Novel Membrane Potentiometric Thiocyanate Sensor Based on Tribenzyltin(IV) Dithiocarbamate

A novel PVC membrane ion‐selective electrode based on tribenzyltin(IV) dithiocarbamate [Sn(IV)–TBDTB] as neutral carrier was developed for thiocyanate (SCN^?) determination. The electrode exhibits a near‐Nernstian response for SCN^? with a slope of 62.8±2.0 mV per decade over a wide concentration range 1.0×10^?1–2.0×10^?6 mol L^?1 and a detection limit of 1.0×10^?6 mol L^?1 in MES–NaOH buffer, pH 6.0, at 25 °C. The electrode prepared with 1.5 wt.% Sn(IV)–TBDTB, 32.5 wt.% PVC and 66.0 wt.% 2‐nitrophenyloctyl ether (o‐NPOE) shows optimal response characteristics. Anti‐Hofmeister selectivity sequence for a series of anions shown by the electrode was as follows: SCN^?>Sal^?>I^?>ClO >phCOO^?>CH₃COO^?>Br^?>Cl^?>NO >NO >Citrate>SO₄^2?. The useful pH range for the electrode was found to be 3–7 with a response time 30–40 s. The electrode has been used for direct determination of thiocyanate in wastewater with satisfactory results.     

Zn(II)‐Selective Membrane Electrode Based on Tetraazamacrocycle [Bzo2Me2Ph2(16)hexaeneN4]

A PVC membrane electrode using [Bzo₂Me₂Ph₂(16)hexaeneN₄] ( I ) as ionophore, oleic acid as lipophilic additive and o‐nitrophenyloctyl ether as plasticizer has been investigated as Zn(II)‐selective electrode. The membrane incorporating 34.9% (w/w) PVC, 2.3% I , 4.7% OA and 58.1% o‐NPOE gave linear response over the concentration range 2.82×10^?6?1.0×10^?1 M with a Nernstian slope of 28.5±0.2 mV/decade of concentration with a detection limit of 2.24×10^?6 M (0.146 ppm) and showed a response time of less than 10 s and could be used in pH range 2.5–8.5. High selectivity was obtained over a wide variety of metal ions. The proposed electrode was successfully used as an indicator electrode in potentiometric titration of zinc ions with EDTA and for determination of zinc in real samples.     

Comparative Study of Lead(II) Selective Poly(vinyl chloride) Membrane Electrodes Based on Podand Derivatives as Ionophores

The two podand chelates based on diethylsulfide, 1,5‐bis(2′‐hydroxy‐4′‐nitrophenoxy)‐3‐thiapentane (L₁) and 1,5‐bis(8′‐oxybenzopyridine)‐3‐thia pentane (L₂), have been synthesized and explored as neutral ionophores for preparing poly(vinyl chloride) based membrane electrodes selective to Pb²⁺. The addition of anionic additives and various plasticizers has been found to substantially improve the performance of the electrode. The best performance was obtained with the electrode No. 1 having a membrane of ionophore (L₁) with the composition PVC:o‐NPOE:ionophore (L₁):NaTFPB (%w/w) of 33 : 62 : 3 : 2. The electrode exhibits Nernstian response with a slope of 31.57±0.3 mV decade^?1 of activity in the concentration range from 2.0×10^?9 to 1.0×10^?1 M Pb²⁺, performs satisfactorily over a wide pH range (1.6–7.0), with a fast response time (5 s).     

Selective Determination of Zn2+ Ion in Various Environmental,Biological and Medicinal Plant Samples Using a Novel Coated Graphite Electrode

Novel Zn²⁺ ion‐selective PVC based coated graphite electrodes were fabricated using the ionophores N‐((1H‐indol‐3‐yl)methylene)thiazol‐2‐amine (I₁), N‐((1H‐indol‐3‐yl)methyl)‐thiazol‐2‐amine (I₂) and 1‐((1H‐indol‐3‐yl)methylene)urea (I₃). Their potentiometric performance was examined in dependence of the addition of plasticizers and anion excluders and compared. It is found that the coated graphite electrode with the composition I₁:KTpClPB:o‐NPOE:PVC=9 : 1.5 : 51 : 38.5 is the best with respect to the wide working concentration range (4.2×10^?8–1.0×10^?1 mol L^?1), low detection limit (1.6×10^?8 mol L^?1) and wide pH range of 3.0–8.0. The proposed electrode was successfully applied to quantify Zn²⁺ in various environmental, biological and medicinal plant samples and used as indicator electrode.     

