloride uptake into cylindrical mortar specimen dipped into simulated pore water containing about 3 wt% of chloride ions.The velocity of diffusing front and the diffusion coefficient of chloride ions in pore water of cylindrical mortar sample were estimated from concentration-time profiles determined by chloride sensors positioned at defined positions in the sample wall. 展开更多
关键词 chloride sensor chloride ingress Ag/AgCl potentiometric detection reinforced concrete CORROSION durability.
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Acid Dissociation Constants of Functional Groups in Humic Substances:I.Affinity Spectrum Model Analysis of Potentiometric Data of Fulvic and Humic Acids Solutions from Weathered Coal and Dark Loessial Soil 被引量:1
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作者 DUJIN-ZHOU LUCHANG-QING 《Pedosphere》 SCIE CAS CSCD 1994年第3期201-208,共8页
Potentiometric experiments were carried out on the proton binding equilibria of FA extracted from a weathered coal and HA and Fa extracted from a dark loessial soil.The affinity spectrum model was employed to treat th... Potentiometric experiments were carried out on the proton binding equilibria of FA extracted from a weathered coal and HA and Fa extracted from a dark loessial soil.The affinity spectrum model was employed to treat the experimental data.The affinity spectrum model technique could“magnify” the heterogeneity of the proton binding equilibria.so it was useful for comparing and studying the characteristics of humic substances with similar properties.According to the affinity spectra,we also found that the direction of the titration could affect the properties of the equilibria of FA from the weathered coal,and the acidic functional groups contained in FA from the weathered coal were larger in quantity than those contained in HA and FA from the dark loessial soil. 展开更多
关键词 affinity spectrum HETEROGENEITY humic substances potentiometric titration
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Determination of Formation Constants of Co ̄(2+), Ni ̄(2+),Cu ̄(2+) and Zn ̄(2+) Complexes with Humic and Fulvic Acidsby Potentiometric Titration Method 被引量:1
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作者 DUJIN-ZHOU LUCHANG-QING 《Pedosphere》 SCIE CAS CSCD 1994年第4期289-296,共8页
The formation constants of Co ̄(2+), Ni ̄(2+), Cu ̄(2+) and Zn ̄(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof... The formation constants of Co ̄(2+), Ni ̄(2+), Cu ̄(2+) and Zn ̄(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof composition of the complexation solutions were obtained by two graphical approaches respectively Theformation constants decreased with increasing concentration of metal in the solution. The results provideunambiguous evidence for the heterogeneity of the function groups of humic substances. The formationconstants of FA were much smaller than those of HA, and the formation constants of Cu ̄(2+) were muchgreater than those of Co ̄(2+) , Ni ̄(2+) and Zn ̄(2+) . The potentiometric titration method for determining formationconstants are also discussed in the article. 展开更多
关键词 formation constants of complexes humic and fulvic acids potentiometric titration red soil
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A NOVEL BITTER DETECTION BIOSENSOR BASED ON LIGHT ADDRESSABLE POTENTIOMETRIC SENSOR 被引量:1
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作者 CHUNSHENG WU LIPING DU +1 位作者 LIHUI MAO PING WANG 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2012年第2期34-40,共7页
This paper presents a novel biosensor for bitter substance detection on the basis of light addressable potentiometric sensor(LAPS).Taste receptor cells(TRCs)were used as sensitive elements,which can respond to differe... This paper presents a novel biosensor for bitter substance detection on the basis of light addressable potentiometric sensor(LAPS).Taste receptor cells(TRCs)were used as sensitive elements,which can respond to different bitter stimuli with extreme high sensitivity and speci-ficity.TRCs were isolated from the taste buds of rats and cultured on the surface of LAPS chip.Due to the unique advantages such as single-cell recording,light addressable capability,and noninvasiveness,LAPS chip was used as secondary transducer to monitor the responses of TRCs by recording extracelluar potential changes.The results indicate LAPS chip can effectively record the responses of TRCs to different bitter substances used in this study in a real-time manner for a long-term.In addition,by performing principal component analysis on the LAPS recording data,different bitter substances tested can be successfully discriminated.It is suggested this TRCsLAPS hybrid biosensor could be a valuable tool for bitter substance detection.With further improvement and novel design,it has great potentials to be applied in both basic research and practical applications related to bitter taste detection. 展开更多
