Copper(II) ion-selective microelectrochemical transistor

A device has been developed for the measurement of copper(II) ions (Cu²⁺) in aqueous medium. The device reported here is an electrochemical transistor which consists of two platinum electrodes separated by 100 μm spacing and bridged with an anodically grown film of polycarbazole. Polycarbazole film (undoped form) is observed to be highly selective for the Cu(II) ions. In a completed device, the conductivity of the polycarbazole film changes on addition of Cu(II) ions. The change in conductivity is attributed to the conformational changes in the polymer phase on occupation of the Cu(II) ions, without affecting electron/proton transfer. The device turns on by adding 2.5 × 10⁻⁶ M Cu(II) ions and reaches a saturation region beyond 10⁻⁴ M Cu(II) ion concentrations. In the above concentration range, the device response [I _D vs. log Cu(II) ion concentration] is linear. The selectivity of the device for other metal ions such as Cu(I), Ni(II), Co(II), Fe(II), Fe(III), Zn(II) and Pb(II) is also studied. Received: 6 April 1999 / Accepted: 20 August 1999     

Steady-state and flow-injection response of a metallic silver electrode for potentiometric detection of metal cyanide complex formartion

A metallic silver electrode provides a potentiometric response to Ag(I), Hg(II), Fe(III), Cu(II), Zn(II), Co(II) and Ni(II) ions, and large changes in the electrode potential of up to 400 mV are observed when these ions are injected into a 0.29 mM soulution of cyanide ion. Injection 10-μl aliquots into a reagent stream with a cyanide concentration of 0.1 mM is shown to give the expected sigmoidal-shaped response curve for peak height as a function of metal ion concentration. Sub-nanomole quantities of metal ions are detectable with a peak height of ca. 20 mV, depending on the cyanide concentration.     

Reactivity of M(II) metal-substituted derivatives of pig purple acid phosphatase (uteroferrin) with phosphate

The Fe(II) of the binuclear Fe(II)Fe(III) active site of pig purple acid phosphatase (uteroferrin) has been replaced in turn by five M(II) ions (Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)). An uptake of 1 equiv of M(II) is observed in all cases except that of Cu(II), when a second more loosely bound Cu(II) is removed by treatment with edta. The products have been characterized by different analytical procedures and by UV-vis spectrophotometry. At 25 degrees C, I = 0.100 M (NaCl), the nonenzymatic reactions with H(2)PO(4)(-) give the mu-phosphato product, and formation constants K/M(-1) show an 8-fold spread at pH 4.9 of 740 (Mn), 165 (Fe), 190 (Co), 90 (Ni), 800 (Cu), 380 (Zn). The variations in K correlate well with stability constants for the complexing of H(2)PO(4)(-) and (CH(3)O)HPO(3)(-) with M(II) hexaaqua ions. At pH 4.9 with [H(2)PO(4)(-)] > or = 3.5 mM rate constants k(obs) decrease, and an inhibition process in which a second [H(2)PO(4)(-)] coordinates to the dinuclear center is proposed. The mechanism considered accounts for most but not all of the features displayed. Thus K(1) values for the coordination of phosphate to M(II) are in the range10-60 M(-1), whereas K(2) values for the bridging of the phosphate to Fe(III) are in the narrower range 7.8-12.4. From the fits described K(i) approximately 10(3) M(-1) for the inhibition step, which is independent of the identity of M(II). Values of k(obs) decrease with increasing pH, giving pK(a) values which are close to 3.8 and independent of M(II) (Fe(II), Zn(II), Mn(II)). The acid dissociation process is assigned to Fe(III)-OH(2) to Fe(III)-OH(-), where OH(-) is less readily displaced by phosphate.     

Influence and role of metal ions in enzymatic catalysis with e.c. 1.2.3.2. xanthine oxidase Application to trace analysis