Nickel Pyrazolyl Borate Complex: Synthesis,Structure, and Analytical Application as Benzoate Selective Sensor

The complex [Tp^Ph,MeNi(Cl)Pz^Ph,MeH] ( I ) [Tp^Ph,Me=hydrotris(3‐phenyl‐5‐methyl‐pyrazol‐1‐yl)borate; Pz^Ph,MeH=3‐phenyl‐5‐methyl‐pyrazole] has been synthesized and explored as ionophore for the preparation of a poly(vinyl chloride) (PVC) membrane sensor for benzoate anions. The formation constants for the interaction of complex I with different organic/inorganic anions in solution have also been studied by sandwich membrane method. PVC based membranes of I using tridodecylmethylammonium chloride (TDDMACl) as cation discriminator and o‐nitrophenyloctyl ether (o‐NPOE), dibutylphthalate (DBP), benzylacetate (BA) and tributylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as benzoate selective sensors. The best performance was shown by the membrane with composition (w/w) of I (5): PVC (150): NPOE (345): TDDMACl (0.3). The proposed sensor exhibits significantly enhanced selectivity toward benzoate ions over the concentration range 2.2×10^?6–1.0×10^?1 M with a lower detection limit of 1.4×10^?6 M and a Nernstian slope of 59.2 mVdecade^?1 of activity within a pH range of 4.5–8.5. The sensor has a response time of 12 s and can be used for at least 8 weeks without any considerable divergence in their potential response. The membrane sensor of complex I have been checked for reversible and accurate sensing of benzoate levels present in liquid food products.     

基于酞菁铜衍生物为载体的电极对水杨酸根的选择性电位响应

本文以2,9,16,23-四硝基酞菁铜(II) (Cu(II)TNPc) 和2,9,16,23-四氨基酞菁铜(II) (Cu(II)TAPc) 为载体制备PVC聚合膜,构建了水杨酸根选择性电极,并探讨了该电极的选择性响应性能。研究了增塑剂的性质、载体的含量及阴、阳离子添加剂对电极电位响应的影响。结果表明,基于Cu(II)TNPc为载体的PVC膜电极对水杨酸根 (Sal－) 呈现出优先选择性电位响应。具有最佳电位响应的电极的膜组成是：(w/w) 3.0% Cu(II)TNPc,67.0% o-NPOE,29.5% PVC和0.5% NaTPB。基于该组成的电极的线性响应范围为1.0×10－1－9.0×10－7 mol·L－1,检测下限为7.2×10－7 mol·L-1,斜率为－59.8±0.5 mV/decade;其响应快速,稳定性好,适宜的pH范围是3.0－7.0。并成功运用于了实际样品中水杨酸含量的测定,获得令人满意的结果。     

Highly Selective Thiocyanate Electrode Based on Bis‐bebzion Schiff Base Binuclear Copper(II) Complex as Neutral Carrier

Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN^?) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN^?>ClO₄ ^?>Sal^? > I^?>NO₃ ^?>Br^?> Cl^?>NO₂ ^?>SO₃ ^2?>F^?>H₂PO₄ ^?>SO₄ ^2?. The electrode exhibited near‐Nernst response for SCN^? with a slope of –59.0 mV/decade over a wide concentration range (8.5×10^?7～6.8×10^?1 mol/L) with a detection limit of –5.0×10^?7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].     

