8-hydroxyquinoline based neutral tripodal ionophore as a copper (II) selective electrode and the effect of remote substitutents on electrode properties

New PVC membrane ion selective electrodes based on 1,3,5-Tris(8-quinolinoxymethyl)-2,4,6-trimethylbenzene (MO8HQ) are reported. The basic sensing material belongs to the group of tripodal ionophores. Also their derivatives prepared by placing suitable substitutents at fifth position of 8-oxine moiety, i.e, 1,3,5-Tris(5-chloro-8-quinolinoxymethyl)-2,4,6-trimethylbenzene (5CHQ), 1,3,5-Tris(5-benzoyl-8-quinolinoxymethyl)-2,4,6-trimethylbenzene (5BHQ) and 1,3,5-Tris[(5-phenylhydroxymethylene)-8-quinolinoxymethyl]-2,4,6-trimethylbenzene (HYD-8HQ) ionophores have also been used to make copper-selective membrane electrodes. Among all the four electrodes, MO8HQ and HYD-8HQ ionophores based electrodes show excellent response towards Cu (II) ions. The electrodes having composition 33% PVC, 4% MO8HQ and 63% dibutyl phthalate (DBP) and 33% PVC, 6% HYD-8HQ, 63% dibutyl phthalate (DBP) exhibit a good Nernstian response to Cu (II) ions in the range of 1.0 × 10⁻⁶ to 1 × 10⁻¹ M. The electrode shows a reasonably fast response time of 15 s. The effect of pH and electrode response is also reported. It shows good selectivity for Cu (II) ions in comparison to heavy metal ions, transition metal ions and for alkali and alkaline earth metal ions. The electrode response and selectivity remains unchanged for at least 5 months. The electrode can be used as an indicator electrode in the potentiometric titration of Cu (II) ions with EDTA.     

含嘧啶环的双冠醚——V.双冠醚为载体的碱金属离子选择性电极的研究

本文报道由5-硝基-6-三氟甲基嘧啶环桥联苯并-12-冠-4、苯并-15-冠-5和苯并-18-冠-6的三种新的双冠醚的合成。用它们作为载体分别制成钠、钾和铯离子选择性电极，测定了电极的响应功能、选择性系数和适用的pH范围。结果表明三种电极都有较好的性能。     

基于Schiff-base结构化合物载体的汞离子选择性电极的制备与表征

高产率合成了一种新的Schiff-base结构化合物,并将其表征为高选择性聚合物膜汞离子选择性电极载体.考察了不同增塑剂及离子交换剂对膜电极响应性能的影响,在最佳膜组分条件下测得该电极对汞离子的线性响应范围为1.0×10-6 ～3.0×10-4 mol/L,响应斜率为(29.3±0.3) mV/dec,检出限为2.6×...     

含嘧啶环的双冠醚——Ⅲ.用双冠醚作载体的PVC膜离子选择性电极性质的研究

合成了九种用嘧啶环桥联的新的双冠醚,其中分别含有苯并-12-冠-4、(1、47)、苯并-15-冠-5(2、5、8)和苯并-18-冠-6(3、6、9 )。用它们作为载体分别制成钠、钾和铯离子选择性电极,测定了电极的选择性系数。结果表明,电极(7)(8)(9)具有较好的性能。     

中性载体可咯化合物应用于银离子电位传感器的研究

研制了一种以5,10,15-三(五氟苯基)可咯[H_3(tpfc)]为活性组分物质、以邻硝基苯辛醚o-NPOE为增塑剂、以四苯硼钠为亲脂性大阴离子添加剂的PVC膜电极(4种物质的质量比为3:3:62:32),电极能斯特斜率为54.8 mV/decade、工作浓度范围为5.1×10~(-6)～0.1 mol/L,pH为4.0～8.0,响应时间不超过30 s,该电极对银离子能抵抗来自Hg~(2+)、Pb~(2+)等离子干扰,表现出较高的选择性.这种传感器可用于对实际矿石样品进行检测.     

Nickel(II) selective membrane potentiometric sensor using a recently synthesized mercapto compound as neutral carrier

A PVC membrane electrode for Ni²⁺ ions based on a recently synthesized mercapto compound, as an ionophore was prepared. The electrode exhibits a Nernstian slope of 28-30 mV per concentration decade at wide concentration range of (1.0×10⁻²-1.0×10⁻⁷ M). It has a fast response time of <15 s and can be used for at least 4 weeks. The potentiometric response is independent of the pH of the test solution in the pH range 5-8.5. The proposed electrode revealed good selectivities over a wide variety of other cations including alkali, alkaline earth, transition and heavy metal ions. It was successfully applied to the direct determination and potentiometric titration of nickel ion with EDTA.     