The effect of metal ions on the reductive half-reaction of xanthine oxidase (XOD) in the catalytic conversion of xanthine into uric acid has been studied spectrophotometrically in Tris-HCl buffer at pH 7.4, 37 +/- 0.1 degrees and ionic strength 0.04M. Some metal ions display inhibitor properties, the sequence of inhibiting efficiency being Ag(I) > Hg(II) > Cu(II) > Cr(VI) > V(V) > Au(III) > Tl(I) and for these the I(50) values were determined. Only Tl(I), V(V) and Cu(II) showed reversible inhibition and therefore for these the mechanisms were assessed [competitive for V(V) and Tl(I); uncompetitive for Cu(II)]. The conditional inhibition constants (K(i)) were also determined. The effect of EDTA for protection of the enzyme against metal inhibition, and for its reactivation after inhibition, was also investigated. Utilization of the linear relationship between relative enzyme activity and inhibitor concentration allowed sensitive and selective (though not specific) determination of Ag(I) and Hg(II) (10(-9)-10(-8)M), and of Cu(II) and Cr(VI) (10(-7)-10(-6)M), the maximum relative error being +/- 4%. For a few metal ions, e.g., Ag(I) and Cr(VI), in the presence of EDTA, a certain specificity is observed.     

Luminol-K2S2O8体系中金属离子化学发光行为的研究

报导了在自行设计的流动注射式化学发光分析仪上,对Luminal-K2S2O8体系中32种金属离子的化学发光行为的系统研究.确定了对金属离子的最优测定条件以及大多数金属离子的检出极限和线性范围.     

Synthesis, characterization and applications of pyrocatechol modified amberlite XAD-2 resin for preconcentration and determination of metal ions in water samples by flame atomic absorption spectrometry (FAAS)

A new chelating resin is prepared by coupling Amberlite XAD-2 with pyrocatechol through an azo spacer, characterized (by elemental analysis, IR and TGA) and studied for preconcentrating Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Zn(II) using flame atomic absorption spectrometry (FAAS) for metal monitoring. The sorption is quantitative in the pH range 3.0-6.5, whereas quantitative desorption occurs instantaneously with 2 M HCl or HNO(3) The sorption capacity has been found to be in the range 0.023-0.092 mmol g(-1) of resin. The loading half time (t(1/2)) is 1.4, 4.8, 1.6, 3.2, 2.3 and 1.8 min, respectively for Cd, Co, Cu, Fe, Ni and Zn. The tolerance limits of electrolytes NaCl, NaBr, NaNO(3), Na(2)SO(4) and Na(3)PO(4) in the sorption of all the six metal ions (0.2 mug ml(-1)) are reported. The Mg(II) and Ca(II) are tolerable with each of them (0.2 mug ml(-1)) up to a concentration level of 0.01-1.0 M. The enrichment factor has been found to be 200 except for Fe and Cu for which the values are 80 and 100, respectively. The lowest concentration of metal ion for quantitative recovery is 5, 10, 20, 25, 10 and 10 mug l(-1) for Cd, Co, Cu, Fe, Ni and Zn, respectively. The simultaneous determination of all these metal ions is possible and the method has been applied to determine all the six metal ions in tap and river water samples (RSD相似文献   

Effects of transition metal ion coordination on the collision-induced dissociation of polyalanines

Transition metal-polyalanine complexes were analyzed in a high-capacity quadrupole ion trap after electrospray ionization. Polyalanines have no polar amino acid side chains to coordinate metal ions, thus allowing the effects metal ion interaction with the peptide backbone to be explored. Positive mode mass spectra produced from peptides mixed with salts of the first row transition metals Cr(III), Fe(II), Fe(III), Co(II), Ni(II), Cu(I), and Cu(II) yield singly and doubly charged metallated ions. These precursor ions undergo collision-induced dissociation (CID) to give almost exclusively metallated N-terminal product ions whose types and relative abundances depend on the identity of the transition metal. For example, Cr(III)-cationized peptides yield CID spectra that are complex and have several neutral losses, whereas Fe(III)-cationized peptides dissociate to give intense non-metallated products. The addition of Cu(II) shows the most promise for sequencing. Spectra obtained from the CID of singly and doubly charged Cu-heptaalanine ions, [M + Cu - H](+) and [M + Cu](2+) , are complimentary and together provide cleavage at every residue and no neutral losses. (This contrasts with [M + H](+) of heptaalanine, where CID does not provide backbone ions to sequence the first three residues.) Transition metal cationization produces abundant metallated a-ions by CID, unlike protonated peptides that produce primarily b- and y-ions. The prominence of metallated a-ions is interesting because they do not always form from b-ions. Tandem mass spectrometry on metallated (Met = metal) a- and b-ions indicate that [b(n) + Met - H](2+) lose CO to form [a(n) + Met - H](2+), mimicking protonated structures. In contrast, [a(n) + Met - H](2+) eliminate an amino acid residue to form [a(n-1) + Met - H](2+), which may be useful in sequencing.     

