2-Amino-4-(4-aminophenyl)thiazole application as an ionophore in the construction of a Lu(III) selective membrane sensor

A derivative of thiazole（AAT） has been explored as a sensing material for preparation a selective Lu（III） PVC-based membrane sensor.The proposed sensor exhibits a Nernstian response over a wide concentration range from 1.0×10^-6 to 1.0×10^-1 mol/L of Lu（Ⅲ） and the detection limit is 5.7×10^-7 mol/L.The sensor response is independent of pH of the solution in the range 3.2-8.8 and possesses the advantages of fast response time（～6） and in particular,good selectivity to the lutetium ions with regard to most common metal ions,and especially all lanthanide ions.     

Fabrication of a Ho~(3+)-PVC membrane sensor based on N-phenyl-2-(thiophen-2-ylmethylene)hydrazinecarbothioamide for determination of holmium ions

In this research,a new poly（vinyl chloride）（PVC） membrane sensor for Ho³⁺ ion based on N-phenyl-2-（thiophen-2- ylmethylene）hydrazinecarbothioamide（PHC） as an ionophore was prepared.This sensor demonstrated good selectivity and sensitivity towards the holmium ion in comparison with variety of cations,including alkali,alkaline earth,transition and heavy metal ions.The effect of membrane composition and pH on the response properties of the electrode was investigated.In detail,the suggested sensor exhibited a Nernstian behavior(with a slope of 20.4±0.3 mV decade^-1) in the range of 1.0×10^-6 to 1.0×10^-2 mol/L with a detection limit of 6.2×10^-7 mol/L.The response time was relatively quick in the whole concentration range（～5 s）.The sensor usage was found to be at least 10 weeks in a pH range of 3.3-10.9.It was successfully applied in determination of fluoride ions in mouth wash preparations.     

N~1,N~2-Bis[1-(2-hydroxyphenyl)methylidene]ethanedihydrazide as a neutral ionophore for preparation of a new Ho~(3+) PVC-membrane sensor

N¹,N²-Bis[1-（2-hydroxyphenyl）methylidene]ethanedihydrazide（MEH） was used as new compound which plays the role of an excellent ion carrier in the fabrication of a Ho（Ⅲ） membrane electrode.The electrode shows a good selectivity for Ho（Ⅲ） ion with respect to most common cations including alkali,alkaline earth,transition and heavy metal ions.This electrode has a wide linear dynamic range from 1.0×10^-6 to 1.0×10^-2 mol/L with a Nernstian slope of 19.8±0.3 mV per decade and a low detection limit of 5.8×10^-7 mol/L in the pH range of 2.5-9.8,while the response time was rapid（<10 s）.The suggested sensor was applied to the determination of Ho（Ⅲ） ions in tap water and river water samples.     

Application of 2,2'-dithiobis(4-methylthiazole) as sensing material for construction of Lu~(3+) PVC-membrane sensor

In this work a new Lu³⁺ PVC-membrane sensor based on 2,2’-dithiobis（4-methylthiazole）（TMT） has been fabricated.The sensor exhibits a Nernstian slope of 19.6±0.4 mV decade（?） in the concentration range of 1.0×10⁶-1.0×10² mol L¹ and a detection limit of 6.8×10⁷ mol L¹.It could work well in the pH range of 2.7-9.6.The selectivity of the sensor against a lot of common alkaline,alkaline earth,transition,heavy metals and specially lanthanide ions was very good.     

Iodide-selective polymeric membrane electrode based on copper(Ⅱ) bis(N-2-bromophenylsalicyldenaminato) complex

A PVC membrane electrode based on copper（Ⅱ） bis（N-2-bromophenylsalicyldenaminato） as ionophor was prepared.The ion selective electrode was tested by inorganic anions and showed a good selectivity for iodide ion.This sensor exhibited Nernstian behavior with a slope of—57.8 mV per decade at 25℃.The proposed electrode showed a linear range from 1.0×10⁵ to 1.0×10^-1 mol/L with a detection limit of 5.0×10^-6 mol/L.The electrode response was independent of pH in the range of 3.0- 10.0.The proposed sensor was applied to determine the iodide in water and antiseptic samples.     

