Complexometric titration of various metal cations by a potentiometric end point detection with metallic bismuth indicator electrode was studied. Bismuth electrode was prepared by electrodeposition of bismuth on a spiral wire platinum electrode from an aci...

Thiocyanate is first removed by precipitation with a small excess of a copper solution, and the cations are removed by passing the filtrate through a cation-exchange resin. The chloride is determined in the eluate by a potentiometric titration in which si...

The precipitation titration of alkali metal ions with tetraphenylborate was studied using the cationic sensitive glass electrode as the indicator electrode in the potentiometric measurements. As a result, a rapid direct method for the determination of the alkali metals was developed. The method has the advantage over existing ...

A sensitive potentiometric surfactant sensor based on a highly lipophilic 1,3-didecyl-2-methyl-imidazolium cation and a tetraphenylborate (TPB) antagonist ion was used as the end-point detector in ion-pair potentiometric surfactant titrations using sodium TPB as a titrant. Several analytical and technical grade ...

Comparison of experimental and theoretical potentiometric titrations of kaolinite at 25{degree}C indicates that the adsorption of H{sup +} and OH{sup {minus}} ions to the mineral surface are metal cation specific and that the net adsorption can be modeled in terms of the constituent oxide components. The authors conclude, from the ...

... determination in potentiometric titrations and fully automated generation of calibration curve data for multiple ion selective electrodes are described. ...

The extraction of alkali metal cations by the lipophilic, ionizable lariat ether bis-tert-octylbenzo- 14-crown-4-acetic acid (BOB14C4AA) dissolved in either o-xylene or 1-octanol was studied by two-phase potentiometric titration and ion-exchange chromatog...

The irradiation of a series of phenyl sulfonates and phosphates leads to the quantitative release of acidity with a reasonable quantum yield (?0.2). Products characterization, ion chromatography analysis and potentiometric titration are consistent with the intervening of two different paths in this reaction, viz. cationic with ...

... Title : Potentiometric Titration Method for Quantitative Determination of Hydrogen Peroxide. Descriptive Note : Patent application, Filed 11 Jul 2005. ...

) was investigated by means of potentiometric titrations and electrophoretic mobility. The titration curves-quantitatively. � 2006 Elsevier B.V. All rights reserved. Keywords: Latex; Polyelectrolyte; Potentiometric titration, no potentiometric ...

An electrochemical potentiometric titration method that entails titration of a known volume of a catholyte containing an unknown amount of hydrogen peroxide in a titration cell having two electrodes, a platinum working electrode and a silver/silver chlori...

... nitric acids. As method, volumetric analysis (titration) with potentiometric (electrochemical) indication was selected. For ...

When extraction reagents based on salts of quaternary ammonium bases (QAS) are used in the technology of purification of rare earth elements (REE), the problem arises of determining QAS in technological and dilute aqueous solutions (circulating waters and sewage). A direct method of determining cations of QAS is known, based on the use of ion-selective electrodes, reversible ...

A method was developed for the rapid determination of sulfate in the presence of ions such as uranyl and ferric, which interfere in most conventional methods. Sulfate was precipitated by the addition of excess barium acetate. The excess barium acetate was then determined by potentiometric titration with perchloric acid in an acetic acid medium. ...

Data published in the past 10 years on the use of ion-selective electrodes in direct potentiometry and potentiometric titration for the determination of organic medicinal drugs are analysed. In the vast majority of cases, ion-sensitive membranes contain associates of drug cations or anions with appropriate counter-ions. The theoretical ...

To determine cationic and nonionogenic surfactants in a mixture, the authors used potentiometric titration of aqueous solutions of the surfactants with 0.01M solution of tetraphenylborate. The indicator electrodes were polyvinyl chloride membrane electrodes with electroactive substances -- the cetylpyridinium salt of ...

A detailed exposition is given of the use of logarithmic diagrams and Gran plots to construct titration curves and to determine accurately the equivalence point in potentiometric complexometric titrations. PMID:18961242

The paper describes the determination of the stoichiometry of various inorganic compounds using automatic potentiometric EDTA titrations for 11 metals. It also describes stoichiometric determinations involving automatic redox titrations for chromium, sele...

A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctylphthalate in tetrahydrofuran. The reference was an Ag/AgCl single-junction electrode. The sensor was used in the following potentiometric titrations: (1) precipitation ...

The use of various types of graphite as indicator electrodes in potentiometry has been limited to acid-base and redox titrations. We have expanded the range of feasible titrations to: (1) precipitation titrations; (2) acid-base titrations; (3) compleximet...

The titration system utilizes the constant current coulometric titration of Goldbeck and Lerner. U(VI) is reduced to U(IV) by Fe(II). V(V) is generated to titrate the U(IV), and the titration is followed potentiometrically. The evaluation shows that the r...

During investigation of the effects of various cellulose films used in the construction of ion-selective electrodes (ISE) on the results from the determination of Ag(CN)/sub 2//sup -/ and Au(CN)/sub 2//sup -/ by precipitation potentiometric titration, it was established that the degree to which the cationic function of the ISE shows up ...

The complexation of alkaline-earth cations by different crown ethers, azacrown ethers, and cryptands has been studied in methanol solutions by means of calorimetric and potentiometric titrations. The smallest monocyclic ligands examined from 2:1 complexes (ratio of ligand to cation) with ...

Three coated wire electrodes (CWEs) for the antispasmodic drugs; dicyclomine (Dc), mebeverine (Mv) and drotaverine (Dv) hydrochlorides were developed. Each electrode based on ion-associate of a heteropoly anion with the drug cation incorporated in membrane sensor modified with graphite and deposited on silver internal solid contact. The influence of addition of graphite to the ...

The formation of 1:1- and 2:1-complexes of the crown ether 12C4 with mono- and bivalent cations was studied in methanol solutions by calorimetric, potentiometric and conductometric titrations. It is shown that not all donor atoms of the ligand 12C4 take part in complex formation. The accuracy of the three experimental methods are ...

The possibility of the use of simple potentiometric coated-wire sensors in the analysis of mixtures of ions, the determination of which is based on the ion-pairing principle, was studied. Attention was especially paid on the determination of thallium(I) in the presence of alkali metal ions, mercury(II), copper(II) and silver(I). It was found that thallium(I) can selectively be ...

Thallium(I) has been determined by potentiometric titration with sodium tetraphenylborate. The titrations were monitored with a double-junction reference electrode and various liquid-membrane and solid-state ion-selective electrodes. The largest end-point breaks were obtained with the liquid-membrane fluoroborate and nitrate ...

A potentiometric back-titration method for the determination of sulfate ions using a plasticized poly(vinyl chloride) membrane electrode sensitive to a titrant is described. The method is based on ion association between the excess of 2-aminoperimidinium added to the sulfate ion in the sample and sodium tetrakis (4-fluorophenyl) borate (FPB) in the ...

... A suitable probe cation is identified and luminescence titration curves for a variety of polyanions are presented. The luminescence ...