Hydrothermal syntheses,crystal structures,and properties of two-dimensional homo- and heterometallic cyanide-bridged complexes: [Cu2(CN)2(bpym)] and [Fe(bipy)2(CN)4Cu2] (bpym = 2,2'-bipyrimidine,bipy = 2,2'-bipyridine)

The hydrothermal reaction of K(3)[Fe(CN)(6)], CuCl(2), and 2,2'-bipyridine (bipy) resulted in the formation of a 2D cyanide-bridged heterobimetallic Fe(II)-Cu(I) complex, [Fe(bipy)(2)(CN)(4)Cu(2)], 1. Working in the same conditions, but using 2,2'-bipyrimidine (bpym) instead of bipy and methanol as solvent, we obtained the homometallic Cu(I) complex [Cu(2)(CN)(2)(bpym)](2), 2. The structure of 1 consists of cyanide-bridged Fe(II)-Cu(I) layers, constructed from alternately fused 6 (Fe(2)Cu(4)) and 10 (Fe(2)Cu(8)) metal-membered centrosymmetric rings, in which copper(I) and iron(II) ions exhibit distorted trigonal planar and octahedral cooordination environments, respectively. The formation of 1 can be explained by assuming that, under high pressure and temperature, iron(III) and copper(II) ions are reduced with the simultaneous and/or subsequent substitution of four cyanide ligands by two bipy molecules in the ferricyanide anions. It is interesting to note that 1 is the first cyanide-bridged heterobimetallic complex prepared by solvothermal methods. The structure of 2 consists of neutral 2D honeycomb layers constructed from fused Cu(6)(CN)(4)(bpym)(2) rings, in which copper(I) atoms exhibit distorted tetrahedral geometry. The isolation of 1 and 2, by using K(3)[Fe(CN)(6)] as starting material, demonstrates that hydrothermal chemistry can be used not only to prepare homometallic materials but also to prepare cyanide-bridged bimetallic materials. The temperature dependence of chi(M)T and M?ssbauer measurements for 1 reveal the existence of a high spin <--> low spin equilibrium involving the Fe(II) ions.     

Preparation, characterization and application of an cellulose ion-exchanger with acetoacetamide functional groups

Summary A method is described for functionalizing acetoacetamide chelating groups onto microcrystalline cellulose (Cell-AcAc). This material shows a significant affinity for Fe(III), Cu(II) and U(VI) and no or very less affinity for the M(I) ions (M=Na, K), M(II) ions (M= Mg, Ca; Fe, Co, Ni, Zn), La(III) and Y(III) including Th(IV). The obtained K _d values offer a column separation method for U(VI) ions from the rest of above-mentioned metal ions except Fe(III). Cell-AcAc and its Cu(II) complexes are characterized by means of FT-IR spectra.

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Darstellung, Charakterisierung und Anwendung von Ionenaustauschmaterial aus Cellulose mit chemisch gebundener Acetoacetamid-Gruppe

Zusammenfassung Die Darstellung von immobilisiertem Acetoacetamid auf mikrokristallinem Cellulosepulver (Cell-AcAc) wird beschrieben. Der Ionenaustauscher Cell-AcAc hat eine ausgeprägte Affinität für Fe(III), Cu(II) and U(VI), aber nahezu keine für die M(I)-Ionen (M=Na, K) M(II)-Ionen (M=Mg, Ca; Fe, Co, Ni, Zn), La(III), Y(III) sowie Th(IV). Die erhaltenen K _d-Werte ermöglichen für U(VI)-Ionen eine quantitative säulen-chromatographische Trennung von den anderen genannten Kationen mit Ausnahme von Fe(III). Das Ionenaustauschmaterial Cell-AcAc und sein Cu(II)-Komplex wurden durch FT-IR-Spektren charakterisiert.