A novel potassium ion membrane sensor based on rifamycin neutral ionophore

A novel potentiometric membrane sensor for potassium ion based on the use of rifamycin as a neutral ionophore is described. The sensing membrane is formulated with 2 wt.% rifamycin-SV, 69 wt.% dibutylsebacate plasticizer and 29 wt.% PVC. Linear and stable potential response with near-Nernstian slope of 56.7 +/- 0.2 mV decade(-1) are obtained over the concentration range 1 x 10(-1)-3 x 10(-5) M K(+). The detection limit is 0.3 microg ml(-1) K(+), the response time is 10-30 s and the working pH range is 4-11. Responses of the sensor toward alkali and alkaline earth metal ions are in the order K(+) > Rb(+) > Cs(+) > Na(+) > NH(4)(+) > Ba(2+) > Mg(2+) > Ca(2+) > Sr(2+) > Li(+). The selectivity coefficient data reveal negligible interference from transition metal ions. Direct potentiometric determination of K(+) in the presence of 10-50-fold excess of alkali and alkaline earth metals gives results with an average recovery of 99.1%, and a mean standard deviation of 1.2%. The data agree fairly well with those obtained by flame photometry.     

Mercury ion selective poly(aniline) solid contact electrode based on 2-mercaptobenzimidazol ionophore

A mercury(II) ion selective poly(aniline) solid contact electrode based on 2-mercaptobenzimidazol (2MBI) ionophore as a sulfur containing sensing material was successfully developed. The electrode exhibits a good linear response of 29.1 mV/decade (at 20 ± 0.2°C, r ² = 0.997) within the concentration range of 1 × 10^?2?1 × 10^?7 M Hg(II). The composition of this electrode was: ionophore 0.100, polyvinylchloride (PVC) 0.330, dibutylphthalate (DBP) 0.470, potassiumtetrakis(4-chlorophenyl)borate (KTpCIPB) 0.090, and oleic acid (OA) 0.010. A poly(aniline) solid contact electrode based on 2MBI with DBP and OA plasticizers exhibited the best response characteristics of the results obtained for similarly coated wire type electrodes and solid contact electrodes based on only one DBP plasticizer. The electrode shows good selectivity for mercury(II) ions in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.3?C8.0 and the standard deviation in the measured EMF difference was ±0.5 mV in a mercury nitrate sample solution of 1.0 × 10^?2 M and ±1.1 mV in a mercury nitrate sample solution of 1.0 × 10^?3 M. The stabilization time was less than 15 min and the response time was less than 33 s. The electrode was applied as a sensor for the determination of Hg(II) content in a sea water sample and some amalgam alloys. The results show good correlation with data obtained by atomic absorption spectrometry.     

含嘧啶环的双冠醚 V.双冠醚为载体的碱金属离子选择性电极的研究

本文报道由５－硝基－６－三氟甲基嘧啶环桥联苯并－１２－冠－４、苯并－１５－冠－５和苯并－１８－冠－６的三种新的双冠醚的合成。用它们作为载体分别制成钠、钾和铯离子选择性电极，测定了电极的响应功能、选择性系数和适用的ｐＨ范围。结果表明三种电极都有较好的性能。     

A calixarene based fluorescent Sr2+ and Ca2+ probe

A fluorescent probe, PyCalix, which has two pyrene moieties at the lower rim of a calix[4]arene fixed in the cone conformation was synthesized and its complexation behavior with alkali and alkaline earth cations was studied by fluorescence spectrometry. The compound showed intramolecular excimer emission at approximately 480 nm in the fluorescence spectra. Upon complexation with alkaline earth metal cations, a decrease of excimer emission was observed. The decrease of excimer emission was accompanied by an increase of monomer emission of pyrenes at 397 nm. The order of complexation constants of PyCalix with metal ions was Sr(+ approximately Ca2+ > Ba2+ > Mg2+ > K+ > Na+ > Cs+ for all reagents. PyCalix doped polyvinyl chloride (PVC) membrane was fabricated and our results showed that this membrane can be used for selective detection of Sr2+.     

双酰胺双(3'-正十五烷基-苯并-15-冠-5)PVC膜钾离子选择电极的研究

本文合成了十个双酰胺型双(3'-正十五烷基-苯并-15-冠-5)化合物, 制成的PVC膜钾离子选择电极, 性能优良.     

Synthesis of a new oxime and its application to the construction of a highly selective and sensitive Co(II) PVC-based membrane sensor.