An analytical method based on automatic potentiometric EDTA and redox titrations was developed for the analysis of tellurides of lead and tin. First, the sum of lead and tin is titrated at pH 4.5 by adding a known excess of EDTA and back-titrating with a ...

Potentiometric titration behavior and the effects of dissolution on the titration experiment of a complex natural clay mineral, glauconite, were investigated and interpreted according to surface complexation theory. Considerable dissolution was detected in the time frame of the titration experiments, with the ...

We have evaluated the following new titrants for the potentiometric precipitation titration of perchlorate: cetyltrimethylammonium chloride (CETAC), cetyltrimethylammonium bromide (CETAB), cetylpyridinium chloride (CPC), and benzyldimethyltetradecylammoni...

While most laboratories use more and more expensive equipment for their analyses, this speaker insists on delaying progress by using ultrasimple equipment, available in any laboratory, to perform potentiometric titrations. While not all the data presented...

Upon request of the ESARDA working group 'Low enriched uranium conversion - and fuel fabrication plants' an interlaboratory comparison was organized, to assess the precision and accuracy concerning the determination of uranium by the potentiometric titrat...

A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctyphthalate in tetrahydrofuran. The reference electrode was an Ag/AgCl single-junction electrode. The sensor was us...

A potentiometric titration method for determinig high-equivalent-weight sulfonates has been developed. This method utilizes a precipitation reaction between sulfonate and quaternary ammonium ions. A PVC (polyvinyl chloride) membrane electrode, which respo...

A potentiometric method was devised for determining chlorine bound to boron in organoboron compounds. The hydrochloric acid formed through esterification of the chlorine bound to boron was titrated potentiometrically with standard silver nitrate. (auth)

... 7 served as a benchmark energy soutce for undersea ... 11 of a color change by a human operator. ... as the titrant is added the potential between ...

... Mixtures of catechol, glycine, phthalic acid and salicylic acid were used to simulate potentiometric and complexometric titrations. ...

Calorimetric and potentiometric titrations have been used to evaluate direct and indirect methods of analysis for the carboxyl content of aquatic humic substances. The effects of cation binding, base strength, and removal of humic reaction products on carboxyl content values have been examined. The results suggest that the most ...

analysis and non-aqueous potentiometric titration data.. Changes in the molecular mass of the asphalt analysis and non-aqueous potentiometric titration data. Oxidative aging in the presence of water promoted spectroscopy analysis and non-aqueous potentiometric titration ...

Potentiometric titration of the zwitter-ion of 7-aminoacetoxycephalosporanic acid (7-ACA) was performed and the constants of its ionization were estimated. The minimum solubility of the 7-ACA zwitter-ion (20 degrees C, 0.1 M NaCl) was determined and the solubility curve of 7-ACA at wide pH ranges was calculated. Equilibrium of the ...

Stability constants and thermodynamic values for the complex formation of alkali ions by crown ethers, diaza crown ethers and cryptands have been measured by means of potentiometric and calorimetric titrations in acetone as solvent. The interactions between the ligands and solvent molecules play an important role for the complex formation. Cryptands form ...

The objective of this research program is to elucidate the chemical principles which are responsible for the cation selectivity and permeability of liquid membranes containing macrocyclic carriers. Several new macrocyclic carriers were synthesized during the last three year period. In addition, new, more convenient synthetic routes were achieved for several nitrogen-containing ...

Boron in PWR primary coolant and related waters may be determined as boric acid by titration with sodium hydroxide, using a glass electrode as a pH indicator. With a modern automatic titrator, the analysis is quick, convenient, accurate and precise. In th...

An improved method is presented for determining the equivalence point in potentiometric titrations. Titration rate and data acquisition are under computer control, and ion-selective electrodes are used as indicators. As the titration proceeds, the potentiometric curve and Gran (antilog) plot ...

The objective of our research program is to elucidate the chemical principles which are responsible for the cation selectivity and permeability of liquid membranes containing macrocyclic carriers. Several new macrocyclic carriers were synthesized during the last three year period, including selenium-containing macrocycles, new crown-4 structures, and several new crown ...

The objective of our research program is to elucidate the chemical principles which are responsible for the cation selectivity and permeability of liquid membranes containing macrocyclic carriers. Several new macrocyclic carriers were synthesized during the last three year period, including selenium-containing macrocycles, new crown-4 structures, and several new crown ...

Potentiometric titration curves of carboxyl-containing polyacrylic cation exchangers (Amberlite IRC 86, Dowex MAC 3, Lewatit CNP 80, Purolite C 104, and Relite CNS) in the H form with calcium ions were measured. It was found that the apparent equilibrium constant strongly depended on the composition of resinate solutions, which was ...

Preparation, characterization, and applications of a 1,10-phenanthrolinium cation (phenH(+))-sensitive potentiometric sensor are described. The sensor incorporates a liquid polymeric membrane consisting of phenH-tetraphenylborate, nitrophenyloctyl ether, and poly(vinyl chloride) as ion exchanger, plasticizer, and polymeric support, respectively. The sensor ...

The use of various types of graphite as indicator electrodes in potentiometry has been limited to acid-base and redox titrations. We have expanded the range of feasible titrations to: (1) precipitation titrations; (2) acid-base titrations; (3) compleximetric titrations; and (4) redox ...

protonation constants of the ligand were determined by potentiometric titrations and 1 H- NMR and assigned are reagent grade or higher. Potentiometry Potentiometric titrations were performed in a glass vessel jacketed by an inert atmosphere (N2) during the titration. The hydrogen ion ...

The cost of various commercial indicating electrodes ranges from about $40 for pH electrodes to as much as $355 for a potassium ion-selective electrode. This cost can be reduced to less than $1.50, and in some cases to mere pennies by making sensors from graphite rods and pencils for use in potentiometric titrations. The same sensor can be used for many ...

By using calcium ion selective electrode (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 ...

A potentiometric titration method for determinig high-equivalent-weight sulfonates has been developed. This method utilizes a precipitation reaction between sulfonate and quaternary ammonium ions. A PVC (polyvinyl chloride) membrane electrode, which responds to the quaternary ammonium titrant, signals the end point of the titration. ...

Dissociation Behavior of Poly(maleic acid): Potentiometric Titrations, Viscometry, Pulsed Field titrations, pulsed field gradient NMR, and viscometry of poly(maleic acid) have been carried out in different(carboxylic acid)s, PAA can certainly not be considered as the archetypal molecule. In particular, poly(maleic acid

An automated process was developed, which allows the determination of the concentrations of calcium, magnesium, sulfate, carbonate, phosphate and ammonia in aqueous solutions by potentiometric titration techniques. The apparatus consists of a titrator, wh...

In order to obtain a deeper insight into effects occurring when an electrolyte solution is added to a solution of a strong polyelectrolyte, the microcalorimetric and potentiometric titrations of poly(sodium 4-styrenesulfonate) (Na(+)PSS(-)) solution with different alkali, earth-alkali and tetraalkylammonium nitrate, perchlorate and chloride solutions were ...

The potentiometric determination of sulphur in organic compounds has been studied. After combustion in an oxygen flask the resulting sulphate ions are precipitated by barium acetate, the excess of barium ions being titrated with sodium tetraphenylborate i...