     

Ion flotation behaviour of thirty-one metal ions in mixed hydrochloric/nitric acid solutions

The ion flotation of 31 metal ions in hydrochloric/nitric acid solution with the cationic surfactant cetylpyridinium chloride was investigated. A 25-ml portion of 0.27-2.87 x 10(-4)M metal ion and 1.8-6.0 x 10(-4)M cetylpyridinium chloride solution in 0.17-3.4M acid mixture ([HCl]:[HNO(3)] = 2.4:1) was subjected to flotation in a cell, 22.5 cm high and 4.0 cm in diameter, for 5 min, with nitrogen bubbles. Ir(IV), Pt(IV), Ge(IV), Sn(IV), Bi(III), Au(III), Tl(III), Pd(II) and Sn(II) were floated from solution in 95-100% yield; Ru(III), Rh(III), Ir(III), Hg(II), Ag(I) and Tl(I) were partly floated, while Cr(VI), Ti(IV), Zr(IV), Ga(III), In(III), Fe(III), Sb(III), Al(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), CD(II) and Pb(II) were floated with less than 20% yield. The flotation behaviour of these metal ions in the mixed acid system was compared with that in hydrochloric acid. The flotation is more efficient in the mixed acid system.     

Effects of Metal Ions on the Micellization of Ionic Surfactants

The effect of metal ions (Cu(II), Zn(II), Co(II), Ni(II), La(III), Fe(III)) on the critical micelle concentration (CMC) of ionic surfactants (sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB)) were investigated at 25±0.1°C, μ = 0.1 M (KNO₃), using conductivity method in this paper. A series of general empirical expressions about the relationship between the CMC values for SDS and CTAB and the concentrations of metal ions have been derived. The results showed that the CMC values for both SDS and CTAB decreased with increasing the concentrations of metal ions. This can be interpreted by the counterion effect and the entropy driving effect.     

Approach combining on-line metal exchange and tangential-flow ultrafiltration for in-situ characterization of metal species in humic hydrocolloids

This paper deals with the development and optimization of an analytical procedure using ultrafiltration and a flow-injection system, and its application in in-situ experiments to characterize the lability and availability of metal species in humic-rich hydrocolloids. The on-line system consists of a tangential flow ultrafiltration device equipped with a 3-kDa filtration membrane. The concentration of free ions in the filtrate was determined by atomic-absorption spectrometry, assuming that metals not complexed by aquatic humic substances (AHS) were separated from the complexed species (M–AHS) retained by the membrane. For optimization, exchange experiments using Cu(II) solutions and AHS solutions doped with the metal ions Ni(II), Mn(II), Fe(III), Cd(II), and Zn(II) were carried out to characterize the stability of the metal–AHS complexes. The new procedure was then applied in-situ at a tributary of the Ribeira do Iguape river (Iguape, São Paulo State, Brazil) and evaluated using the ions Fe(III) and Mn(II), which are considered to be essential constituents of aquatic systems. From the exchange between metal–natural organic matter (M–NOM) and the Cu(II) ions it was concluded that Cu(II) concentrations >485 μg L^?1 were necessary to obtain maximum exchange of the complexes Mn–NOM and Fe–NOM, corresponding to 100% Mn and 8% Fe. Moreover, the new analytical procedure is simple and opens up new perspectives for understanding the complexation, transport, stability, and lability of metal species in humic-rich aquatic environments.     

Lead ion-selective electrodes based on polyphenylenediamine as unique solid ionophores

A novel membrane electrode for Pb(II) ion detection based on semi-conducting poly(m-phenylenediamine) microparticles as a unique solid ionophore was fabricated. The electrode exhibited significantly enhanced response towards Pb(II) over the concentration range from 3.16 × 10⁻⁶ to 0.0316 M at pH 3.0-5.0 with a low detection limit of 6.31 × 10⁻⁷ M, a high sensitivity displaying a near-Nernstian slope of 29.8 mV decade⁻¹ for Pb(II). The electrode showed a long lifetime of 5 months and a short response time of 14 s. A systematical investigation on the effect of anion excluder and various foreign ions on the selectivity of the electrode by a fixed interference method suggests that all other metal ions hardly ever interfere with the determination of Pb(II) except high concentration Hg(II). The electrode was successfully used as an indicator electrode in the potentiometric titration of Pb(II) with EDTA. Furthermore, the electrode has been used to satisfactorily analyze four types of real-world samples like spiked human urine, spiked tap water, and river water containing interfering ions like Na(I), Ca(II), Mg(II), Zn(II), Pd(II), Fe(III), K(I), Cu(II) and Hg(II) up to 8.04 × 10⁻⁴ M, demonstrating fast response, high selectivity, good recovery (96.6-121.4%), good repeatability (RSD 0.31-6.45%), and small relative error (5.0%).     