Use of Tin (IV) Porhyrins as Ionophores for the Construction of Phthalate‐Selective Electrodes: Influence of the Structure and Membrane Composition on their Response Properties

Tin(IV) porphyrins derivatives were used as ionophores for phthalate selective electrodes preparation. The influence of ionophore structure and membrane composition (amount of incorporated ionic sites) on the electrode response, selectivity and long‐term stability were studied. Poly(vinyl chloride) polymeric membranes plasticized with o‐NPOE (o‐nitrophenyloctylether) and containing Sn(IV)‐tetraphenylporphyrin (TPP) dichloride (Sn(IV)[TPP]Cl₂) or Sn(IV)‐octaethylporphyrin (OEP) dichloride (Sn(IV)[OEP]Cl₂), and in some cases incorporating lipophilic cationic (tetraocthylammonium bromide ‐ TOABr) and anionic (sodium tetraphenylborate – NaTPB and potassium tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate‐KTFPB) additives, were prepared and their potentiometric characteristics compared. Both ionophores are shown to operate via a neutral mechanism, and the addition of 10 mol % of lipophilic quaternary ammonium salt derivative to the membrane is required to achieve optimal electrode performance. The potentiometric units prepared, with Sn(IV)[TPP]Cl₂ (Type A) or Sn(IV)[OEP]Cl₂ (Type B) without additives, presented a slope of ?52.8 mV dec^?1 and ?58.8 mV dec^?1 and LLLR of 9.9×10^?5 mol L^?1 and 9.9×10^?6 mol L^?1, respectively. The units prepared using the same metalloporphyrins and incorporating 10% mol TOABr presented a slope of ?55.0 mV dec^?1 and ?57.8 mV dec^?1 and LLLR of 5.0×10^?7 mol L^?1 and 3.0×10^?7 mol L^?1. Their analytical usefulness was assessed by potentiometric determinations of phthalate in water and industrial products providing results that presented recoveries of about 100%.     

A Coated Graphite Thorium‐Ion Selective Potentiometric Sensor Based on a Calix[4]arene Bearing Phosphoryl Groups

5,11,17,23‐Tetra‐tert‐butyl‐25,26,27,28‐tetrakis(diphenylphosphinoylmethoxy)calix[4]arene ( 1 )has been used for the preparation of a graphite coated thorium ion‐selective electrode (Th⁴⁺‐ISE). The plasticized PVC membrane containing 30% PVC, 58% ortho‐nitrophenyloctylether (NPOE), 4% sodium tetraphenylborate (NaTPB) and 8% ionophore was directly coated on a graphite rod. This sensor gave good Nernstian responses with a slope of 15.5 ± 0.1 mV/decade over a concentration range of 1 × 10^?5 ?1 × 10^?3 M of thorium ions with a limit of detection of 7.9 × 10^?6 M. The dynamic response time of the electrode to achieve a steady potential was found to be about 15 seconds. The potential of the prepared sensor was independent of the pH variation in the range 2.3–4.0. The selectivity relative to several mono‐, di‐ and tri‐valent metal ions, i.e. Li⁺, Na⁺, K⁺, Ag⁺, NH₄⁺, Sr²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, La³⁺, Sm³⁺, Dy³⁺, Er³⁺ and Y³⁺ was examined. This electrode can be used for 6 months without any considerable divergences in the potential response. The sensor was successfully used as an indicator electrode for the potentiometric titration of a thorium solution using a standard solution of EDTA.     

Tripodal Cadmium Complex and Macrocyclic Ligand Based Sensors for Phosphate Ion Determination in Environmental Samples