关键词 Taste receptor cells bitter detection bitter signal transduction light addressable potentiometric sensor BIOSENSOR
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Determination of Sulfides in FCC Gasoline by Using the Potentiometric Titration of Lead Tetraacetate
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作者 罗立文 夏道宏 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第3期448-450,共3页
Compared with conventional method of violet spectrum, determination of the content of sulfides in fluid catalytic cracking (FCC) gasoline by using the potentiometric titration of lead tetraacetate has some advantages ... Compared with conventional method of violet spectrum, determination of the content of sulfides in fluid catalytic cracking (FCC) gasoline by using the potentiometric titration of lead tetraacetate has some advantages such as clear potentiometric abrupt change at the stoichiometric point, stable potentiometric value, exact and credible results, and simple operation. The content of sulfides in FCC gasoline of Shenghua refinery is 0.136% by this method. The standard deviation about this method is less than 0.01% and the relative standard deviation is less than 2.42%. 展开更多
关键词 SULFIDE GASOLINE lead tetraacetate potentiometric titration
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Neurochip Based on Light-addressable Potentiometric Sensor
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作者 Qingjun Liu Hua Cai +3 位作者 Ying Xu Lifeng Qin Lijiang Wang Ping Wang 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期413-416,共4页
<正>A novel neurochip based on light addressable potentiometric sensor (LAPS) is designed.Using its light addressable characteristic.The problems of the limitations of restricted discrete active sites of current... <正>A novel neurochip based on light addressable potentiometric sensor (LAPS) is designed.Using its light addressable characteristic.The problems of the limitations of restricted discrete active sites of current neurochips,such as microelectrode array and field effect transistor array can be settled easily.Based on the theoretical analysis of the interface between cells and LAPS,spontaneously discharges of hippocampal neurons induced by Mg~ 2+)-free media treatment were recorded by LAPS.The results demonstrate that this kind of neurochip has potential to monitor electrophysiology of cultured cells in a non-invasive way. 展开更多
关键词 NEUROCHIP cell-based biosensor hippocampal neurons light-addressable potentiometric sensor
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THE SECOND RECIPROCAL DERIVATIVE POTENTIOMETRIC STRIPPING ANALYSIS
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作者 Xiang Yuan RUAN Ju Nan LI +3 位作者 Jian Cheng DENG Yi Hen LI Nan JIANG Yong Hong LONG 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第11期859-860,共2页
A theory of the second reciprocal derivative potentiometric stripping analysis with a mercury thin-film electrode is reported.
关键词 CD PB In SRD THE SECOND RECIPROCAL DERIVATIVE potentiometric STRIPPING ANALYSIS
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Studies on Determination of Ge in Au Alloys by Potassium Iodate Potentiometric Titration Method
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作者 ZHU Liya ZHOU Yu +8 位作者 TAN Yanshan LIU Wen LI Yong HAN Shouli TAN Wenjin HE Xiaotan WU Xilong XIE Hongchao CHEN Liangwei 《贵金属》 CAS CSCD 北大核心 2012年第A01期298-304,共7页
The paper presents a new method of determining Ge in gold alloys by potassium iodate potentiometric titration rather than by traditional distillation separation. The influences of conditions such as the reduction acid... The paper presents a new method of determining Ge in gold alloys by potassium iodate potentiometric titration rather than by traditional distillation separation. The influences of conditions such as the reduction acidity, dosage of sodium hypophosphite and reduction time on the determination of Ge were studied. Comparison was made between the influences of end-point indication for potential method and starch method on accruracy and precision of the analysed results, stability and sensitivity of end-point, selectivity of method and so on. The possibility of reaction in an electrochemical way was discussed. Ge in the alloys such as AuGe 12 , AuGeNi 12 2 , AuAgGe 18.8 12.5 and AuAgGeNi 43.8 6 0.2 was measured, respectively, with the relative standard deviation of 0.10%~0.31% and the recoveries of added standard Ge in sample of 99.40%~100.40% when the reduction acidity was 0.40~0.80 mol/L HCl and 3.3 mol/L H 3 PO 4, 15 g sodium hypophosphite and reduction time 40 min. The new method presented is high accuracy and precision in results, good stability and sensibility in end point, easy operation and strong selectivity of determination. When it is applied to analyse actual samples, satisfactory results are achieved. 展开更多