A versatile automatic recording photometric titrator, suitable for colorimetric, nephelometric, and chemiluminescent indicator titrimetry, was assembled from a Precision-Dow recording potentiometric titrator, a modified Beckman Model B spectrophotometer, and necessary intermediate electronic components. The operation of the ...

A new method for the determination of ion exchange equilibrium constants is developed. A technique based in the application of potentiometric titrations is used in the study of non selective strong acidic resins. Potentiometric titrations are carried out without constant ionic strength, so a mathematical treatment ...

... The (Bu4N)4H2SiW11O39Cu (I) salt (soluble in acetonitrile) was isolated and characterized by analysis, potentiometric titration and ESR ...

Solution studies on the binding properties of 4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione (Et(4)todit) toward a number of cationic species including some lanthanide ions revealed the occurrence of a selective 1:1 complexation of the ligand with Sm(3+) ion. Consequently, Et(4)todit was used as a suitable neutral ionophore for the preparation ...

A new oxidimetric titrant, bromamine-B (sodium salt of N-bromobenzenesulphonamide) is introduced for use in aqueous medium. Direct potentiometric and visual end-point titrations and back-titration procedures have been developed for the determination of typical reductants. PMID:18962754

A study was made of H⁺, Na⁺, K⁺, Ca⁺⁺, and Mg⁺⁺ binding and ion-exchange properties of the plasma-mesosome membrane system isolated from Micrococcus lysodeikticus strain NCTC 2665. Titration curves were obtained on membranes prepared according to the method of M. ...

A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctyphthalate in tetrahydrofuran. The reference electrode was an Ag/AgCl single-junction electrode. The sensor was used in precipitation, acid-base, compleximetric, and redox titrations. Preparation ...

The advantages of applying two indicator electrodes in complexometric potentiometric multicomponent titration are shown by means of simulated titration curves. Two measurement arrangements have been considered, one in which the indicator electrodes are directly connected to a voltmeter and the other in which the electrodes are ...

An equation is given which describes the potential change during complexometric titration of metals with potentiometric end-point detection. The potential of the indicator electrode (e.g., silver or mercury electrode) depends on the equilibrium of the reaction MY + W right harpoon over left harpoon WY + M, where W represents the indicator metal ion, and M ...

This paper describes a method for the determination of the so-called wash amines and their degradation products, including ammonium ions, in process liquids and wastewater generated during the desulfurization of hydrogen sulfide gas in the process of crude oil refining and also reports the results of related studies. Ion-exchange liquid chromatography employing an inexpensive ...

Y{sub x}Ba{sub y}Cu{sub z}O{sub 7-{delta}} ceramics forming at isobaric conditions were studied by x-ray diffraction analysis, dynamic magnetic measurements and potentiometric titration. It was established that compositions: 0.8 {le} x {le} 1.2, y=2, z=3; x=1, 1.8 {le} y {le} 2.2, z=3; x=1, y=2, 2.7 {le} z {le} 3.4: are in the homogeneity range of 123. It ...

A fast method for sample treatment of phosphate rock has been developed for the purpose of quantitative leaching (98-100%) of fluoride but less of the interfering cations such as iron and aluminum. Citric acid (0.5 M) was used to extract fluoride in 15-45 min. Leaching of iron and aluminum is minimal, and these ions are complexed with citric acid. The leaching method was ...

A tetraphenylboron (TPB)-ion-selective poly(vinyl chloride)-membrane electrode based on an ion pair complex of TPB/sup -/ with hexadecylpyridinium cation (HDP/sup +/) was prepared with dioctyl phthalate as a plasticizer. Effects of changing the ion pair percent in the membrane and pH of the test solution on the electrode potential were studied. It was found that soaking the ...

Poly(vinyl chloride) based membranes of di-(2-ethylhexyl)phosphoric acid (DEHPA) and dibutyl(butyl)phosphonate (DBBP) have been prepared and investigated as VO(2+)-selective sensors. The membranes containing DEHPA/DBBP and sodium tetraphenylborate, an anion excluder, show near-Nernstian/Nernstian response in the concentration range approximately 10(-5)-10(-1) M. The sensors exhibit a fast response ...

Acids, bases and neutral nitrogen compounds from high-boiling petroleum distillates were separated and further fractionated into fractions containing nitrogen compound types by HPLC on neutral alumina. Acids and bases were separated with anion and cation exchange resins respectively while the neutral nitrogen compounds were removed by complexation with ferric chloride ...

A potentiometric titration study of organic base hydrohalides and quaternary ammonium salts using perchloric acid as the titrant and a mixture of acetic anhydride and acetic acid as the solvent was carried out and the titration mixture was analysed by NMR in order to clarify the chemistry of the reactions involved. It was found that in ...

A theoretical treatment of potentiometric data is applied to calculate coextraction constants (K(IA)) for three potassium salts from water into a liquid nitrobenzene phase. The experiment involves treating nitrobenzene as a membrane and contacting it with two aqueous solutions of different ion activities. In the presence of either a cation or anion ...

The formation of the monochloroiron(II) complex, FeCl + , was studied potentiometrically from 125 to 295�C at 25 degree intervals at one molal ionic strength in aqueous solutions containing acetic acid, sodium acetate, and sodium trifluoromethanesulfonate. In this method, competition between chloride and acetate ions for the ferrous cation resulted in a ...

A nonaqueous titration procedure is described for determining aminoacetic acid and nicotinic acid in mixtures and elixirs. The effect of acetylated aminoacetic acid on the potentiometric titration of nicotinic acid is discussed. Above a 2:1 ration of aminoacetic acid to nicotinic acid, the former interferes with ...

Ionizable amino lipids are being pursued as an important class of materials for delivering small interfering RNA (siRNA) therapeutics, and research is being conducted to elucidate the structure-activity relationships (SAR) of these lipids. The pK(a) of cationic lipid headgroups is one of the critical physiochemical properties of interest due to the strong impact of lipid ...

A procedure is described for classifying nitrogen in petroleum into five different types - strongly basic nitrogen, three types of weakly basic nitrogen, and nontritratable nitrogen. The five types of nitrogen are determined by titrating oils potentiometrically in acetic anhydride with perchloric acid before and after reduction with lithium aluminum ...

A liquid-membrane ion-selective electrode was developed for determining bisbenzene-chromium and its electrochemical and analytical characteristics studied. Methods have also been developed for determining bisarenechromium compounds in the industrial product and its waste waters by potentiometric titration with sodium tetraphenylborate solution.

A two-step curve is expected in the potentiometric titration of Fe(II)-Sn(II) mixtures with Ce(IV) in H sub 2 SO sub 4 . Each end point should indicate the respective oxidation of Sn(II) and Fe(II). However, experimentally only one end point was found; it...

Describes: (1) a FORTH-language, computer-controlled potentiometric titration; (2) coulometric titrations using computer-interfaced potentiometric endpoint detection; (3) interfacing a scanning infrared spectrophotometer to a microcomputer; (4) demonstrations of signal-to-noise enhancement (digital filtering); (5) ...