Potentiometric determination of mefenamic acid in pharmaceutical formulation by membrane sensor based on ion-pair with basic dye

The characteristics,performance and application of membrane sensors based on ion-pair Brilliant Green mefenamate are described.The sensor’s response to the mefenamate ion has the sensitivity of （86.0±2.0） mV/pC over the range of 9×10^-5-1×10^-2moI/Land the detection limit of 4.5×10^-5mol/L at pH 8.5-12.The sensor is easily assembled at a relatively low cost and has fast response time（5-10 s）.The proposed sensor displayed good selectivity for mefenamate ion in the presence of different substances.It was used to determine mefenamic acid in pharmaceuticals.     

A bismuth(Ⅲ) PVC membrane ion selective electrode based on5-(3,4,5-trimethoxyphenyl)-4-amino-1,2,4-triazole-3-thiol

The construction,performance characteristics and application of a new bismuth(Ⅲ) PVC membrane electrode based on 5-(3,4,5-trimethoxyphenyl)-4-amino-1,2,4-triazole-3-thiol are reported in this paper.The designed sensor exhibited a Nernstian response for Bi~(3+) ion ranging from 5.0×10~(-7) mol/L to1.0×10~(-2) mol/L with a slope of 19.8 mV/decade.The operational pH range of the sensor is 3.0-6.0.The electrode shows a response time of 6 s and can be used for at least five weeks without any considerable divergence in potentials.It exhibits very good selectivity relative to a wide variety of alkali,alkaline earth,transition and heavy metal ions.The proposed electrode could be used as an indicator electrode in potentiometric titration of Bi~(3+) ions with EDTA and in the determination of Bi~(3+) content in stomach medicine.     

Construction of a PVC based 15-crown-5 electrochemical sensor for Ag(Ⅰ) cation

The macrocyclic ligand,15-crown-5,was used as an ionophore for fabrication of a polyvinyl chloride(PVC) based membrane sensor for Ag(Ⅰ) cation.For construction of the Ag(Ⅰ) cation selective electrode the best response characteristics were obtained using the composition: 15-crown-5/PVC/o-nitrophenyloctylether(NPOE)/sodium tetraphenyl borate(NaTPB) in the percentage ratio of 5.6/30/60.5/3.9(w/w/w/w).The electrochemical sensor shows a linear dynamic range 1.0 10 7–1.0 10 1mol/L and a Nernstian slope of 58.9 0.5 mV/decade with a detection limit of 8.09 10 8mol/L for Ag(Ⅰ) cation.It has a fast response time of 10 s and can be used for at least 8 weeks without any considerable divergences in its potential response.It was successfully used as an indicator electrode in potentiometric titration of Ag(Ⅰ)cation with I and Cl anions and also for the determination of this metal cation in radiology waste water.     

Thiocyanate ion selective electrode based on bis(N-3-methylphenyl salicylidenaminato)copper(Ⅱ) ionophore

In this work a PVC membrane electrode based on bis(N-3-methyl phenyl salicylidenaminato)copper(II)as ionophore was prepared.The electrode was tested by inorganic anions and showed good selectivity for thiocyanate ion.This sensor showed Nerstian behavior with a slope of a-59.3 mV per decade at 25℃.The proposed electrode exhibited a wide linear range from 1.0 × 10~(-6) mol/L to 1.0× 10~(-1) mol/L with a detection limit of 5.0×10~(-7) mol/L.The electrode response was independent of pH in the range of 4.0-10.0.The response time is about 9-21s,and the electrode can be used for over 60 days without considerable deterioration.The prepared sensor was applied as an indicator electrode in potentiometric titration of SCN with Ag~+ ion and to determine the thiocyanate in samples of urine and saliva.     

A novel cell-impermeable fluorescent zinc sensor containing poly(ethylene glycol) chain

A novel cell-impermeable zinc sensor was synthesized by incorporating poly（ethylene glycol）（PEG） to N-（8-quinolyl）-p-aminobenzenesulfonamide （HQAS） group.The polymeric zinc sensor combines both valuable features of HQAS and PEG.The HQAS of the sensor has the similar functions to TSQ,and exhibits a good fluorescence response to Zn²⁺ but poor fluorescence responses to other metal ions.The PEG chain can prevent the sensor to permeate healthy cell membrane.The stained experiments with the yeast cells as model showed that the sensor cannot stain the healthy yeast cells,but only the damaged or died yeast cells. These results indicated the novel zinc probe was a typical cell-impermeable zinc sensor.     

