Coated wire chromium(III) ion-selective electrode based on azamacrocycles

Tetraazacyclotetradecane, tetratosyltetraaza 12C4, and tritosyltriaza 9C3 have been explored as electroactive materials for preparing coated wire ion-selective electrodes (CWISEs) for Cr(III) ions. The best performance was observed for the membrane comprising electroactive material (tetratosyltetraaza 12C4), plasticizer (dibutyl phthalate), and poly(vinyl chloride) in the optimum ratio 5:60:35 (w/w). Linear Nernstian response for this electrode was obtained over the total Cr(III) concentration range of 1×10^–1 to 1×10^–7 M in 0.05 M NH₄NO₃ medium, with a slope of 20±1 mV per decade change. The working pH range of the electrode was 1.8–5.5. Selectivity coefficients of some mono, divalent, and trivalent metal ions were determined. Analyses of electroplating bath solutions, chromating, and effluent samples have been carried out using this CWISE and the results are found to be comparable with those obtained by using conventional methods or by AAS.     

Mercury(II) ion-selective electrodes based on heterocyclic systems

Mercury ion-selective electrodes (ISEs) were prepared with a polymeric membrane based on heterocyclic systems: 2-methylsulfanyl-4-(4-nitro-phenyl)-l-p-tolyl-1H-imidazole (I) and 2,4-diphenyl-l-p-tolyl-1H-imidazole (II) as the ionophores. Several ISEs were conditioned and tested for the selection of common ions. The electrodes based on these ionophores showed a good potentiometric response for Hg2+ ions over a wide concentration range of 5.0 x 10(5-) - 1.0 x 10(-1)M with near-Nernstian slopes. Stable potentiometric signals were obtained within a short time period of 20 s. The detection limits, the working pH range of the electrodes were 1.0 x 10(-5) M and 1.6-4.4 respectively. The electrodes showed better selectivity for Hg2+ ions over many of the alkali, alkaline-earth and heavy metal ions. Also sharp end points were obtained when these sensors were used as indicator electrodes for the potentiometric titration of Hg2+ ions with iodide ions.     

The selective trimerisation of isoprene with chromium N,N-bis(diarylphosphino)amine catalysts

Chromium catalysts supported by N,N-bis(diarylphosphino)amine ligands, on activation with methyl aluminoxane (MAO), selectively trimerise isoprene with unprecedented activity to predominantly linear materials.     

Bio-sensors based on ion-selective electrodes

Summary A review is given on bio-sensors based on ion-selective electrodes. By means of several examples of enzyme electrodes the salient features and the operating principles of the new sensors are illustrated. 72 literature references.

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Biosensoren auf der Grundlage von ionenselektiven Elektroden

Zusammenfassung Ein Überblick über Biosensoren wird gegeben. An Hand mehrerer Beispiele von Enzymelektroden werden die entscheidenden Eigenschaften und die prinzipielle Arbeitsweise dieser neuen Sensoren dargestellt. 72 Literaturzitate.

     

Spectroscopy study on the photochromism of Schiff bases N,N'-bis(salicylidene)-1,2-diaminoethane and N,N'-bis(salicylidene)-1,6-hexanediamine

The photochromism of Schiff bases N,N'-bis(salicylidene)-1,2-diaminoethane (BSE) and N,N'-bis(salicylidene)-1,6-cyclohexanediamine (BSH) was studied by steady-state and time-dependent fluorescence, UV Vis absorption spectroscopy and theoretical chemistry calculations. The experimental results show that BSH can perform the photochromism easier than BSE, may be due to the molecular topology difference.     

Investigation of ion-selective electrodes based on quaternary phosphonium salts: Part 2. A tetrachlorothallate(III) Ion-Selective Electrode

A tetrachlorothallate(III)-selective electrode based on the tetradecylphosphonium tetrachlorothallate(III) ion-pair complex in a PVC membrane is described. The mechanism of the influence of the hydrochloric acid content of sample solutions is discussed in detail. Electrode membranes made with and without dubutyl phthalate as plasticizer were investigated. The membranes without plasticizer are better with regard to selectivity and limit of detection (2 × 10^?7 mol 1^?1).     

Chromium(III) ion-selective electrode based on 4-dimethylaminoazobenzene

A PVC-based membrane of 4-dimethylaminoazobenzene reveals a Nernstian potentiometric response (with slope of 19.5+/-0.6 mV/decade and a correlation coefficient of 0.999) for Cr(III) over a wide concentration range (1.66 x 10(-6)-1.0 x10(-2) mol dm(-3)). The potential of this electrode is independent of pH in the range of 3.0-5.5. It has a fast response time of about 10 s and was used for a period of 3 months with good reproducibility. The detection limits of this membrane electrode was 8 x 10(-7) M. the proposed electrode has been used as an indicator electrode in the potentiometric titration of Cr(III) with EDTA. This sensor exhibits a very good selectivities for Cr(III) over a wide variety of metal ions.     

Potentiometric behavior of N,N,N',N'-tetrabenzylmethylenediamine-based hydrogen ion-selective electrodes

H(+)-ion selective electrodes (H(+)-ISE) based on N,N,N',N'-tetrabenzylalkylenediamine (alkylene: methylene, ethylene, propylene, hexylene) are prepared. We are compared with their response potentials to carbon numbers between diamino groups. They were showed linear selective to hydrogen ion in the range of pH 1.5-9.0, 2.5-9.0, 3.5-9.0 and 4.0-9.0, and their Nernstian slopes were 57.3, 53.5, 57.4 and 56.1 mV pH(-1) at 20+/-0.2 degrees C (theoretical value: 58.2 mV pH(-1)), respectively. The interference effect on the cations were measured to alkali metal ions, alkaline earth metals ions. Selectivity coefficients were measured by the mixed-solution method. Among all electrodes the N,N,N',N'-tetrabenzylmethylenediamine (TBMDA)-based electrode has shown the best selectivity in acidic solution.     