关键词 analytical chemistry GERMANIUM gold alloy potentiometric titration
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Enhanced Electrochemical and Physical Properties of Ag/AgCl Planar Reference Electrodesin Potentiometric Sensors by Graphite Oxide Layer
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作者 Tung Son Vinh Nguyen Tien Minh Huynh +1 位作者 Tin Chanh Duc Doan Chien Mau Dang 《材料科学与工程(中英文A版)》 2019年第2期83-90,共8页
The most common reference electrode (RE) which is used in electrochemical measurements is the Ag/AgCl electrode. In this study, we present a novel solid-state Ag/AgCl planar electrode that was coated with a thin layer... The most common reference electrode (RE) which is used in electrochemical measurements is the Ag/AgCl electrode. In this study, we present a novel solid-state Ag/AgCl planar electrode that was coated with a thin layer of Graphite Oxide (GO) as a protective layer. The Ag/AgCl planar electrode was fabricated by using the photolithography and lift-off method combined with the Ag[NH3]2Cl complex. The GO was produced by Hummer’s method and was deposited on top of the Ag/AgCl layer by drop-casting method. The layers of the fabricated reference electrode were characterized by micro Raman spectroscopy, Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The responding time of the planar electrode was short and the signal was more stable in comparison to the plainAg/AgCl electrode. The Open Circuit Potential (OCP) measurement with the fabricated electrode as the RE and the platinum electrode as the working electrode in electrolyte solutions which had various pH values was performed with a linear response in pH ranges from pH 5 to pH 8 and the linear correlation coefficient (R^2 = 0.9899). Moreover, the coating of the GO layers also enhanced the durability of the modified electrode. The results showed that the modified Ag/AgCl electrode with a thin layer GO as the protective layer could be used as plana REs for the potentiometric sensors. 展开更多
关键词 GRAPHITE OXIDE potentiometric sensor Ag/AgCl reference ELECTRODE
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All-Solid-State Screen-Printed Sensors for Potentiometric Calcium(II) Determinations in Environmental Samples
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作者 Johannes Schwarz Kathrin Trommer +1 位作者 Frank Gerlach Michael Mertig 《American Journal of Analytical Chemistry》 2018年第3期113-123,共11页
This paper describes preparation, characterization and electrochemical performance of novel planar miniaturized all-solid-state (ASS) screen-printed potentiometric sensors for the detection of Ca2+ ions in environment... This paper describes preparation, characterization and electrochemical performance of novel planar miniaturized all-solid-state (ASS) screen-printed potentiometric sensors for the detection of Ca2+ ions in environmental samples. Screen-printed graphite-based ion-selective electrodes (ISEs) and screen-printed reference electrodes based on silver-containing pastes have been applied in a space saving manner on common ceramic substrates with small dimensions. Applications to environmental samples are shown by direct potentiometry and potentiometric titrations in real water samples. Conducting polymers (CPs) have been used as solid-contact materials and as intermediate layer between the polyvinyl chloride (PVC)-containing ion-selective membrane and the graphite-containing substrate. Different diamides have been incorporated into the PVC membrane. In the range from 10-4 mol/L to 10-1 mol/L, the ISEs show linear slopes of 27 mV/decade, which is close to the Nernstian response. Moreover, the ISEs have response times of 6 months. The novel potentiometric ASS sensors enable simple and exact Ca2+ determinations in real samples. 展开更多
关键词 ALL-SOLID-STATE Sensor Ca2+-Selective Electrode potentiometric TITRATION Environmental SAMPLES