A highly selective solid-contact electrode for Ag~+ based on a monoazathiacrown ether ionophore

A new solid-contact Ag⁺-selective electrode was prepared with 9,10,12,13,24,25-hexahydro-5H,15H,23H-dibenzo [b,q][1,7,10,13,19,4,16]-entathiadiazacyclodocosine-6,16（7H,17H）-dione as ionophore,and cc,a>-dihexylsexithiophene（DH- 6T） ion-to-electron transducer.The sensor exhibited a working concentration range of 10⁸ to 10^-3 mol/L,with a near-Nernstian slope of 55.1±0.2 mV/dec and detection limit of 1.7×10^-9 mol/L.The fabricated electrodes demonstrated excellent selectivity over the most common monovalent and divalent cations.     

Temperature effect on the kinetics of persulfate oxidation of p-chloroaniline

The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline（PCA） in aqueous solutions was measured at five different temperature conditions and at four different oxidant concentrations.The PCA degradation was found to follow a pseudo-first-order decay model when the persulfate was excessive.The pseudo-first-order rate constants of PCA degradation by persulfate（50 mmol/ L） at pH 7.0 are 0.12×10^-4,0.28×10^-4,0.43×10^-4,0.83×10^-4,1.32×10^-4 s^-1 at 10,20,30,40 and 50℃,respectively. Under the above reaction conditions,the reaction has activation energy of 49.97 kJ/mol.The observed rate was found to be function of temperature and oxidant concentration.Raising temperature and increasing persulfate concentration can significantly accelerate the PCA degradation.     

Potentiometric determination of diclofenac in pharmaceutical formulation by membrane electrode based on ion associate with base dye

The characteristics,performance and application of membrane electrode based on ion associate of diclofenac with base dye Safranine T are described.The electrode response to diclofenac has the sensitivity of 47±1.0 mV decade~(-1)over the range of 5×10~(-5)to 5×10~(-2)mol/L at pH 6-12,and the detection limit of 3.2×10~(-5)mol/L.The electrode is easy assembled at a relatively low cost has fast response time(2-4 s)and can be used for a period up to 3.5 months without any considerable divergence in potential.The proposed sensor displayed good selectivity for diclofenac in the presence of different substances.It was used to determine diclofenac in pharmaceuticals by means of the standard addition method.     

A highly selective chemosensor for copper ion based on ICT fluorescence

Simple structural compounds 1 to 3 were synthesized.The presence of Cu²⁺ resulted in the fluorescence and absorption spectra change of 1 and 2,which indicated that 1 and 2 showed a highly selective response to Cu²⁺ over other metal ions.However,3 showed no selectivity for metal ions,which means that the compound could bind with several metal ions,such as,Ni²⁺,Zn²⁺,Cd²⁺.Hg²⁺, Pb²⁺,Fe³⁺,Mg²⁺,Ca²⁺,and Co²⁺,except Cu²⁺ and Ag⁺.The different spectral responses were attributed to the difference in binding sites for 1 and 3.     

Synthesis and magnetic properties of complexes of a conjugated hyperbranched polymer containing bithiazole rings

A novel conjugated hyperbranched polymer containing bithiazole rings（PBTADB） was synthesized by polycondensation of 1,3,5-benzenetricarboxaldehyde and 2,2’-diamino-4,4’-bithiazole（DABT）.The structure of the hyperbranched polymer was confirmed by FT-IR and ¹H-NMR.PBTADB dissolved in organic polar solvents such as DMSO and NMP.Bithiazole rings were introduced to provide bidentate N-donor sites for binding metal ions.The metal complexes were prepared by chelation of the polymer with Co²⁺ and Sm³⁺.The magnetic behavior of coordination compounds was measured as a function of magnetic field strength（0-4.8×10⁶ A/m） at 5 K and as a function of temperature（5-300 K） at magnetic field strength of 2.4×10⁶ A/m.The magnetic hysteresis loops of PBTADB-Sm³⁺and PBTADB-Co²⁺showed the typical ’S’ shape at 5 K with the Curie-Weiss temperature T_θ=96 K and 41 K respectively.The results show that they exhibit properties of soft ferromagnetic materials.     