Tripodal cadmium complex of hydrotris(3‐phenyl‐5‐methylpyrazolyl)borate (I₁) and macrocyclic ligand 5,7 : 12,14 : 19,21 : 26,28‐Bzo₄‐[28]‐5,13,19,27‐tetraene‐8,11,22,25‐N_4–1,4,15,18‐O₄ (I₂), have been synthesized and characterized by IR, ¹H NMR, Mass and elemental analysis. Spectroscopic investigations indicate high affinity of these receptors for dihydrogen phosphate ion. Polyvinyl chloride (PVC) based membranes of (I₁) and (I₂) using hexadecyl trimethylammonium bromide (HTAB) as cation discriminator and dibutylpthalate (DBP), tributyl phosphate (TBP), dioctylsebacate (DOS), and o‐nitrophenyloctyl ether (o‐NPOE), as plasticizing solvent mediators were prepared and investigated as H₂PO selective sensors. The best performance was shown by the membrane of composition (w/w) (I₂) (5%):PVC (31%) : DBP (61.5%):HTAB (2.5%). This sensor works well over a wide concentration range 2.1×10^?7 to 1.0×10^?2 M with Nernstian compliance (59.0 mV decade^?1 of activity) with a fast response time of 14 s and showed good selectivity for dihydrogen phosphate ion over a number of anions. The sensor exhibits good reproducibility (SD±0.3 mV) and could be used successfully for the determination of phosphate in soil water samples.     

Highly Thiocyanate‐Selective PVC Membrane Electrode Based on Lipophilic Ferrocene Derivative

A novel anion‐selective PVC membrane electrode based on bis‐[(3‐ferrocenyl)‐(2‐crotonic acid)] copper(II) complex [Cu(II)‐BFCA] as neutral carrier is described, which demonstrates excellent potentiometric response characteristics toward thiocyanate ion and anti‐Hofmeister selectivity sequence in following order: SCN^?>I^?>ClO >Sal^?>Br^?>NO >Cl^?≈NO >SO >SO . The electrode shows a near‐Nernstian response for thiocyanate ion in a wide range of 9.0×10^?7–1.0×10^?1 M with a detection limit 6.8×10^?7 M and a slope of ?59.1 mV/decade in pH 5.0 of phosphate buffer solution at 20 °C. The influences of lipophilic cationic and anionic additives on the response properties of the electrode were investigated. High sensitivity and wide linear dynamic range were observed for the electrode in the presence of hexadecyltrimethylammoniumborate (HTAB) as a lipophilic cationic additive. The electrode was successfully applied to the determination of thiocyanate ion in waste water and human saliva.     

Comparative Studies of Tridentate Sulfur and Nitrogen‐Containing Ligands as Ionophores for Construction of Cadmium Ion‐Selective Membrane Sensors

New polymeric membrane cadmium‐ion selective sensors have been prepared by incorporating nitrogen and sulfur containing tridentate ligands as the ionophores into the plasticized PVC membranes. Poly(vinyl chloride) (PVC) based membranes of potassium hydrotris[N‐(2,6‐xylyl)thioimdazolyl) borate] (KTt^2,6‐xylyl) and potassium hydrotris(3‐phenyl‐5‐methylpyrazolyl) borate (KTp^Ph,Me) with sodium tetraphenyl borate (NaTPB) as an anionic excluder and dibutylphthalate (DBP), tributylphthalate (TBP), dioctylsebacate (DOS), and o‐nitrophenyloctyl ether (o‐NPOE) as plasticizing solvent mediators were investigated in different compositions. KTt^2,6‐xylyl was found to be a selective and sensitive ion carrier for Cd(II) membrane sensor. A membrane composed of KTt^2,6‐xylyl:NaTPB:PVC:DBP with the % mole ratio 2.3 : 1.1 : 34.8 : 61.8 (w/w) works well over a very wide concentration range (7.8×10^?8–1.0×10^?2 M) with a Nernstian slope of 29.4±0.2 mV/decades of activity between pH values of 3.5 to 9.0 with a detection limit of 4.37×10^?8 M. The sensor displays very good discrimination toward Cd(II) ions with regard to most common cations. The proposed sensor shows a short response time for whole concentration range (ca. 8 s). The effects of the cationic (tetrabutylammonium chloride, TBC), anionic (sodium dodecyl sulfate, SDS) and nonionic (Triton X‐100) surfactants were investigated on the potentiometric properties of proposed cadmium‐selective sensor. The proposed sensor based on KTt^2,6‐xylyl ionophore has also been used for the direct determination of cadmium ions in different water samples and human urine samples.     