A potentiometric method of determination of the free nitric acid in trilaurylamine solutions containing plutonium or thorium nitrates is described. The potentiometric titration is carried out in a mixtrue of benzene and 1, 2-dichloro ethane with a standar...

The potentiometric behavior of zirconium in fluoride, nitrate, and fluoride-nitrate systems is correlated and discussed in terms of the zirconium species present. A potentiometric titration was used successfully for the determination of total nitrate and zirconium in aqueous or organic (tributyl phosphate) zirconium-nitrate ...

Nonaqueous potentiometric titration and elemental analysis were used to study basic and nonbasic functionalities present in high-boiling distillates of four Saudi Arabian crude oils. Model nitrogen compounds were titrated under similar titration conditions to differentiate them into strong, weak and nonbasic ...

A new type of screen-printed ion-selective electrode for the determination of cetylpyridinium chloride (CPC) is presented. These new electrodes involve in situ, modified and unmodified screen-printed ion-selective electrodes for the determination of CPC. The screen-printed electrodes (SPEs) show a stable, near-Nernstian response for 1 x 10(-2) to 1 x 10(-6) M CPC at 25 degrees C over the pH range ...

Ethylenediaminetetraacetate anions, EDTA{sup 4-}, were titrated in a hydrogen-electrode concentration cell with an acidic titrant from 0 to 150{degrees}C at 25{degrees}C intervals. These titrations were carried out in the presence of 0. 1, 0.2, and 1.0 mol{center_dot}kg{sup -1} with the supporting electrolytes, sodium chloride, NaCl, and 1.0 ...

A new technique based on the combined use of potentiometric titration and ion-selective electrodes is proposed for determining apparent stability constants (successive stability constants and overall stability constants) of divalent metal cation (Cu/sup 2 +/, Pb/sup 2 +/, and Cd/sup 2 +/) complexes with humic acids. Fourteen humic ...

The construction and general performance of thirteen new polymeric membrane sensors for the determination of fexofenadine hydrochloride based on its ion exchange with reineckate, tetraphenylborate and tetraiodomercurate have been studied. The effects of membrane composition, type of plasticizer, pH value of sample solution and concentration of the analyte in the sensor internal solution have been ...

A complex between sodium nitroprusside (NP) and acetaldehyde of 1:1 in aqueous solution of pH 10 has been prepared and used as an analytical reagent for the spectrophotometric determination of sulfite and nitrite ions. Nitrite ion can be titrated against sulfite ion and vise versa in equivalent amounts with high accuracy in the presence of the acetaldehyde complex of ...

The photometric titration technique is used for the determination of weak bases using perchloric acid in acetic acid as titrant and acetic acid or acetonitrile as solvent. Differentiating titration of as many as four components in a single mixture is shown to be possible. Comparison with potentiometric ...

Poly-o-anisidine Sn(IV) arsenophosphate is a newly synthesized nanocomposite material and has been characterized on the basis of its chemical composition, ion exchange capacity, TGA-DTA, FTIR, X-RAY, SEM, and TEM studies. On the basis of distribution studies, the exchanger was found to be highly selective for lead that is an environmental pollutant. For the detection of lead in water a ...

Mixed oxides Ce(1-x)Zr(x)O(2) prepared by slow coprecipitation in NaOH were tested for NO(2) adsorption in dynamic conditions at room temperature. The samples were characterized before and after exposure to NO(2) by XRD, N(2)-adsorption, thermal analysis, potentiometric titration, and FT-IR. Mixed oxides show a better NO(2) adsorption capacity than the ...

acids is titrated with standard base. Because the pH does not change abruptly enough at either from a derivative plot; that is, (pH)/(vol) vs. volume of base added. A mixture of two acids can, plot the data for each titration (pH vs. volume of base added). The sulfamic acid (standardization

C. P. SCHULTHESS AND D. L. SPARKS2 ABSTRACT Batch potentiometric titration analyses were made on a 7 of titration (ZPT) supernatant.All three methods resulted in similarcharge isotherms and a zero point of charge (ZPC) = 8.60. A fourth titrationmethod was developed involving each supernatantof the batch titration

A method based on the quantitative reaction of uranyl nitrate with hydrogen peroxide to release nitric acid is presented for the determination of uranyl nitrate in nitric acid solution. The hydrogen peroxide is added to the uranyl nitrate solution and the total nitric acid determined by visual or potentiometric titration with sodium hydroxide. ...

constants and Gibbs free energy at 25 to 70 C. Fig. 1 shows the potentiometric titration data for the uranyl complexes form during the titration. The overall complexation reactions are represented by equilibrium (2 in Table 2. To show the goodness of the constants, simulated titration curves were calculated with ...

Electrolytically generated iron (III) was used as an oxidant in coulometric titrations in molten lithium chloride--potassium chioride at 460 deg C to titrate chromium (II) to chromium (III) and vanadium (II) to vanadium (III). The potentiometric amperometric with one electrode, and the dead-stop methods of end point detection ...

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, ...

A two-phase potentiometric titration procedure of barbiturates with mercury(II) was developed. The composition of the formed mercury-barbiturate complexes was elucidated by infrared spectrometry. In the new titration procedure the barbituric acid derivative is dissolved in an aqueous borate buffer. An organic phase consisting of ...

In the present study, the sorption of europium and lutetium onto titanium dioxide from aqueous solutions is presented, as a function of pH, ionic strength and concentration. An acid base model for the titanium dioxide surface was determined from potentiometric titrations and zeta-potential measurements. The common intersection point of ...

The points of zero charge/potential of proteins depend not only on pH but also on how they are measured. They depends also on background salt solution type and concentration. The protein isoelectric point (IEP) is determined by electrokinetical measurements, whereas the isoionic point (IIP) is determined by potentiometric titrations. Here we use ...

In this study a PVC membrane electrode for determination of ketotifen fumarate is reported, where ketotifen tetraphenylborate (Keto-TPB) was used as ion exchanger. The electrode has linear range of 5.6x10(-6)-1.0x10(-2) and 1.0x10(-5)-1.0x10(-2) mol/L, with detection limits 2.37x10(-6)and 4.60x10(-6) mol/L in batch and flow injection analysis (FIA), respectively. The electrodes show a Nernstian ...

A screen-printed electrode (SPE) was fabricated for the determination of 1-(ethoxycarbonyl)pentadecyltrimethylammonium bromide (Septonex) based on the use of Septonex-tetraphenylborate as the electroactive substance, and o-nitrophenyloctylether (o-NPOE) as the plasticizing agent. The electrode passes a near-Nernstian cationic slope of 59.33 � 0.85 mV from activity between pH ...

The construction and characteristic performance of metoclopramide (MCP)-polyvinyl chloride (PVC) membrane sensor are described. The sensor is based on the use of MCP-tetraiodomercurate ion pair as electroactive material in PVC matrix in presence of dioctylphthalate (DOP) as solvent mediator. MCP membrane sensor shows a stable, near Nernstian response over the concentration range 1 x 10(-2)-6 x ...

