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.     

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.     

Electroanalysis and simultaneous determination of dopamine and epinephrine at poly(isonicotinic acid)-modified carbon paste electrode in the presence of ascorbic acid

A carbon paste electrode modified with electropolymerized fills of isonicotinic acid was developed.The modified electrode shows excellent electrocatalytic activity toward the oxidation of both dopamine(DA)and epinephrine(EP).Separation of the reduction peak potentials for dopamine and epinephrine was about 357 mV in pH 5.3 phosphate buffer solution(PBS)and the character was used for the detection DA and EP simultaneously.The peak currents increase linearly with DA and EP concentration over the range of 8.0×10-5 to 7.0×10-4 mol/L and 5.0×10-6 to 1.0×10-4 mol/L with detection limits of 2 × 10-5 and 1×10-6 mol/L,respectively.The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid(AA).     

Ag+存在下催化还原铬黑T及应用于Ag+检测

以铬黑T(EBT)为探针,在有Ag⁺存在的最优条件下,EBT被NaBH 4催化还原,体系在445 nm发射波长处荧光强度明显增强,基于此构建一种光学测定溶液中微量Ag⁺的方法。在最优条件下,Ag⁺浓度在(7.5×10-9~1.0×10^-6 mol·L^-1)范围内呈良好的线性关系,线性回归方程为ΔI F=5.59×10⁸ c-31(c,mol·L^-1,r=0.9966),Ag⁺的最低有效检测浓度为6.0×10^-8 mol·L^-1。在最优条件下,运用该方法对样品中Ag⁺浓度进行检测,样品中Ag⁺浓度的检测回收率在98.8%~102.4%之间,RSD=2.1%。该检测方法能够对水溶液中微量的Ag⁺进行有效定量检测,且操作简单、检测限低、灵敏度高。     

基于碳纳米管/Ag/MoS2转导层的全固态钙离子选择电极

构建了一种电势稳定性好的全固态钙离子选择电极(Ca²⁺-ISE),采用碳纳米管(CNT)/Ag/MoS₂为转导层,自制的三脚架化合物作为钙离子载体,制备固体接触式Ca²⁺-ISE。 系统分析了全固态Ca²⁺-ISE的稳定性、能斯特斜率、响应范围、选择性系数等主要性能,发现制备的固体接触式Ca²⁺-ISE在钙离子浓度为1×10^-6~1×10^-1 mol/L范围内呈现线性能斯特响应,响应斜率为28.1 mV/decade。 CNT/Ag/MoS₂的引入有利于提高固体接触式Ca²⁺-ISE的离子浓度线性响应范围,缩短电势平衡时间,降低测试能斯特斜率与理论值差,对于Ca²⁺-ISE的长期在线检测有重要研究意义。     

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.     

A bismuth(III) PVC membrane ion selective electrode based on 5-(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 Bi³⁺ ion ranging from 5.0×10^-7 mol/L to 1.0×10^-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 Bi³⁺ ions with EDTA and in the determination of Bi³⁺ content in stomach medicine.     

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.     

碘化钾-十六烷基三甲基溴化铵-水体系液固分离银的研究

本文利用碘化钾-十六烷基三甲基溴化铵-水微晶吸附体系研究了银离子的液固分离行为.分别考察了KI用量、CTMAB用量、溶液酸度、盐和放置时间对分离效率的影响,结果表明,当2％碘化钾溶液溶液和2.0×10-3 mol·L-1 CTMAB溶液的用量均为1.0 mL时,Ag+、I-、CTMAB+形成的三元缔合物AgI2-·CT...     

光敏氧化还原反应——四苯基卟啉类化合物光敏还原甲基紫精

在DMSO-H₂O混合溶剂中,用TPP和它的四种金属络合物作为敏化剂,EDTA作为电子给体,经可见光照射,成功地还原了甲基紫精。反应活性顺序为ZnTPP>TPP>MgTPP》CoTPP>CuTPP。对以ZnTPP为敏化剂的反应,我们测得其量子产率为φ_418nm=0.08。我们考察了ZnTPP、MV²⁺和EDTA的浓度以及氧气对反应的影响。在一定浓度范围内,我们发现,反应速度与MV²⁺和EDTA浓度之间的关系符合于从推测的反应机理导出的动力学方程。     

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.     

Erbium(Ⅲ) PVC membrane sensor based on N-(benzyloxycarbonyloxy)succinimide as a new neutral ionophore

In this study,a new Er³⁺ sensor based on N-（benzyloxycarbonyloxy）succinimide（BCS） as a neutral carrier has been constructed. The sensor exhibits potential linear response with a Nernstian slope of 20.5±0.4 mV/decade in the concentration range of 1.0×10^-6to 1.0×10^-2mol/L of Er³⁺.It has a very short response time（<10 s）,detection limit of 6.3×10^-7 mol/L and a good selectivity relative to a wide variety of other metal ions including common alkali,alkaline earth,heavy,and transition metal ions.It can be used in the pH range of 2.5-10.6 without any considerable divergence in potentials.The proposed sensor was successfully applied for the recovery of Er³⁺ ions spiked in tap and river water samples.     