Determination of platinum(IV) by UV spectrophotometry

A simple, rapid and sensitive spectrophotometric procedure for the determination of platinum has been elaborated. Pt traces were determined in the form of the PtCl(6)(2-) complex in hydrochloric acid solution whose concentration varies from 0.01 to 2 mol L(-1) by measuring the absorbance at 260 nm. The detection limit is 4.7 x 10(-7) mol L(-1), the linearity range from 2 x 10(-6) mol L(-1) to 7 x 10(-6) mol L(-1), and the correlation coefficient is r=0.9990. No significant interferences were observed from a majority of the investigated ions, such as Zn(II), Pb(II), Mn(II), Cd(II), Co(II) and Ni(II) with the exception of Cu(II), Sb(III), Fe(III), Pd(II), Sn(II) and I(-) ions. The method was successfully applied for the determination of Pt traces in different solid samples and the recovery from inorganic materials was studied.     

Coated-wire silver ion-selective electrode based on silver complex of cyclam.

A coated-wire ion-selective electrode (ISE) based on cyclam (1,4,8,11-tetraazacyclotetradecane) as a neutral carrier in a polyvinyl chloride (PVC) matrix was fabricated for the determination of Ag(I) ions. The coated-wire ISE exhibited a linear Nernstian response over the range 1 x 10(-1) to 1 x 10(-7) M with a slope of 59 +/- 2 mV per decade change and a detection limit of 5 x 10(-8) M. The ISE shows a greater preference for Ag over other cations with good precision. The electrode was selective towards Ag(I) ions in the presence of 13 different metal ions tested. The selectivity coefficients (K(ij)) were determined for Na(I), K(I), Mg(II), Ca(II), Ba(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Hg(II). The selectivity coefficients of these cations are in the range of 10(-4) to 10(-2). This ISE was used for the determination of free silver and total silver in electroplating bath solutions, additives and brighteners.     

Analytical utility of coupled transport across a supported liquid membrane Selective preconcentration of zinc

A liquid membrane comprising 5-10% bis(2,4,4-trimethylpentyl)phosphinic acid in dodecane that is supported between an aqueous sample at pH 4.7-6.0 and a 0.1M HCl receiver results in uphill transport of Zn(II) from the sample into the receiver. With 2 ml of receiver, a 5 cm(2) membrane and 60 min dialysis time, Zn(II) is preconcentrated by a factor of ca. 13 when the initial concentration in the sample is in the range 1.5 x 10(-7)-1.5 x 10(-4)M. The enrichment factor is directly proportional to time up to 30 min since the transport rate of Zn(II) across the membrane is constant over this period. At longer times the flux is slowed as the system begins to approach equilibrium. The presence of other metals such as Cu(II), Co(II), Ni(II), Cd(II), Pb(II) and Fe(II) does not change the enrichment factor for Zn(II), even when the interferent is at a concentration high enough for the rate of transport (nmole/min) of the interferent and Zn(II) to be about the same. The flux of Zn(II) was about 40 times that of Cu(II) and 100 times that of Co(II) when their concentrations in the sample were equal. The other metal ions examined are not significantly transported.     

Copper in Acid Chloride Solutions: Electrochemical Behavior by Quartz Microgravimetry and Voltammetry

The cathodic deposition of copper on a gold electrode and its subsequent anodic dissolution in an acid chloride solution, where two successive stages of a one-electron transfer are distinguishable because of the stability of chloride complexes of Cu(I), is studied by voltammetry and quartz microgravimetry. The formation of a film of an intermediate compound of Cu(I) during the deposition and dissolution of copper is revealed experimentally. Techniques for identifying the intermediate solid species are suggested. During a cathodic polarization, a film of intermediate compound CuCl forms at a reduced concentration of chloride ions in the Cu(II)/Cu(I) process, while during the anodic dissolution of the copper deposit formed during the cathodic polarization the intermediates appear in the Cu(0)/Cu(I) process, the concentration of chloride ions notwithstanding. The change in the electrochemical behavior of the system caused by a decrease in the concentration of chloride ions is explained.     