This paper describes the development of screen-printed (SPE) and carbon paste (CPE) sensors for the rapid and sensitive quantification of naphazoline hydrochloride (NPZ) in pharmaceutical formulations. This work compares the electroactivity of conventional carbon paste and screen-printed carbon paste electrodes towards potentiometric titration of NPZ. The ...

Membrane incorporating [Mg{(TAP)(SBn)(8)}] complex, (I), as ionophore with composition I:NaTPB:DOP:PVC in the ratio 10:2:133:200 (w/w) exhibits the best result for potentiometric sensing of Mg(2+) ions. This gives linear potential response in the concentration range of 9.4x10(-6) to 1.0x10(-1)M with a slope of 29.2+/-0.4mV per decade of activity of Mg(2+). Standard deviation ...

The "acid nature" of humic acid has been controversial for many years. Some investigators claim that humic acid is a true weak acid, while others feel that its behaviour during potentiometric titration can be accounted for by colloidal adsorption of hydrogen ions. The acid character of humic acid has been reinvestigated using newly-derived relationships ...

A continuous wavelet transform with a specially defined dedicated mother wavelet is applied for data treatment as a signal-processing tool in a potentiometric titration. The inflection points of the titration curve are localized in one step of the calculations. The imperfection of signal, random noise, or spikes has no influence on the ...

The lower levels of the potentiometric titration of chloride with silver ions were investigated. The titrant was 0.001N acetonic silver perchlorate. The titration media were acetone and acetic anhydride:acetone (4:1). A silver sulfide ion-selective indicator electrode and a double-junction reference electrode were used to monitor ...

We have evaluated the following new titrants for the potentiometric precipitation titration of perchlorate: cetyltrimethylammonium chloride (CETAC), cetyltrimethylammonium bromide (CETAB), cetylpyridinium chloride (CPC), and benzyldimethyltetradecylammonium chloride (BDTAC). Titrations were monitored with a fluoroborate ion-selective ...

Bromamine-B is proposed as an oxidimetric titrant for potentiometric and visual end-point titrations of arsenic(II), hexacyanoferrate(II), antimony(III), hydroquinone, semicarbazide hydrochloride, isonicotinic acid hydrazide, hydrazine sulphate, ascorbic acid, phenylhydrazine hydrochloride and metol. Quinoline Yellow, naphthidine, ...

It is shown that the ionization constants of diacidic compounds can be determined by utilizing potentiometric titration data, even when a precipitate forms during the titration. The two methods presented are particularly useful for compounds for which the pK alpha values are close together. A third method is presented which can be used ...

Modern ideas about acid-base equilibria in amphiprotic solvents (acetonitrile, dimethylformamide, ketones, and others) are discussed. Data are presented for the homoconjugation constants of phenol and benzoic acid derivatives in these solvents and the calculation of acid-base titration curves is described. The question of the solvent acidity scales and their relative positions ...

The solution reaction mechanisms, composition, donor atoms, properties of coordinate link and stability of the complexes on the systems of adrenaline with Nd3+, Gd3+ and Tm3+ have been studied by pH-potentiometric titration and electronic spectroscopy. Ad...

The objective of this project is to conduct extensive studies on the surface reactivity of pyrite by using electrochemical, surface analysis, potentiometric and calorimetric titration, and surface hydrophobicity characterization techniques and to correlat...

The objective of this project is to conduct extensive studies on the surface reactivity of pyrite by using electrochemical, surface analysis, potentiometric and calorimetric titration, and surface hydrophobicity characterization techniques and to correlat...

The objective of this project is to conduct extensive studies on the surfaces reactivity of pyrite by using electrochemical, surface analysis, potentiometric and calorimetric titration, and surface hydrophobicity characterization techniques and to correla...

The objective of this project is to conduct extensive studies on the surface reactivity of pyrite by using electrochemical, surface analysis, potentiometric and calorimetric titration, and surface hydrophobicity characterization techniques and to correlat...

The objective of this project is to conduct extensive studies on the surface reactivity of pyrite by using electrochemical, surface analysis, potentiometric and calorimetric titration, and surface hydrophobicity characterization techniques and to correlat...

Potentiometric method is employed by using memotitrator coupled with combined electrode for the estimation of plutonium. The estimations are carried out on the process samples and the acid dissolved samples for auditing, in the concentration range of 5 g/...

Reactions of Cr(VI) with diphenylcarbazide and Cr (II with diphenylcarbazone (DPCN) were investigated spectrophotometrically and by potentiometric titration. The investigations concerned the course the reactions run with an excess of the reagents, conditions of extraction of the colored product, and the behavior of DPCN in solutions of organic and ...

Analytical research and development work is reported on multielement analysis, time-resolved spectroscopy, fluorescence analysis, ionization potential of NP, excited state chemistry, polarized x ray sources, potentiometric titration of Na, determination o...

A study of the distribution of the electric charges in the Ap and B2 horizons of two highly weathered Oxisols and one Alfisol from Brazil was made by means of potentiometric titration and by direct measurement of adsorption of ions in the presence of vary...

The following work was done: (1) Development of the mathematics for the estimation of the ISE time constant. (2) Development of the inverse filter and a correction algorithm to improve the estimate of the equivalence point for potentiometric titration usi...

A procedure for the determination of hydroxide concentration in the presence of aluminate and other interfering ions was developed using the method of standard additions (or more specifically in this case, standard subtractions). The procedure called for ...

To determine total chloride content in TATB, the sample was burned in a Parr Bomb, and the chlorides formed were titrated potentiometrically using silver nitrate. The electrode system is a chloride specific ion sensing element and a single junction refere...

The main processes of sugar industry are carried out in aqueous solutions, hence the stability of sucrose in aqueous media is of utmost interest for industry. Potentiometric titration is the most convenient method of determination of ionization constants,...

The decavanadate structure of the vanadate acids was confirmed by the method of potentiometric sunface applied to the titration curve of decavanadate acids and measurement of the pK of its fifth and sixth acidities with the aid of this curve. The results obtained were used to study the metavanadate-vanadate equilibrium. (tr-auth)

Chemical surface complexation models were developed to describe potentiometric titration and ion adsorption data on oxide minerals. These models provide molecular descriptions of adsorption using an equilibrium approach that defines surface species, chemical reactions, mass and charge balances and ...

Physical and electrochemical properties are reported for SbCl/sub 3/-AlCl/sub 3/-N-(1-butyl)pyridinium chloride (BPCl) mixtures that are liquid at ambient temperatures, and studies of the electrogeneration and open-circuit decay of some arene radical cations, both in this medium and in SbCl/sub 3/-KCl at elevated temperatures, are described. Specific conductivities, densities, ...

A new liquid membrane electrode which responds to trinitrobenzenesulfonate (TNBS-) ion is described. The electrode exhibits very good experimental characteristics: (i) The working pH range is 2.0-12.5; (ii) its response is consistent with the Nernst equation in the range 1.10(-1)-5.10(-5) M; (iii) its response time is 5 s; and (iv) its selectivity for TNBS- against 14 tested ions is very high. ...