Flow Injection Chemiluminescence Method for Nalbuphine Hydrochloride in Pharmaceutical Formulations Using Tris(2,2'-bipyridyl)ruthenium(II) Chloride-diperiodatocuprate(III) Reaction

Asensitive and selective method employing chemiluminescence(CL) coupled with flow injection(FI) is reported for nalbuphine hydrochloride(NAL) assay in pharmaceutical formulations. The enhancement effect of NAL on the CL reaction between tris(2,2'-bipyridyl)ruthenium(II) chloride-diperiodatocuprate(III) {Ru[(bpy)₃]²⁺-Cu(III) complex} in acidic medium is used as analytical measurement. The optimal conditions of the CL reaction were sulfuric acid 1.0×10^-3 mol/L, Ru[(bpy)₃]²⁺ 7.5×10^-5 mol/L, Cu(III)/Ag(III) complexes 4.0×10^-4/5.0×10^-4 mol/L, sample loop volume of 120 μL and flow rate of 2.5 mL/min. The sensitivities of the method in terms of detection(S/N=3) and quantification(S/N=10) limits are 5×10^-4 and 0.001 ppm(1 ppm=1 mg/L), respectively. The linear response of the instrument in the form of CL intensity with respect to NAL concentration is over the range 0.001-15.0 ppm(R²=0.9999) with relative standard deviation from 0.8% to 3.2% and injection throughput of 120 injection/h. The applications of the method include the quantitative analysis of NAL in pharmaceutical injection samples. Variations and the average results of the proposed method are not signi-ficantly different from the results of a reported method by applying F- and paired student t-test. The most likely CL reaction mechanism is written in accordance with spectrophotometric and CL studies.     

Cr3+比色荧光探针的合成及细胞成像应用

以2,3,3-三甲基-3H-苯并[e]吲哚和对二甲氨基苯甲醛为原料, 乙醇作溶剂, 在酸性催化条件下, 通过一步反应合成了比色荧光探针B. 在EtOH/HEPES(pH=7.4)体积比为9∶1的混合体系中, 向探针B溶液中加入Cr ³⁺后, 溶液颜色由淡黄色变为紫红色, 说明探针B可以对Cr ³⁺进行裸眼识别. 紫外-可见吸收光谱和荧光发射光谱分析表明, 探针B对Cr ³⁺的选择性好、 灵敏度高且对EDTA有良好的接力识别. 探针B对Cr ³⁺的结合常数K_a=0.28×10 ² mol/L, 检出限为1.90×10 ^-8 mol/L, 该检出限低于世界卫生组织(WHO)规定的饮用水中Cr ³⁺的最大含量(9.60×10 ^-8 mol/L). 利用荧光发射光谱对实际水样中Cr ³⁺的浓度进行了定量检测. 探针B也可应用于对活细胞中Cr ³⁺的检测, 具有较好的应用前景和实用价值.     

一种香豆素类锌离子荧光探针的合成及性能

通过Pechmann法使间苯二酚和乙酰乙酸乙酯发生脱水缩合反应,合成了4-甲基-7-羟基香豆素,再与六次甲基四胺反应,生成7-羟基-4-甲基-8-甲酰基香豆素,最终与吲哚酰肼发生席夫碱反应合成一种香豆素类荧光探针L。通过核磁共振波谱仪(NMR)、质谱(MS)、傅里叶变换红外光谱仪(FTIR)、荧光发射光谱仪和紫外可见分光光度计等技术手段研究该探针L的结构及其荧光性能。结果表明,探针L与Zn~(2+)的配合比为1∶1,对Zn~(2+)的检测限达到3.6×10~(-8)mol/L,降低了对Zn~(2+)的检测浓度,同时探针L对锌离子具有高选择性,可应用于在生物体内Zn~(2+)的检测。     

Interfacial properties of precipitate-based ion-selective electrodes : Rotating disk impedance measurements of the Ag2S/Ag (aqueous) interface

Three-electrode rotating disk impedance measurements were made from 31.6 kHz to 0.0178 Hz on Ag₂S/Ag⁺ (aqueous) and Ag₂S/Ag systems. Membranes were prepared from materials precipitated in excess of silver or sulfide ions, and stoichiometric mixtures. Impedances were analyzed, as a function of rotation rate and bathing activities, to isolate bulk conductivities, internal diffusion, surface kinetic and dissolution/crystallization impedances. High-frequency bulk resistivities, R_∞, varied by four with precipitation and pressing conditions. Resistivities were the same for solution and ohmic configurations for each preparation. For ohmic contacts, R_∞ and R(DC) were identical. Solution contact cells in 10^-1 M and 10^-2 M bathing silver ion solution gave identical frequency-dependent impedances which were independent of rotation rate. Thus, solution diffusional impedances and solution dependent surface kinetics were eliminated, and a finite Warburg, interior-Ag⁺-defect, diffusion impedance was indicated. Summation of bulk membrane and contact resistances, and this Warburg impedance served as a 'background' correction in analyzing dilute bathing solution interfacial impedances for surface effects. Corrected impedances in 10^-3 –10^-5 M AgNO₃ showed solution diffusional behaviour combined with surface kinetic and dissolution impedances. An iterative linear least-squares method resolved these quantities. The surface resistance suggests a potential-dependent rate constant; dissolution time constants were solution-independent and smaller than those for solution diffusion. Thus, dissolution can be a rate-limiting step in establishment of steady-state potentials.     