A novel dithiourea and its response to metal ions

The synthesis,characterization,and its response to metal ions of a novel thiourea N,N’-diethoxycarbonyl-A",iV″’-（1,2- ethylidene） dithiourea was reported.The results show that this dithiourea with new structure can react with Cu²⁺ and Ni²⁺ separately,and has a best selectivity to Fe³⁺ ions.Bench-scale flotation tests were also carried out,verifying it has higher copper flotation recovery and better selectivity to sulfide ores containing Cu compared with universal collectors.     

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 from1.0×10~(-1) to 5.0×10~(-7) mol·L~(-1) with a near-Nernstian 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 displaysanti-Hofmeister selectivity seoquence:Sal~->SCN~->ClO_4~->I~->NO_2~->Br~->NO_3~->CI~->SO_3~(2-)>SO_4~(2-)The proposed sensor based on binuclear copper(Ⅱ)complex has a fast response time of 5-10 s and can be used forat least 2 months without any major deviation.The response mechanism is discussed in view of the alternating cur-rent(AC) impedance technique and the UV-vis spectroscopy technique.The effect of the electrode membranecompositions and the experimental conditions were studied.The electrode has been successfully used for the deter-mination of salicylate ion in drug pharmaceutical preparations.     

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.     

Cyclam Modified Carbon Paste Electrode as a Potentiometric Sensor For Determination of Cobalt(Ⅱ) Ions

A new modified carbon paste electrode based on cyclam as a modifier was prepared for the determination of Co(Ⅱ) ions. The proposed electrode shows a Nernstian slope 28.4 mV per decade over a wide concentration range 5.0×10-6_1.0×10-1 mol/L of Co2 ions with detection limit 2.5×10-6 mol/L. The sensor exhibits good selectivities for Co2 over a wide variety of other cations. It can be used as an indicator electrode in potentiometric titration of cobalt(Ⅱ) ions as well as in direct determination of cobalt(Ⅱ) ions in wastewater of acidic cobalt electroplating bath. The electrode shows Nernestian behavior in a solution of 25% ethanol.     

Electrosynthesis and characterization of poly(hydroxy-methylated-3,4-ethylenedioxythiophene) film in aqueous micellar solution and its biosensing application

A new and efficient synthetic route to hydroxymethylated-3,4-ethylenedioxylthiophene（EDOT-MeOH） was developed by a simple four-step sequence,and its global yield was approximately 41.06%.The poly（hydroxymethylated-3, 4-ethylenedioxylthiophene）（PEDOT-MeOH） film was electrosynthesized in aqueous sodium dodecylsulfate micellar solutions and characterized by different methods.The EDOT-MeOH possessed better water solubility,and lower onset oxidation potential than EDOT.The as-obtained PEDOT-MeOH film displayed good reversible redox activity,stability and capacitance properties in a monomer-free electrolyte,especially the good solubility of PEDOT-MeOH film in strong polar organic solvents such as dimethyl sulfoxide and tetrahydrofuran created a potential application in many different fields. Fluorescent spectra indicated that PEDOT-MeOH was a yellow-green-light-emitter with maximum emission at 568 nm.The as-formed PEDOT-MeOH film had good biocompatibility and was used for fabricating the electrochemical vitamin C biosensor.The proposed biosensor showed a linear range of 3×10^-6 mol/L to 1.2×10^-2 mol/L with the detection limit of 1μmol/L,a sensitivity of 95.6μA（mmol/L）^-1 cm^-2,and a current response time less than 10 s and a fairly good stability (The relative standard deviation was 0.43%for 20 successive assays,the proposed biosensor still retained 93.5%of bioactivity after 15 days storage.This result indicated that the prepared PEDOT-MeOH film as immobilization matrix of biologically-active species could be a promising candidate for the design and application of biosensor.