The construction and electrochemical response characteristics of poly(vinyl chloride) membrane sensors for pioglitazone HCl (PG) are described. The sensing membranes incorporate ion association complexes of pioglitazone cation and sodium tetraphenylborate (NaTPB) (sensor 1) or phosphomolybdic acid (PMA) (sensor 2) or phosphotungstic acid (PTA) (sensor 3) as electroactive ...

Improved methods for the preparation of imidotetraalkylpyrophosphates are reported. The dissociation constant of the water soluble tetraethyl analogue was determined by potentiometric titration. The values for the partition constant and aggregation constant of the tetradodecyl analogue were determined by two phase EMF potentiometric ...

Analysis of the product obtained by the precipitation of uranyl nitrate with ammonium hydroxide, in the Springfields process, indicated that its composition did not correspond to the formula (NH/sub 4/)/sub 2/U/sub 2/O/sub 7/, normally ascribed to it. The proportion of ammonium ion in the product was found to be less than the 5.77% required by this formula. By ...

The utilization of chromic salts for reducing the uranium (VI) from chloridic solutions, for potentiometric dosage is described. This method is used in the range of 0,002 to 1,0 M of uranium. (C.G.C.). (Atomindex citation 24:044216)

The most significant recent developments in methods for the determination of anions including iodides have involved (1) the use of ion- selective electrodes in direct potentiometric measurements and potentiometric titrations, (2) the application of indirect and chemical amplification techniques in atomic absorption spectrometry, ...

Potentiometric titration of uranium with Fe/sub 2/(SO/sub 4/)/sub 3/, usin g Cd as reducing agent was studied. The acidity and sensitivity of this reaction were determined. This method yields good results for the uranite group, if phosphate is first removed by ion exchange with Amberlite IR-120. (auth)

A potentiometric method for the determination of aluminum in nickel-base heat-resistant alloys was developed. The aluminum is titrated with sodium fiuoride in a hydrochloric acid medium buffered with sodium acetate. An Al-Ni/Cr electrode is used. The interfering elements were determined, and methods of removing them were investigated. The ...

Two methods are described which allow quick thorium assay easily to be automated. In the potentiometric titration with NaF the ion sensitive fluoride electrode is used as the indicator. The analysis can be performed for pH values 3 to 4. Th(OH) sub 4 prec...

A potentiometric method is presented for the determination of up to 0.05% U in ores. The U/sup 6+/ is reduced with liquid Zn amalgam in a stream of air and titrated with (0.01N) permanganate or Ce(SO/sub 4/)/sub 2/. The interfering elements are removed by electrolysis at the Hg cathode and extraction of their cupferrates into chloroform. ...

A two-phase potentiometric titration procedure for barbiturates with mercury(II) was developed. In the new titration procedure the barbituric acid derivative is dissolved in an aqueous borate buffer. An organic phase consisting of chloroform and benzyl alcohol is added, and the vigourously stirred contents of the ...

We studied complex formation in an aqueous salt-free system (pH approximately 3 and at 25 degrees C) between nanogel particles having opposite charges. Anionic gel (AG) and cationic gel (CG) particles consist of lightly cross-linked N-isopropylacrylamide (NIPA) copolymers with 2-acrylamido-2-methylpropane sulfonic acid and with 1-vinylimidazole, respectively. The number of ...

Acidic-basic characteristics of ionogenic groups of dietary fibers (DF) isolated from various raw materials were determined by potentiometric titration of DF using a method of individual weights and the ion-exchange properties of DF were estimated. The cation-exchanging ability of DF is within the range 0.2-1.5 meq/g DF. The calculated ...

We report on interpolyelectrolyte complexes (IPECs) formed by micelles of ionic amphiphilic diblock copolymers with polyisobutylene (PIB) and poly(sodium methacrylate) (PMANa) blocks interacting with quaternized poly(4-vinylpyridine) (P4VPQ). The interpolyelectrolyte complexation was followed by turbidimetry and small angle neutron scattering (SANS). The data obtained by means of a combination of ...

In this study, poly(amic acid)-modified biomass was prepared to improve the adsorption capacities for two cationic dyes, methylene blue and basic magenta. X-ray photoelectron spectroscopy and potentiometric titration demonstrated that a large number of imide, amine, and carboxyl groups were introduced on the biomass surface, and the ...

The charge characteristics of two kinds of commercial nanofiltration (NF) membranes, DK and MPF-34, were investigated. In the present study, the membrane potentials across NF membranes were measured in various electrolyte solutions�HCl, KCl, NaCl, and MgSO4. The experimental results were analyzed based on the Donnan equilibrium and the Nernst Planck equation of ion flux, and theoretical ...

We present novel intelligent colloidal polymer/silica nanocomposites, in which the complexation of cationic silica nanoparticles and a weak anionic polyelectrolyte can be manipulated simply by pH change through a hydrogen-bonding interaction and ionic complexation caused by hydrogen-transfer interactions between the constituents. Special silica particles which have nanometer ...

Graphite oxide (GO) synthesized from commercial graphite was modified with aluminium or zirconium-aluminium polyoxycations and then calcined at 350 degrees C. On the samples obtained adsorption of ammonia from moist air was investigated. The surface of materials before and after exposure to ammonia was characterized using adsorption of nitrogen, XRD, SEM, FTIR, TA, CHN analysis, and ...

N-[2-[4-[[[(Cyclohexylamino)carbonyl]amino]sulfonyl]phenyl]ethyl]-5-methyl pyrazine carboxamide (glipizid) was explored as an electro-active material for preparing a polymeric membrane-based sensor selective to samarium ions. The membrane incorporated 30% poly(vinyl chloride) (PVC), 53% benzyl acetate (BA), 11% glipizid and 6% sodium tetraphenyl borate. When coated on the surface of a graphite ...

Four chemically modified chelating silica gel phases (I - IV) with ion exchange groups were tested for their potential capability to selectively bind, extract and preconcentrate uranyl ions (UO(2)(2+)) from different aqueous solutions as well as ore samples. Factors affecting such determination processes were studied and optimized. These included the pH of the contact solution, the mass of the ...

A series of recently synthesized benzo- and pyridine-substituted macrocyclic diamides were studied to characterize their abilities as lead ion carriers in PVC membrane electrodes. The electrode based on 3,15,21-triaza-4,5;13,14-dibenzo-6,9,12-trioxabicycloheneicosa-1,17,19-triene-2,16-dione exhibits a Nernstian response for Pb2+ ions over a wide concentration range (1.3 x 10(-2) to 3.6 x 10(-6) ...

An application of polyelectrolyte-enhanced ultrafiltration utilizes cationic polyelectrolytes to electrostatically bind anionic species. The colloid and target anion are then concentrated using an ultrafilter, producing a filtrate with a lower concentration of the target. This study compared the performances of poly(4-vinylpyridine) (P4VP) and poly(diallyldimethylammonium) ...

The present invention is an improved method and related apparatus for quantitatively analyzing machine working fluids and other aqueous compositions such as wastewater which contain various mixtures of cationic, neutral, and/or anionic surfactants, soluble soaps, and the like. The method utilizes a single-phase, non-aqueous, reactive titration composition ...