Amide and Acyl‐Hydrazine Functionalized Calix[4]arenes as Carriers for Hydrogen Phosphate Selective Electrodes

Anion‐selective solvent polymeric membrane based on hydrogen bond‐forming, neutral ionophores with amide or acyl‐hydrazine groups are described. The use of the two calix[4]arenes results in anion‐selective electrodes with a selectivity for phosphate. The electrodes of the optimum characteristic have the composition of 1 wt% ionophore, 66 wt% o‐NPOE, 33 wt% poly (vinyl chloride) (PVC) and TDMACl (15 or 30 mol% relative to the ionophore 1 and 2 , respectively). The optimized membrane electrodes show Nernstian responses towards monohydrogen phosphate (?29.1 and ?29.3 mV/decade) based on ionophore 1 and 2 , respectively, in a wide concentration range (1.0×10^?5 to 1.0×10^?2 or 1.0×10^?5 to 1.0×10^?1 M). The selectivity coefficients are determined with the fixed interference method and the activity ratio method. The electrodes display an anti‐Hofmeister series selectivity pattern and highly selective for HPO₄^2? over Cl^?, Br^?, CH₃COO^?, NO₃^? and SO₄^2?. The lifetime of the electrodes is at least 1 month and their response time is found to be 25 s. The proposed sensors could be put to analytical use both by direct potentiometry as well as potentiometric titration.     

A New Silver(I) Potentiometric Sensor Based on a Calix[4]arene Substituted at the Narrow Rim by Amide/Phosphoryl Groups

A coated‐wire type silver ion‐selective electrode has been constructed using a modified p‐tert‐butyl‐calix[4]arene by amide‐phosphoryl groups, named 5, 11, 17, 23‐tetra‐tert‐butyl‐25, 27‐bis(diethylcarbamoylmethoxy)‐26,28‐bis(diphenylphosphinoylmethoxy)calix[4]arene (Calix), as neutral carrier. A plasticized PVC membrane containing 30% PVC, 60% ortho‐nitrophenyloctylether (NPOE), 2% sodium tetraphenylborate (NaTPB) and 8% “Calix” was coated on a graphite rod. The prepared electrode exhibited a linear Nernstian response over the range 1 × 10^?6 to 1 × 10^?2 M with a slope 58.4 (±0.2) mV per decade change and a detection limit of 6.3 × 10^?7 M. The working pH range of the sensor is 4‐6.7. It is found that the dynamic response time of the electrode to achieve a steady potential was very fast (～11 s). The selectivity of the sensor relative to NH₄⁺, Li⁺, Na⁺, K⁺, Ca²⁺, Sr²⁺, Ba²⁺, Mn²⁺, Pb²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Fe³⁺, La³⁺, Sm³⁺ and Th⁴⁺ was examined. The prepared electrode exhibits adequate stability with good reproducibility (57.6 ± 0.5 mV per decade change for 10 weeks). It was successfully used as an indicator electrode in potentiometric titration of silver ions with standard solution of EDTA. The sensor was also used for silver ion measurements in various synthetic samples.     

Highly Selective Salicylate Membrane Electrode Based on N,N＇- （Aminoethyl）ethylenediamide Bis（2-salicylideneimine） Binuclear Copper（Ⅱ） Complex as Neutral Carrier

A new ion selective electrode for salicylate based on N,N＇-（aminoethyl）ethylenediamide bis（2-salicylideneimine） binuclear copper（Ⅱ） complex [Cu（Ⅱ）2-AEBS] as an ionophore was developed. The electrode has a linear range from 1.0 × 10^-1 to 5.0 ×10^-7 mol·L^- 1 with a near-Nemstian slope of （ - 55 ±1 ） mV/decade and a detection limit of 2.0 × 10-7 mol·L^-1 in phosphorate buffer solution of pH 5.0 at 25 ℃. It shows good selectivity for Sal^- and displays anti-Hofmeister selectivity sequence： Sal^-〉SCN^-〉 ClO4^- 〉I^-〉 NO2^- 〉Br^-〉 NO3^- 〉Cl^-〉 SO3^2- 〉 SO4^2- The proposed sensor based on binuclear copper（Ⅱ）complex has a fast response time of 5-10 s and can be used for at least 2 months without any major deviation. The response mechanism is discussed in view of the alternating current （AC） impedance technique and the UV-vis spectroscopy technique. The effect of the electrode membrane compositions and the experimental conditions were studied. The electrode has been successfully used for the determination of salicylate ion in drug pharmaceutical preparations.     