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The Electrode for Potentiometric Determinаtion of Chromium (III, VI) in Wаter Solutions
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作者 Shаmshiyа Аmerkhаnovа Dana Belgibayeva +1 位作者 Rustаm Shlyаpov Аitolkyn Uаli 《Journal of Materials Science and Chemical Engineering》 2014年第1期52-56,共5页
The possibility of determining of chromium (III, VI) ions was investigated in this paper. It is shown that the electrode on а basis of heаzlewoodite has high selectivity to chromium (III) ions. Also the stability co... The possibility of determining of chromium (III, VI) ions was investigated in this paper. It is shown that the electrode on а basis of heаzlewoodite has high selectivity to chromium (III) ions. Also the stability constants of complexes, forming in system “Cr3+-Mohr’s salt-Ca(OH)2-PVA ÷ PAA” were determined by potentiometric titration with ion-selective electrode. 展开更多
关键词 Heаzlewoodite CHROMIUM (III VI) IONS potentiometric Method
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Hydrolysis of Trivalent Holmium in Aqueous Solutions of 2 M Ionic Strength by Spectrophotometric and Potentiometric Methods
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作者 Miguel Angel Hernández-García Hilario López-González Alberto Rojas-Hernández 《Advances in Materials Physics and Chemistry》 2015年第5期161-170,共10页
The first hydrolysis constants of trivalent holmium in 2 M NaClO4 and 2 M NaCl at 303 K and in CO2 free conditions were determined. The pCH borderlines of precipitation and first hydrolysis were determined by means of... The first hydrolysis constants of trivalent holmium in 2 M NaClO4 and 2 M NaCl at 303 K and in CO2 free conditions were determined. The pCH borderlines of precipitation and first hydrolysis were determined by means of a spectrophotometric method and last one with the program SQUAD. Independently, the stability constant for the first hydrolytic species was determined, by means of potentiometric pH titrations whose data were treated with the program SUPERQUAD. The hydrolysis constants obtained were: ?and . These values attained by both methods are the same. The log10β1,Cl constants for the species HoCl2+ was also calculated for 2 M ionic strength and 303 K from the hydrolysis constant obtained in both perchlorate and chloride media. This value was logβ1,Cl = -0.56. 展开更多
关键词 HOLMIUM HYDROLYSIS SPECTROPHOTOMETRIC potentiometric Chloride of HOLMIUM Specie
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A Theoretical Model of pH-Based Potentiometric Biosensor Based on Immobilized Enzyme Membrane
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作者 Jeganathan Saranya Lakshmanan Rajendran Mariappan Uma Maheswari 《American Journal of Analytical Chemistry》 2016年第4期363-377,共15页
A theoretical model for the non steady-state response of a pH-based potentiometric biosensor immobilizing organophosphorus hydrolase (OPH) is discussed. The model is based on a system of five coupled nonlinear reactio... A theoretical model for the non steady-state response of a pH-based potentiometric biosensor immobilizing organophosphorus hydrolase (OPH) is discussed. The model is based on a system of five coupled nonlinear reaction-diffusion equations under non steady-state conditions for enzyme reactions occurring in potentiometric biosensor that describes the concentration of substrate and hydrolysis products within the membrane. New approximate analytical expressions for the concentration of the substrate (organophosphorus pesticides (OPs)) and products are derived for all values of Thiele modulus and buffer concentration using new approach of homotopy perturbation method. The analytical results are also compared with numerical ones and a good agreement is obtained. The obtained results are valid for the whole solution domain. 展开更多
关键词 Mathematical Modeling REACTION-DIFFUSION pH-Based potentiometric Biosensor Asymptotic Methods New Homotopy Perturbation Method
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Counterion Binding in Aqueous Solutions of Poly(vinylpyridines) as Assessed by Potentiometric Titration
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作者 Jim D. Roach Mandy M. Bondaruk +1 位作者 Abdulaziz Al-Abdulghani Zaid Shahrori 《Advances in Materials Physics and Chemistry》 2016年第9期249-261,共13页