Theory and applications of ion-selective electrodes Part III

This review of ion-selective electrodes is arranged in the same way as Parts I and II. The continuous growth of the whole subject should be noted. Theory has particularly progressed through mechanistic studies. Among new types of electrodes, ISFET systems have become important. Among new applications of both solid and liquid membrane electrodes, the fluoride electrode still predominates, closely followed by potassium electrodes. In the field of biological and medical applications, the steady growth is significant. More than 800 papers published between mid-1976 and the end of 1978 are mentioned in the review.     

离子缔合型离子选择电极的研究 I: PVC膜铬(VI)离子选择电极的研制的和应用

A new Cr(VI)-selective electrode of PVC membrane based on triheptyl dodecyl ammonium iodide is described. The response of the electrode is Nernstian for Cr(VI) concentration down to 2X10-6M in 0.03-0.13N HF solution. Limit of detection is 5X10-7M. The plot of logarithms of selectivity coefficients vs. z/γ of various anions is essentially linear with a correlation coefficient of -- 0.88. Applications of the electrode in determination of total Cr in steels and copper alloys, and Cr(VI) in waste-water from chromium electroplating are reported.     

Lead(II) and copper(II) ion-selective electrodes based on two heterocyclic compounds

In this paper, two nitrogen, sulphur or oxygen containing heterocyclic compounds were used as ionophores in ion-selective electrodes. In these two ion-selective electrodes, 2,6-di(5-methyl-1,3,4-oxadiazol-5-yl)pyridine (DMOP) gives the best Pb²⁺ sensitivity and 2,5-di(2′-methylpyridinethio)thiadiazole (DPTD) gives the best sensitivity for Cu²⁺. These electrodes are composed of KTpClPB as anion excluder and DOS as plasticizer. The two membrane electrodes show Nernstian or near-Nernstian response towards Pb²⁺ or Cu²⁺ (29.3 and 27.3 mV/decade, respectively) over the concentration range 10⁻⁵∼10⁻² and 10⁻⁶∼10⁻³ M, respectively. The response time was less than 20 sec and a good reproducibility over a period of 2 months was observed. The electrodes exhibited good selectivities over a number of alkali, alkaline earth and transition metal ions. The proposed electrodes have also been used for the direct determination of Pb²⁺ and Cu²⁺ ions in real samples.     

A mercury(II) ion-selective electrode based on N,N-dimethylformamide-salicylacylhydrazone as a neutral carrier.

A new PVC membrane mercury(II) ion electrode based on N,N-dimethylformamide-salicylacylhydrazone (DMFAS) as an ionophore is described, which shows excellent potentiometric response characteristics and displays a linear log[Hg(2+)] versus EMF response over a wide concentration range between 6.2 x 10(-7) and 8.0 x 10(-2) M with a Nerstian slope of 29.6 mV per decade and a detection limit of 5.0 x 10(-7) M. The response time for the electrode is less than 30 s and the electrode can be used for more than 2 months with less than a 2 mV observed divergence in a potentials. The proposed electrode exhibits very good selectivity for mercury(II) ions over many cations in a wide pH range (pH 1 - 4). The electrode was also applied to the determination of a mercury(II) ion in vegetables and in Azolla filiculoides.     

N,N-bis (2-chloroethyl) amides and N,N-bis(2-chloroethyl) hydrazides of carboxylic acids of the furan series

Reaction of N, N-bis(2-chloroethyl)amine hydrochloride with chloroanhydrides of carboxylic acids of the furan series, in chloroform in the presence of pyridine gives N, N-bis(2-chloroethyl)amides of furan carboxylic acid, furylacrylic acid, 5-nitrofuran carboxylic acid, and 5-nitrofurylacrylic acid.N, N-bis(2-chloroethyl)hydrazides of furan carboxylic acid, furyl carboxylic acid, 5-nitrofuran carboxylic acid, and 5-nitrofurylacrylic acid were obtained in 78–88% yields by reacting N, N-bis(2-chloroethyl)hydrazine hydrochloride with the chloroanhydrides of the appropriate acids in chloroform in the presence of pyridine. The last two hydrazides were prepared in 31 % and 56 % yield, respectively, using anhydrous sodium acetate in place of pyridine.     

A study on the fluoride complexes of plutonium(III), samarium(III) and bismuth(III) using fluoride ion-selective potentiometry

Stability constants of the fluoride complexes of Pu(III), Sm(III) and Bi(III) in 1.0M NaClO₄/HClO₄ medium at 23±1°C have been determined by potentiometry using a fluoride ion-selective electrode. Plutonium was reduced to the trivalent state using quinhydrone with an excess to serve as holding reductant. The log values of concentration stability constants log ₁, log ₂, and log ₃ are 3.58, 6.40 and 12.61 for Pu(III), 3.23, 5.81 and 10.54 for Sm(III) and 3.69, 6.13 and 11.04 for Bi(III), respectively. The log ₂ values in all these cases have very large deviation and may be taken only as rough estimates.