Construction of a Highly Selective and Sensitive La(III) Sensor Based on N‐(2‐Pyridyl)‐N′‐(4‐methoxyphenyl)‐thiourea for Nano Level Monitoring of La(III) Ions

N‐(2‐Pyridyl)‐N′‐(4‐methoxyphenyl)‐thiourea (PMPT) was found to be a suitable neutral ion carrier for the construction of a highly selective and sensitive La(III) membrane sensor. Poly(vinyl chloride) (PVC) based membranes of PMPT with potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) as an anionic excluder and oleic acid (OA), dibutyl phthalate (DBP), benzyl acetate (BA) and o‐nitrophenyloctyl ether (NPOE) as plasticizing solvent mediators were constructed and investigated as La(III) membrane sensors. A membrane composed of PMPT‐PVC‐KTpClPB‐BA with the ratio 8.0 : 35.0 : 3.0 : 54.0 works well over a very wide concentration range (4.0×10^?8 to 1.0×10^?1 M) with a Nernstian slope of 19.6±0.2 mV per decade of activity between pH values of 4.0 and 9.0. The detection limit of the sensor was calculated to be 2.0×10^?8 M (ca. 3.0 ppb). The sensor displays very good discrimination toward La(III) ions with regard to most common metal ions and lanthanide ions. The proposed sensor shows a short response time for whole concentration range (ca. 12 s). For evaluation of the analytical applicability of the La(III) sensor, it was successfully used as an indicator electrode for the titration of La(III) ions with EDTA. It was also applied to the determination of fluoride content of two mouth wash preparation samples and monitoring of La(III) ions in some binary and ternary mixtures.     

Novel Ytterbium(III) Selective Membrane Sensor Based on N‐(2‐Pyridyl)‐N′‐(2‐Methoxyphenyl)‐Thiourea as an Excellent Carrier and Its Application to Determination of Fluoride in Mouth Wash Preparation Samples

The construction, performance, and applications of a novel ytterbium(III) sensor based on N‐(2‐pyridyl)‐N′‐(2‐methoxyphenyl)‐thiourea (PMT), as an excellent carrier, in plasticized poly(vinyl chloride) PVC matrix, is described. The influences of membrane composition and pH on the potentiometric response of the sensor were investigated. The sensor exhibits a nice Nernstian response for Yb(III) ion over a wide concentration range of 4 decades of concentration (1.0×10^?6–1.0×10^?2 M), and a detection limit of 5.0×10^?7 M. The response time of the electrodes is between 8 and 10 s, depending on the concentration of ytterbium(III) ions. The proposed sensor can be used for about 8 weeks without any considerable divergence in potential. The sensor revealed very good selectivity for Yb(III) in the presence of several metal ions. The best performance was observed for the membrane containing; 30% PVC, 59% o‐nitrophenyloctyl ether (NPOE) as solvent mediator, 7% PMT, and 4% sodium tetraphenyl borate (NaTPB). It was successfully applied as indicator electrodes in the potentiometric titration of Yb(III) with EDTA and for the determination of fluoride ion in two mouth wash formulations. The proposed La(III) sensor was found to work well under laboratory conditions. It was also used as an indicator electrode in titration of a 1.0×10^?4 M of Yb(III) with a standard EDTA solution (1.0×10^?2 M). It was also used for determination of Yb(III) ion in Xenotime .     