The extent to which counterions bind to polyelectrolytes influences a variety of polymer-based applications, including polyelectrolyte enhanced ultrafiltration and forward osmosis using polyelectrolytes as draw agents... The extent to which counterions bind to polyelectrolytes influences a variety of polymer-based applications, including polyelectrolyte enhanced ultrafiltration and forward osmosis using polyelectrolytes as draw agents. Potentiometric titrations of poly (2-vinylpyridine) (P2VP), poly (3-vinylpyridine) (P3VP), and poly (4-vinylpydine) (P4VP) were performed using HBr, HCl, HNO<sub>3</sub>, and HClO<sub>4</sub> in both the presence and absence of added NaCl. Because of the systematic differences among the three polyelectrolytes, titration results provide insight into the role of polymer structure in the relative extents to which various counterions bind. Titration data reveal that ionization properties vary as functions of polymer investigated, titrant used, degree of protonation, and added salt concentration. Acid dissociation constants of the pyridinium moieties were found to generally increase with increasing degree of protonation, though appreciable differences were exhibited among the three polymers investigated. For all three polymers, Cl<sup>-</sup> demonstrated the lowest affinity for the charged pyridinium residues, while the affinities associated with Br<sup>-</sup> and NO<sup>-</sup>3</sub> were nearly identical to each other. The relative extent of binding for CIO<sup>-</sup>4</sub> varied across the polymers investigated, and was greatest for P4VP. 展开更多
关键词 Poly(vinylpyridine) Counterion Binding potentiometric Titration PERCHLORATE
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Sequential Injection Analysis of Ampicillin in Pharmaceuticals by Using Potentiometric Detectors Based on PVC and Sol-Gel Membranes
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作者 Nestor Zarate Alberto N.Araujo +1 位作者 M.Conceicao B.S.M.Montenegro Ricardo Perez-Olmos 《American Journal of Analytical Chemistry》 2011年第4期491-499,共9页
This work describes the construction and the evaluation of the general performance of new ampicilli-nate-selective electrodes based on manganese (III) tetraphenylporphyrin [Mn(III) TPP-Cl] as ionophore, incorporated i... This work describes the construction and the evaluation of the general performance of new ampicilli-nate-selective electrodes based on manganese (III) tetraphenylporphyrin [Mn(III) TPP-Cl] as ionophore, incorporated in both PVC and sol-gel membranes and directly applied onto a conductive graphite/epoxy resin support. The units were constructed without inner reference solution adopting conventional configuration and in the case of PVC membrane the tubular configuration was also adopted. The good working characteristics of these electrodes, made possible its application to the determination of ampicillin in pharmaceuticals formulations, both in conventional batch analysis and in flow conditions, when the electrodes were coupled to a SIA system. In the last case the potentiometric sensors presented linear response towards ampicillin concentration between 5.0 × 10–4 and 5.0 × 10–2 mol?l–1 with slopes of –57.4 and –63.5 mV?dec–1 for the PVC and sol-gel membranes, respectively. The developed procedures enable mean relative standard deviations better than 3% for all the samples analysed. The obtained results do not statistically differ from those furnished by applying the HPLC reference method. 展开更多
关键词 AMPICILLIN SIA potentiometric Detection Pharmaceutical Formulations
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A Potentiometric Evaluation of Stability Constants of Two-Step Overlapping Equilibria via a Bilogarithmic Hyperbolic Cosine Method
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作者 Samuel Beaumont Julia Martin Agustin G. Asuero 《Journal of Analytical Sciences, Methods and Instrumentation》 2016年第2期33-43,共11页
A bilogarithmic hyperbolic cosine method for the evaluation of overlapping formation constants at varying (or fixed) ionic strength is devised in this paper and applied to data reported in the analytical literature, i... A bilogarithmic hyperbolic cosine method for the evaluation of overlapping formation constants at varying (or fixed) ionic strength is devised in this paper and applied to data reported in the analytical literature, i.e. succinic acid system, Cu(II)-glycine system and Ag(I)-aminobutan-1-ol system. The method is based on the linearization of the formation function ? = f(pH) or ? = f(pL) data. A theoretical slope of unity should be obtained thus proving the correctness of the assumed equilibria. An additional advantage of the bilogarithmic method proposed is that it provides a closed scale representation of Y and X unlike other plots. This paper forms part of an investigation into the uses of bilogarithmic methods and hyperbolic functions in parameter estimation. Methods based on the application of spectrophotometric measurements have been the subject of recent studies. 展开更多