A cobalt(II) ion-selective membrane sensor has been fabricated from a poly vinyl chloride (PVC) matrix membrane containing a new oxime compound (oxime of 1-(2-oxocyclohexyl)-1,2-cyclohexanediol, OXCCD) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as an anionic excluder and o-nitrophenyloctylether (o-NPOE) as a plasticizing solvent mediator. The membrane sensor exhibits a linear potential response in the concentration range of 1.0 x 10(-1) - 1.0 x 10(-6) M of Co2+. The electrode displays a Nernstian slope of 29.8 mV decade(-1) in the pH range of 3.5 - 8.0. The sensor also exhibits a fast response time of < 25 s. The detection limit of the proposed sensor is 9.0 x 10(-7) M (approximately 40 ng/ml), and it can be used over a period of two months. The selectivity of the sensor with respect to other cations (alkali, alkaline earth, transition and heavy metal ions) is excellent. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Co2+ with EDTA and for the direct determination of Co(II) in wastewater of the electroplating industry.     

Novel potentiometric sensor for monitoring beryllium based on naphto-9-crown-3.

A novel poly(vinyl chloride) (PVC) membrane electrode based on naphto-9-crown-3 was prepared and tested for the selective detection of beryllium ions. A suitable lipophilicity of the carrier and appropriate coordination ability were found to be essential for designing an electrode with good response characteristics. A PVC membrane with 9% naphtho-9-crown-3 carrier, 58% o-NPOE plasticizer, 3% tetraphenylborate anionic excluder and 30% poly(vinyl chloride) satisfied these requirements. The proposed sensor displayed a linear response to beryllium over a wide concentration range of 1.0 x 10(-1)-8.0 x 10(-6) M with a Nernstian slope of 29.5 mV per decade. The electrode showed very short response time (<15 s) and could be used in the pH range 3.5-9.0. The selectivity coefficient for alkali, alkaline earth, transition and heavy metal ions was smaller than 4.0 x 10(-4). The sensor was successfully used as an indicator electrode in the potentiometric titration of Be2+ with EDTA. The proposed Be(II) sensor was also used for the determination of Be2+ ions in binary mixtures.     

Samarium(III)-PVC-Membrane Sensor Based on Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline

Abstract

2-Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EED) was found to be a suitable neutral ionophore for the preparation of a highly selective samarium (Sm)(III) membrane sensor. Poly vinylchloride (PVC)–based membranes of EED with sodium tetraphenyl borate (NaTPB) as an anionic additive and dibutylphthalate (DBP), nitrobenzene (NB), and acetophenone (AP) as plasticizing solvent mediators were prepared and investigated as Sm(III) sensors. The sensor exhibited a Nernstian response over a concentration range of 1.0 × 10^?6 to 1.0 × 10^?2 M, with a detection limit of 5.0 × 10^?7 M. The best performance was achieved with a membrane composition of 30% PVC, 66% dibutyl phthalate (DBP), 2% EED, and 2% sodium tetraphenyl borate (NaTPB). It has a very short response time, in the whole concentration range (～10s), and can be used for at least 10 weeks. The proposed electrode shows a very good selectivity toward Sm(III) ions over a wide variety of cations, including alkali, alkaline earth, transition-metal, and heavy-metal ions. The sensor was applied to the determination of Sm ions in binary mixtures.     

Ultrafine Na-4-mica: uptake of alkali and alkaline earth metal cations by ion exchange

The cation exchange properties of alkali and alkaline earth metal cations at room temperature were investigated on an ultrafine, highly charged Na-4-mica (with the ideal mica composition Na4Mg6Al4Si4O20F4.xH2O). Ultrafine mica crystallites of 200 nm in size led to faster Sr2+ uptake kinetics in comparison to larger mica crystallites. The alkali metal ion (K+, Cs+, and Li+) exchange uptake was rapid, and complete exchange occurred within 30 min. For the alkaline earth metal ions Ba2+, Ca2+, and Mg2+, however, the exchange uptake required lengthy periods from 3 days to 4 weeks to be completed, similar to its Sr uptake, as previously reported. Kinetic models of the modified Freundlich and parabolic diffusion were examined for the experimental data on the Ba2+, Ca2+, and Mg2+ uptakes. The modified Freundlich model described well the Ba2+ ion uptake kinetics as well as that for the Sr2+ ion, while for the Ca2+ and Mg2+ ions the parabolic diffusion model showed better fitting. The alkali and alkaline earth ion exchange isotherms were also determined in comparison to the Sr2+ exchange isotherm. The thermodynamic equilibria for these cations were compared by using Kielland plots evaluated from the isotherms.     