Electroanalytical performance of Cd(II) selective sensor based on PVC membranes of 5,5′‐(5,5′‐(benzo[c][1,2,5]thiadiazole‐4,7‐diyl)bis(thiophene‐5,2‐diyl))bis(N1,N1,N3,N3‐tetraphenylbenzene‐1,3‐diamine)

The construction and performance characteristics of polymeric membrane electrodes based on neutral ionophore 5,5′‐(5,5′‐(benzo[c][1,2,5]thiadiazole‐4,7‐diyl)bis(thiophene‐5,2‐diyl))bis‐(N1,N1,N3,N3‐tetraphenylbenzene‐1,3‐diamine) (L) for quantification of cadmium ions, are described. Effect of plastisizers dibutylpthalate (DBP), tri‐n‐butylphosphate (TBP), dioctylpthalate (DOP), o‐nitrophenyloctyl ether (o‐NPOE), 1‐chloronaphthalene (CN) and ionic additives sodium tetraphenylborate (NaTPB), potassium tetrakis p‐(chlorophenyl)borate (KTpClPB) was studied. Best performance was obtained with the membrane having a composition L?:?PVC?:?DBP?:?NaTPB?≡?2?:?37?:?59?:?2 (w/w; mg). The membrane electrode exhibits Nernstian response in the concentration range 6.3?×?10^?8 to 1.0?×?10?^?1?mol?L^?1 with detection limit 3.6?×?10^?8?mol?L^?1 and is not affected by H⁺ ions over a wide pH range 3.0–10.0. The electrode possess a fast response time of 10?s and shelf life period of 3 months. The analytical utility of the proposed electrode has demonstrated by its application in the determination of cadmium in water, medicinal plants and soil samples. It could also be used successfully as an indicator electrode in the potentiometric titration of Cd²⁺ with EDTA (ethylenediaminetetraacetic acid).     

牛磺酸双核铜络合物为载体的高选择性硫氰酸根离子电极的研究

本文报道了一种以牛磺酸双核铜络合物为中性载体的硫氰酸根PVC膜电极。该电极对硫氰酸根有良好的电位响应并呈现出anti-Hofmeister行为,其选择性顺序SCN^->I^->ClO₄^->Sal^->NO₃^-> NO₂^-> Br^- > Cl^- > SO₃^-> SO₄ ^2-。在20℃ pH 5.0的磷酸缓冲溶液中,其线性范围为1.0´10 ^-1~ 1.0´10^-6mol×L-1,检测线为8.0×10 ^-7mol•L^-1,斜率为 -56.5 mV/pcSCN^-。紫外、红外和交流阻抗研究表明电极的高选择性与载体的立体结构和分析物与中心金属离子的作用相关。将该电极用于废水和人体尿液中硫氰酸根的测定,获得了较满意的结果。     

Development of Polymeric Resin Ion‐exchanger Based Chloride Ion‐selective Electrode for Monitoring Chloride Ion in Environmental Water

A chloride ion‐selective electrode (ISE) membrane was developed by using a copolymeric ion‐exchanger resin (trimethyl ethenyl quaternary ammonium chloride polystyrene‐divinylbenzene copolymer resin, TMEQAC PSDVB), the ionophore ({μ‐[4,5‐Dimethyl‐3,6‐bis(dodecyloxy)‐1,2‐phenylene]}bis(mercury chloride), ETH9033), the plasticizer (bis(2‐ethylhexyl) sebacate, DOS), and the membrane substrate (polyvinylchloride, PVC). At 25 °C, the electrode exhibited an ideal Nernstian response of 59.2 mV/decade with the linear calibration concentration range from 1.0 × 10^?4‐1.0 × 10^?2 M (r² = 0.9930). The limit of detection was 2.45 ppm (6.9 × 10^?2 mM) and the measurement response time was less than 10 seconds. The working temperature range of electrode was 10‐45 °C. The working pH range for chloride ion measurement was 2.0‐11.0. Among the various anions examined in this work, only I^?, SCN^?, and MnO₄^? ions show significant interference to the electrode measurement. The chloride ISE can be used at least 72 days. The determination of chloride ion content in three kinds of environmental water sample with the electrode method was accurate (92‐95%) and precise (RSD < 4.4%) and did not show significance difference from the high‐performance liquid chromatography method.