硫堇衍生化自组装膜修饰金电极的电化学性质及其对抗坏血酸的电催化氧化

将硫堇共价键合到自组装在金电极表面的半胱胺单分子层上,制成了衍生化自组装单分子膜修饰电极,并用电化学方法研究了它的电化学性质.循环伏安图显示其在pH＝7.7的磷酸盐缓冲液中,于－0.45～＋0.50V(vs.SCE)范围内有2对氧化还原峰.峰电位分别为E_pa¹＝214mV。E_pc¹＝82mV,E_pa2＝－75mV,E_pc2＝－160mV(vs.SCE).pH在5.0～9.0范围内,峰1有2个质子参与反应,峰2有1个质子参与反应.它的表面电子转移速率常数k_s＝0.02S^－1.此膜对抗坏血酸的氧化有催化作用,其氧化过电位较在裸金电极上降低了约250mV.催化电流与抗坏血酸的浓度在1.0×10^-6～4.0×10^-3mol/L范围内呈良好的线性关系.抗坏血酸催化氧化的异相速率常数为2.68×10^-3cm/s.     

金属有机骨架材料构建环丙沙星电化学传感器的研究

本文通过水热合成法合成了钴-对苯二甲酸金属有机骨架材料Co(BDC),并将其与聚丙烯酸钠(PAAS)混合后修饰到玻碳电极(GCE)表面,制得电化学传感器Co(BDC)-PAAS/GCE,通过循环伏安法和差分脉冲法研究了传感器的响应性能,并用于水产品中环丙沙星(CIP)检测.结果 表明,在碱性条件下,Co(BDC)-PA...     

一种简单快速检测汞离子的1,4-二硫苏糖醇膜修饰金平板电极

将1,4-二硫苏糖醇(DTT)自组装在100 nm厚的平整金膜表面, 形成DTT膜修饰金平板电极(GPE), 构建了一种新颖的简单、 快速测定汞离子的选择性电极分析方法. 通过电化学交流阻抗和循环伏安法探讨了该电极的响应原理, 即固定在Au表面的DTT通过另一端的巯基与汞离子发生强配位作用而吸附结合带正电荷的汞离子, 引起电极表面膜电位的变化, 从而选择性地识别汞离子. 实验结果表明, 该电极在pH=6.0的Tris-HCl缓冲溶液中对汞离子有良好的电位响应性能, 其线性范围为1.0×10^-8~1.0×10^-3 mol/L, 能斯特响应斜率为(29.62±0.2) mV/-pc(25 ℃), 检出限为5.1×10^-9 mol/L. 该汞离子检测电极的响应时间仅为20 s, 且有较好的重现性和稳定性. 通过测定各种离子的选择性系数, 发现Cu²⁺, Fe²⁺, Na⁺, K⁺, Mg²⁺, Ba²⁺, Ca²⁺, Zn²⁺, Sn²⁺, Pb²⁺, Ag⁺, Al³⁺, Fe³⁺, Ni²⁺, N\begin{array}{c}{O}_2^{-}\end{array}, I\begin{array}{c}{O}_3^{-}\end{array}, Br\begin{array}{c}{O}_3^{-}\end{array}和Cl\begin{array}{c}{O}_3^{-}\end{array}等离子不干扰该电极对汞离子的检测. 此外, 将该电极用于实际水样中微量汞离子含量的测定, 结果与双硫腙分光光度方法一致, 且回收率为98.20%~101.75%.     

A Highly Selective Fluorescent Chemosensor for Cu2+

A new Zn²⁺ probe L2-Zn(L2=naphthofuran carbonylhydrazone derivant) was synthesized as a fluorescence chemosensor for Cu²⁺, by which Cu²⁺ ion could be detected with high selectivity and sensitivity in a wide pH range via a displacement “turn-off” signaling strategy. Whereas the coordination between Zn²⁺ and L2 resulted in a considerable enhancement of typical luminescence of a naphthalofuran group in complex L2-Zn, the addition of Cu²⁺ ion led to a dramatic decrease in the emission intensity of probe L2-Zn at about 503 nm(excitation at 423 nm). The competitive fluorescent experiments showed that other metal ions, such as Hg²⁺, Fe³⁺, Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺ and Mg²⁺ could not impact the detection of Cu²⁺. The detection limit of the novel probe L2-Zn for Cu²⁺ ion was as low as 2.3×10^-7 mol/L, which is far lower than the guideline value of 1.6×10^-5 mol/L of the United States Environmental Protection Agency.