New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd(2+) was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship between structures of ionophores and membrane characteristics were explored. The ionophore IV which composed of two opposites TPA units on the calix[4]arene compartment showed the best selectivity toward Cd(2+). The best membrane electrode was fabricated from ionophore IV (10.2 mmol kg(-1)) with KTpClPB (50.1 mol% related to the ionophore) as an ion exchanger incorporated in the DOS plasticized PVC membrane (1:2; PVC:DOS). The Cd-ISE fabricated from ionophore IV exhibited good properties with a Nernstian response of 29.4±0.6 mV decade(-1) of activity for Cd(2+) ions and a working concentration range of 1.6×10(-6)-1.0×10(-2)M. The sensor has a fast response time of 10s and can be used for at least 1 week without any divergence in potential. The electrode can be used in the pH range of 6.0-9.0. The proposed electrodes using ionophores III and IV were employed as a probe for determining Cd(2+) from the oxidation of CdS QDs solution and the real treatment waste water sample with excellent results.     

Fluorescent iminodiacetamide derivatives as potential ionophores for optical zinc ion-selective sensors.

Fluorescent sensor molecules were synthesized by conjugation of iminodiacetamide derivatives with fluorescent moieties of different structures and their UV-visible and fluorescent properties were characterized in acetonitrile solvent. The fluorescent measurements revealed that the N-(2-naphthyl) and N-phenyl derivatives exhibit a distinct zinc ion-selectivity over alkali and alkaline earth metal ions, while N-(anthrylmethyl) and N-(3-methoxyphenyl) derivatives do not possess any ion-selectivities. In contrast to the fluorescent measurements, all ligands show Zn(2+) selectivity over Ca(2+) and Mg(2+) ions in plasticized PVC membranes using potentiometric signal transduction. This observation found for N-(anthrylmethyl) and N-(3-methoxyphenyl) derivatives can be ascribed to the more hindered interaction between the signalling group of the ionophore and the central metal ion in PVC membranes than in acetonitrile solution upon complexation. From the fluorescent measurements it can also be concluded that the ligands with metal ions form complexes mainly with 2:1 stoichiometry (L(2)M). On complex formation a considerable decrease in the fluorescent intensity was observed for all ligands except the N-(anthrylmethyl) derivative, where a 25 - 30 fold fluorescence enhancement was found, which is explained by the photoinduced electron transfer (PET) mechanism. All ionophores exhibited serious hydrogen ion interference, therefore complexation-induced spectral changes were measured in aprotic acetonitrile solution.     

含嘧啶环的双冠醚(Ⅳ)

前文已报道由啶环桥联两个苯并冠醚的双冠醚的合成与性质。由于嘧啶环的刚性较大,能把两个冠醚单元固定在有效地协同作用位置,因此以它们作中性载体的离子选择性电极具有较好的选择性。为了进一步研究这类双冠醚的性质,我们合成了四种嘧啶环桥联两个脂肪族冠醚的双冠醚,并经元素分析、IR、′HNMR鉴定。     

Reversible electrochemical oxidation of (CH)x films

Thallium(I)-selective PVC membrane electrodes based on bis(crown ether)s containing benzo-15-crown-5 moiety were prepared, using o-nitrophenyloctylether(NPOE) or dipentylphthalate(DPP) as the plasticizer of the PVC membrane. Selectivity coefficients for various alkali and alkaline earth metal ions, k_TIM, were sufficiently small, and were compared with those of the corresponding monocyclic analog and valinomycin. These electrodes show excellent electrode properties, and the electrode response was stable in a wide pH range.     

Solid contact Zn2+ -selective electrode with low detection limit and stable and reversible potential

A new solid contact Zn²⁺ polyvinylchloride membrane sensor with 2-(2-Hydroxy-1-naphthylazo)-1,3,4 -thiadiazole as an ionophore has been prepared. For the electrode construction, ionic liquids, alkylmethylimidazolium chlorides are used as transducer media and as a lipophilic ionic membrane component. The addition of ionic liquid to the membrane phase was found to reduce membrane resistance and determine the potential of an internal reference Ag/AgCl electrode. The electrode with the membrane composition: ionophore: PVC: o-NPOE: ionic liquid in the percentage ratio of (wt.) 1:30:66:3, respectively, exhibited the best performance, having a slope of 29.8 mV decade^?1 in the concentration range 3×10^?7–1×10^?1 M. The detection limit is 6.9×10^?8 M. It has a fast response time of 5–7 s and exhibits stable and reproducible potential. It has a fast response time of 5–7 s and exhibits stable and reproducible potential, which does not depend on pH in the range 3.8–8.0. The proposed sensor shows a good and satisfactory selectivity towards Zn²⁺ ion in comparison with other cations including alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for direct determination of zinc ions in tap water and as an indicator electrode in potentiometric titration of Zn²⁺ ions with EDTA.