The present invention is an improved method and related apparatus for quantitatively analyzing machine working fluids and other aqueous compositions such as wastewater which contain various mixtures of cationic, neutral, and/or anionic surfactants, soluble soaps, and the like. The method utilizes a single-phase, non-aqueous, reactive titration composition ...

Surface charge and UO{sub 2}{sup 2+} adsorption were measured on a clay-sized, subsurface mineral isolate whose mineralogy was dominated by a ferrogenous beidellite. Experiments were performed in batch at 25{degrees}C with N{sub 2(g)} atmosphere and sorbent suspensions (9.46 g clay/kg suspension) that had been adjusted in pH between 4 and 9. Surface charge was defined by measurements of adsorbed ...

The soil acid-base buffering capacity and the biological availability, mobilization, and transport of macro- and micronutrients, toxic metal ions, and xenobiotic organic cations in soil are strongly influenced by the acid-base properties of humic substances, of which humic and fulvic acids are the major fractions. For these reasons, the proton binding behavior of the humic ...

The X-ray molecular structure and, magnetic, and spectroscopic properties, as well as the analysis of the structural behavior in solution of a novel nickel (II) complex [Ni2(HBPClNOL)2(OAc)](ClO4) 1 are reported. Complex 1 was prepared by the reaction between the ligand H2BPClNOL (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine), [Ni(H2O)6](ClO4)2 and sodium acetate. ...

Research continued to be focused broadly on the chemistry of the actinide cations in solution. While the direct concern is the actinide elements, their radioactivity limits the techniques which can be applied to their study. A major area of interest continues to be the thermodynamics of interaction of the f-elements with a broad spectrum of inorganic and organic ligands. ...

The method used for studying anhydrous acetic acid was potentiometry with a glass electrode. In this way, the titration of common inorganic acids was studied (HClO4, HBr, H2SO4, HC1, HNO3, H3PO4), as were some metallic salts. Furthermore it was found that...

Gold, platinum, and several other platinum metals can be determined by titration with cetylpyridinium chloride (CPC). CPC forms a precipitate with AuCl(sub 4)(sup (minus)) and PtCl(sub 6)(sup 2(minus)). Differentiation of AuCl(sub 4(minus)) and PtCl(sub 6...

Ethylenediaminetetraacetate anions, EDTA(sup 4-), were titrated in a hydrogen-electrode concentration cell with an acidic titrant from 0 to 150(degrees)C at 25(degrees)C intervals. These titrations were carried out in the presence of 0. 1, 0.2, and 1.0 mo...

Sodium fluoride solutions with an initial pH of 4.46 yielded poorly defined endpoint breaks with a pH electrode system and Ce(III) or La(III) as titrants. At this initial pH, however, the fluoride ISE yielded acceptable S-shaped titration curves. At an in...

The sources of amine, carbonate, and silver impurities in tetrabutylammonium hydroxide were investigated, and techniques for their removal were evaluated. The stability of the base in water, isopropanol, tert-butyl alcohol, and pyridine was determined. Salt bridge systems were de vised for acetene, isopropanol, tert-butyl alcohol, and pyridine. Titrations of weak ...

Accomplishments achieved include the development of a digital potentiometric oxygen titration system, design of an Apple-IIe-controlled automatic CO/sub 2/ titration system, and new data sets of pH, alkalinity, and CO/sub 2/ from the Weddell Sea, the Bering Sea, the Pacific Ocean between Alaska and Hawaii and between Kwajalein and ...

Accomplishments achieved include the development of a digital potentiometric oxygen titration system, design of an Apple-IIe-controlled automatic CO sub 2 titration system, and new data sets of pH, alkalinity, and CO sub 2 from the Weddell Sea, the Bering...

A new oxidimetric titrant, bromamine-T (sodium salt of N-bromo-p-toluene sulphonamide), is introduced for use in aqueous medium. Direct potentiometric and visual indicator titration methods as well as back-titration procedures have been developed for the determination of a variety of substances. PMID:18962313

To a sample of the explosive, water was added and the oleic acid converted to the sodium salt by adjusting the pH to 12.2 to 12.5. The sodium oleate was titrated potentiometrically with standard cetylpyridinium chloride. Another sample was dissolved in dimethylsulfoxide and the HMX was titrated vs standard tetrabutylammonium hydroxide. ...

Cetyltrimethylammonium bromide is used in the precipitation titration of perchlorate, with potentiometric end-point detection. A perchlorate, fluoroborate or nitrate ion-selective electrode may be used. The method is more sensitive than the commonly used titration with tetraphenylarsonium chloride. It can be used over the pH range from ...

This method covers the determination of basic constituents in petroleum products by titration with perchloric acid. For many materials the results obtained by this method will be similar to those obtained by Method D 664-IP 177. With certain compounds such as strongly overbased oil additives and nitrogenous polymeric compounds, higher results may be obtained. Summary of ...

Several types of graphite were used as sensors in the potentiometric titration of 25 to 75 ..mu..mol of sulfate vs. lead(II) and barium(II) and compared with titrations obtained with a lead ion-selective electrode (ISE). Pyrolytic graphite and high-density graphite, conditioned in neutral potassium permanganate, were found to be good ...

A platinum electrode, a Radelkis OP-C-7111D graphite electrode and a laboratory-prepared silicone-rubber-based membrane graphite electrode were used in potentiometric titrations of reducing substances with bromine in acetic acid. In determinations of hydroquinone, 2-methylhydroquinone, 2-chlorohydroquinone and ascorbic acid, the Radelkis electrode showed ...

A first attempt has been made to interpret physicochemical data from potentiometric titration analysis in accordance with the complete measurement-uncertainty budget approach (bottom-up) of ISO and Eurachem. A cause-and-effect diagram is established and discussed. Titration data for arsenazo III are used as a basis for this discussion. ...

Equilibrium adsorption experiments, isothermal titration calorimetry and potentiometric titration techniques were employed to investigate the adsorption of Cu(II) by extracellular polymeric substances (EPS) extracted from Pseudomonas putida X4, minerals (montmorillonite and goethite) and their composites. Compared with predicted values ...

Non ideality of acetonitrile-water mixtures was studied from data on the excess of molar volumes and viscosities. pH and autoprotolisis constants were evaluated at the standard state of the mixed solvent from titrations of a strong acid with a strong base. In order to illustrate the evaluation of the aqueous ionisation constant of water insoluble compounds from pH ...

Many solid-state electrodes were found to respond as endpoint detectors in the potentiometric titration of large inorganic and organic anions with quaternary ammonium halides. The best response was obtained with the iodide and cyanide electrodes although practically any electrode can function as endpoint sensor. The titrants were hexadecylpyridinium ...

The reduction conditions for the accurate determination of small amounts of cerium, chromium, and vanadium were studied. On the basis of the results obtained, the determination of these elements, in the presence of permanganate ions, by a single potentiometric titration with a standard hydroquinone solution was investigated. (tr-auth) l6818 A ...