Separation and determination of trace amounts of beryllium(II), aluminium(III) and chromium(III) with chromotrope 2C chelates by RP-HPLC

A reversed-phase high-performance liquid chromatographic separation and determination of beryllium(II), aluminium(III) and chromium(III) with chromotrope 2C chelates on a C18-bonded stationary phase is reported. Methanol-water (45:55 v/v) containing 6 x 10(-3)M tetra-n-butylammonium bromide (TBAB) and 2 x 10(-2)M acetate buffer solution (pH 6.0) as mobile phase and with spectrophotometric detection at 530 nm was applied. The method has high sensitivity, the detection limits being 0.2 ppb for beryllium(I), 1 ppb for aluminium(III) and 2 ppb for chromium(III). Under the optimum conditions, most other metal ions did not interfere, e.g. up to 2 mg of Hg(II), Sn(II, IV), Pb(II), Bi(III), Ag(I), Zn(II), Cd(II), Cu(II), 1.5 mg of Fe(II), Co(II), Ni(II), 1.2 mg of Ca(II), Mg(II), Sr(II), Ba(II), 1 mg of Ga(III), In(III), 0.5 mg of Fe(III), 1 mg of Ga(III), In(III), 0.5 mg of Fe(III), 0.4 mg of Th(IV), Zr(IV). The method can be applied to the simultaneous determination of trace amounts of beryllium(II), aluminium(III) and chromium(III), in water, rice, flour and human hair samples.     

Synthesis and magnetic properties of heterometal cyclic tetranuclear complexes [Cu(II)LM(II)(hfac)]2 (M(II) = Zn,Cu, Ni,Co, Fe,Mn; H3L = 1-(2-hydroxybenzamido)-2-((2-hydroxy-3-methoxybenzylidene)amino)ethane; Hhfac = hexafluoroacetylacetone)

A series of heterometal cyclic tetranuclear complexes [Cu(II)LM(II)(hfac)](2) (M(II) = Zn (1), Cu (2), Ni (3), Co (4), Fe(5), and Mn (6)) have been synthesized by the assembly reaction of K[CuL] and [M(II)(hfac)(2)(H(2)O)(2)] with a 1:1 mole ratio in methanol, where H(3)L = 1-(2-hydroxybenzamido)-2-((2-hydroxy-3-methoxybenzylidene)amino)ethane and Hhfac = hexafluoroacetylacetone. The crystal structures of 2, 4, and [Cu(II)LMn(II)(acac)](2) (6a) (Hacac = acetylacetone) were determined by single-crystal X-ray analyses. Each complex has a cyclic tetranuclear Cu(II)(2)M(II)(2) structure, in which the Cu(II) complex functions as a "bridging ligand complex", and the Cu(II) and M(II) ions are alternately arrayed. One side of the planar Cu(II) complex coordinates to one M(II) ion at the two phenoxo and the methoxy oxygen atoms, and the opposite side of the Cu(II) complex coordinates to another M(II) ion at the amido oxygen atom. The temperature-dependent magnetic susceptibilities revealed spin states of S(M) = 0, 1/2, 1, 3/2, 2, and 5/2 for the Zn(II), Cu(II), Ni(II), Co(II), Fe(II), and Mn(II) ions, respectively. Satisfactory fittings to the observed magnetic susceptibility data were obtained by assuming a rectangular arrangement with two different g-factors for the Cu(II) and M(II) ions, two different isotropic magnetic exchange interactions, J(1) and J(2), between the Cu(II) and M(II) ions, and a zero-field splitting term for the M(II) ion. In all cases, the antiferromagnetic coupling constants were found for both exchange interactions suggesting nonzero spin ground states with S(T) = 2/S(M) - S(Cu)/, which were confirmed by the analysis of the field-dependent magnetization measurements.     

Liquid-state mercury(II) ion-selective electrode based on N-(O,O-diisopropylthiophosphoryl)thiobenzamide

A liquid ion-exchange electrode containing a complex of mercury(II) with N-(O,O-diisopropylthiophosphoryl)thiobenzamide in carbon tetrachloride is described. The electrode shows excellent sensitivity and good selectivity. The slope of the calibration graph is 29.0 mV/pHg²⁺ in the pHg²⁺ in the pHg²⁺ range 2–15.2 in mercury(II) ion buffers. The electrode can be used for determination of 5 × 10^?5–10^?2 M Hg(II) in the presence of 10^?2 M Cu(II), Ni(II), Co(II), Zn(II), Pb(II), Cd(II), Mn(II), Fe(III), Cr(III), Bi(III) or Al(III) ions and in the presence of 10^?3 M Ag(I) ions. It can bealso used for end-point detection in titrations with EDTA of 10^?3–10^?4 M mercury(II) at pH 2.