关键词 Formation Acidity Constants Overlapping Equilibria potentiometric Measurements Bilogarithmic Hyperbolic Cosine Method
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Highly sensitive potentiometric immunosensor for hepatitis B surface antigen diagnosis 被引量:2
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作者 YUAN Ruo TANG Dianping +4 位作者 CHAI Yaqin ZHANG Lingyan LIU Yan ZHONG Xia DAI Jianyuan 《Science China Chemistry》 SCIE EI CAS 2005年第1期49-57,共9页
A highly sensitive potentiometric immunosensor for the diagnoses of epidemic dis-eases has been developed by means of self-assembly to immobilize hepatitis B surface antibody(HBsAb)for the detection of hepatitis B sur... A highly sensitive potentiometric immunosensor for the diagnoses of epidemic dis-eases has been developed by means of self-assembly to immobilize hepatitis B surface antibody(HBsAb)for the detection of hepatitis B surface antigen(HBsAg)as a model.At first,the Nafion containing-SO^(-)_(3)groups was immobilized on a platinum electrode surface to absorb the-NH^(+)_(3)groups of antibody molecules via the opposite-charged adsorption technique,in the meantime,hepatitis B surface antibodies were adsorbed onto the surface of Au nanoparticles,then hepatitis B surface antibodies and Au nanopartilces were entrapped into polyvinyl butyral on the surface of Nafion film.The modified procedure was further characterized by electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).The influence and factors influencing the per-formance of resulting immunosensor were studied in detail.The resulting immunosensor exhib-ited sigmoid curve with log HBsAg concentrations,high sensitivity,wide linear range from 26 to 1280 ng·mL^(-1)with a detection limit of 3.1 ng·mL^(-1),rapid potentiometric response(<3 min)and long-term stability(>4 months).Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme-linked immunosorbent assays(ELISAs)method,implying a promising alternative approach for detecting HBsAg in the clinical diagnosis. 展开更多
关键词 NAFION polyvinyl butyral colloidal Au hepatitis B potentiometric immunosensor platinum electrode.
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Enzyme-loaded liposome with biocatalytic precipitation for potentiometric immunoassay of thyroid-stimulating hormone in thyroid carcinoma 被引量:1
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作者 Yongjin Cao Min Zheng +1 位作者 Weihua Cai Zongcai Wang 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第2期463-467,共5页
A simple and feasible potentiometric immunosensing platform based on enzymatic biocatalytic precipitation technique was designed for the sensitive detection of thyroid-stimulating hormone(TSH;a typical kind of biomark... A simple and feasible potentiometric immunosensing platform based on enzymatic biocatalytic precipitation technique was designed for the sensitive detection of thyroid-stimulating hormone(TSH;a typical kind of biomarkers for thyroid carcinoma),using horseradish peroxidase(HRP)-loaded liposome for the signal amplification.To construct such an assay system,a sandwich-type immunoreaction was readily carried out on monoclonal anti-TSH capture antibody-coated electrode by using polyclonal antiTSH secondary antibody-conjugated HRP-loaded liposome.Accompanying the formation of sandwichtype immunocomplex,the carried liposome was lysed through the added Triton X-100 to release the entrapped HRP molecules,which catalyzed the oxidation of 4-chloro-1-naphthol to produce an insoluble and uncharged organic precipitation on the electrode surface,thereby causing the change of the local electrical potential.Two labeling protocols with and without the liposome were investigated for detection of target TSH,improved analytical features were achieved with HRP-entrapped liposome.Under optimal conditions,the potentiometric immunosensor had good responses for TSH detection within the linear range of 0.01-30 p IU/mL at a detection limit of 0.0067 p IU/mL.Good reproducibility,high specificity and long-time stability were acquired during the assay procedure.Importantly,a wellmatched accuracy between the potentiometric immunosensor and commercial human TSH ELISA kit was gave for the analysis of human serum samples. 展开更多
关键词 POTENTIOMETER Modification electrode potentiometric IMMUNOASSAY Thyroid-stimulating hormone Enzyme-encapsulated LIPOSOME ENZYME biocatalytic PRECIPITATION
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