After hydrolytic pretreatment, wood slurries contain substantial amounts of organic acids. Additional acids are produced during the liquefaction step whether or not there is prehydrolysis. The acids have pH's in the range of about 3 to 5 and are easily titrated potentiometrically with sodium hydroxide. Anions present in neutralized slurry or in ...

A method for the determination of sulphated glycosaminoglycans is based on their precipitation with (1-ethoxycarbonyl)pentadecyltrimethylammonium bromide (Septonex), the excess of which is back-titrated with sodium tetraphenylborate. The titration is monitored by a simple coated-wire ion-selective electrode with a plasticized poly(vinyl chloride) membrane ...

The possibility of accurate amperometric titration of low concentrations of nitrite ion with potassium permanganate was confirmed. Difficulties encountered in the rapid microdetermination of mercury in the presence of ethylenediamine also appear to have been overcome. A simple automatic potentiometric titrator was brought to ...

The adsorption of Nd3+ onto rutile surfaces was examined by potentiometric titration from 25 to 250�C, in 0.03 and 0.30m NaCl background electrolyte. Experimental results show that Nd3+ sorbs strongly, even at low temperature, with adsorption commencing below the pHznpc of rutile. In addition, there is a systematic increase in Nd3+ adsorption with ...

Acetylacetone, ethylacetoacetate and salicyldehyde, are reported to form chelates with copper of high stability as compared to other metals. Therefore, PVC based membranes of bis[acetylacetonato] Cu(II) (A), bis[ethylacetoacetate] Cu(II) (B) and bis[salicyldehyde] Cu(II) (C) have been investigated as copper(II) selective sensors. The addition of sodium tetraphenylborate and various plasticizers, ...

Reliable thermodynamic information on the stability of ferrous chloride complexes at high temperatures is important to evaluations of iron transport in hydrothermal fluids, and to the power industry for iron corrosion and transport in the water/steam cycle. The formation of the monochloroiron(II) complex, FeCl[sup +], was studied potentiometrically from 125 to 295[degrees]C at ...

A new poly(vinyl chloride)-based membranes containing p-(4-n-butylphenylazo)calix[4]arene (I) as an electroactive material along with sodiumtetraphenylborate (NaTPB), and dibutyl(butyl)phosphonate in the ratio 10:100:1:200 (I:DBBP:NaTPB:PVC) (w/w) was used to fabricate a new cobalt(II)-selective sensor. It exhibited a working concentration range of 9.2 x 10(-6) to 1.0 x 10(-1)M, with a Nernstian ...

Al(3+) selective sensor has been fabricated from poly(vinyl chloride) (PVC) matrix membranes containing neutral carrier morin as ionophore. Best performance was exhibited by the membrane having composition as morin:PVC:sodium tetraphenyl borate:tri-n-butylphosphate in the ratio 5:150:5:150 (w/w, mg). This membrane worked well over a wide activity range of 5.0x10(-7) to 1.0x10(-1)M of Al(3+) with a ...

A variable-temperature (313 K to 353 K) titration calorimeter of high sensitivity has been constructed. The purpose of the calorimeter is to study temperature effects on the enthalpies of complex formation and of other reactions of metal cations such as h...

A simple but high performance potentiometric titration technique using pulsating sensors has been developed for assay of dissolved oxygen (DO) in water samples down to 10.0 microg L(-1) levels. The technique involves Winkler titration chemistry, commonly used for determination of dissolved oxygen in water at mg L(-1) levels, with ...

Kinetics of the cleavage of two phosphate diesters, bis(4-nitrophenyl) phosphate and 2-hydroxypropyl 4-nitrophenyl phosphate and a triester, 4-nitrophenyl diphenyl phosphate, in the presence of Mg(II), Ca(II) and Sr(II) were studied in 90% vol. DMSO at 37 degrees C. The alkaline hydrolysis of the triester was inhibited by all cations, but with both phosphodiesters strong ...

The construction and general performance characteristics of two novel potentiometric carbon paste electrodes (CPE) responsive to antimony are described. These sensors are based on the use of the ion associate complexes of tetraiodoantimonate (TIA) anion with cetylpyridinium (CP) and triphenyl tetrazolium (TPT) counter cations as ion exchange site in a ...

The extraction of alkali metal cations by the lipophilic crown ether, bis-t-octylbenzo-14-crown-4 (BOB14C4), three derivatives of BOB14C4 having pendant carboxylic acid sidearms, and a lipophilic carboxylic acid, 2-methyl-2-heptylnonanoic acid (HMHN) was studied by two-phase potentiometric titration and ion-chromatography. The ...

Surface charge and UO 2 2+ adsorption were measured on a clay-sized, subsurface mineral isolate whose mineralogy was dominated by a ferrogenous beidellite. Experiments were performed in batch at 25�C with N 2(g) atmosphere and sorbent suspensions (9.46 g clay/kg suspension) that had been adjusted in pH between 4 and 9. Surface charge was defined by measurements of adsorbed Na by isotopic ...

Potentiometric titrations of metal ions with EDTA have been carried out with a platinum or graphite electrode and the Fe(III)/Fe(II) redox system. In the absence of oxygen and for pH < 2 the titration curves may be described by an equation similar to that given previously for titrations with silver and mercury ...

The interaction of submicron metal oxide particles with natural aqueous solutions results in the hydroxylation of surface sites, which impart a pH-dependent surface charge. The charged submicron particles influence processes such as nanoparticle assembly and alteration, crystal growth rates and morphologies, colloid flocculation, and contaminant transport. The surface charge and ion sorption ...

A detailed study of the chemical characteristics of mine soils derived from the Wise formation in Southwest Virginia was undertaken using a number of standard techniques. The mine soils studied ranged in age from 4 to 20 years, and were derived from sandstones and siltstones high in carbonates and iron. The wet acid-dichromate digestion organic matter technique often yields questionably high ...

The authors understanding of the chemistry, structure, and reactions of organic substances in forest floor leachates is limited and incomplete. Therefore, the authors examined the organic and inorganic chemistry of forest floor leachates collected from a hardwood forest in central Maine over a two-year period (1987-1989), including detailed study of dissolved organic carbon (DOC). Seasonal ...

The aims of this study are to develop, characterize and optimize a novel treatment scheme that would be effective simultaneously against the toxic organics and the heavy metals present in coal conversion waste waters. A specific goal of the study is to remove and recover cationic and anionic heavy metals from aqueous solutions and coal conversion waste waters using ...

The Broensted acidity of H-mordenite and H-ZSM-5 samples of varying proton concentration has been studied using aqueous conductometric titration, IR spectroscopy, and aqueous potentiometric titration. Good agreement is observed between Broensted acid site concentrations determined by conductometric titration and IR ...

Jun 16, 2011 ... Cation-anion balance or titration methods should be more reliable. The flux of H + ions in soil systems due to plant uptake processes and ...

A differential pH and thermal titrimeter has been used to determine the ionization constants of EDTA and EGTA as well as their calcium complexes. The intrinsic heat of binding is a constant for the pH range 2-11.5 for both substances and is found to be -5.4 kcal mol for EDTA and -7.9 kcal mol-1 for EGTA. The binding constants evaluated by fitting to the potentiometric curves ...