纳米二氧化锰型固体pH电极的研制及其在含氟腐蚀体系中的应用

1引言酸度的测定在工业、农业、生物、医学、环保等领域有着十分重要的意义,目前广泛采用玻璃电极测量。然而,玻璃电极存在一定的不足,由于它是采用极薄的玻璃膜作为H+的敏感膜,致使玻璃电极极易破碎,难以适宜于强搅拌体系和对玻璃有腐蚀作用的体系,如含氟体系。故多年来对非玻璃型pH传感器的研究一直是个热门的研究课题。其中又以金属/金属氧化物型固体pH电极倍受关注。由于纳米MnO2电极具有较好的pH响应性能,本文利用丝网印刷技术制备了MnO2印刷电极,并研究了此印刷电极在含氟体系pH测定中的应用。2实验方法2．1仪器与试剂φ1…     

基于氮化钛的全固态碱性pH电极的研制

p H值是溶液化学中重要的检测指标 .在工业、农业、生物、医学及环境保护等各个领域都有着广泛应用 .目前 ,多采用玻璃 p H电极进行 p H值的测量 .然而 ,玻璃 p H电极也存在一定的不足 ,玻璃敏感膜阻抗高达 1 0 10 Ω,容易造成电磁干扰 ;玻璃 p H电极极易破碎 ,难以适用于强搅拌的工业过程体系 ;氢氟酸能强烈地浸蚀玻璃膜 .因此 ,玻璃 p H电极不能长时间地用于含氟腐蚀体系 p H的测量 ;另外 ,玻璃 p H电极在强碱性溶液测量时会产生“钠差”.因此 ,多年来对非玻璃型 p H电极的研究一直是化学传感器研究领域中的活跃课题之一 .目前常见的…     

丝网印刷纳米金属氧化物型固态pH电极的研制

近年来对非玻璃型 p H电极的开发一直是化学传感器研究领域中的活跃课题之一 ,其中又以氧化物型的 p H电极倍受关注 [1～ 5 ] .与玻璃电极相比 ,氧化物型的固体 p H电极可呈现出如下的优势 :成本低、响应快、机械强度高 ,且可应用于多种玻璃电极不能适宜的测试环境如高温、强腐蚀或有强制对流等体系 .然而迄今为止 ,已研究过的氧化物种类 (包括 Ir O2 ,Ru O2 ,Pt O2 等 )极为有限 ,且价格较昂贵 .本工作以纳米级的几种过渡金属氧化物 (氧化锰、氧化钴、氧化铅、氧化钛 )为敏感材料 ,利用丝网印刷技术制备了各种氧化物电极 ,对电极的 p H…     

电极/溶液界面pH值的现场测量

一般认为阴极表面功能陶瓷电沉积层的形成是由于基底 /溶液界面化学环境变化造成的 [1,2 ] ,但目前还没有直接的实验数据加以证明 .原位测量电极 /溶液界面 p H的变化存在两方面的困难 :(1 )传统方法是采用玻璃 p H计 ,由于其体积较大、强度脆弱等原因 ,使其在测量固 /液界面化学环境变化的应用方面受到一定限制 [3 ] ;(2 )将 p H微探针置于电极表面 ,将会影响功能陶瓷在电极表面的沉积 ,从而使测定的界面 p H值不能真实反映电沉积过程中固 /液界面化学环境的变化 .本文基于功能陶瓷电沉积过程不受影响的情况下现场直接测量电极 /溶液界面…     

腐蚀介质在缓蚀剂膜中扩散行为的分子动力学模拟

采用分子动力学模拟方法,从缓蚀剂膜阻碍腐蚀介质粒子(H2O、H3O+和HCO3-)向金属表面扩散的角度,研究了4种1-R1-2-十一烷基-咪唑啉缓蚀剂(R1:羧甲基(A),羟乙基(B),氨乙基(C),氢(D))抑制碳钢CO2腐蚀的缓蚀机理,并对其缓蚀性能进行了理论评价.腐蚀介质粒子在不同缓蚀剂膜中的扩散系数、粒子与膜的相互作用能以及膜的自扩散性能的计算结果表明:4种缓蚀剂均可形成稳定的缓蚀剂膜,能有效阻碍腐蚀介质粒子向金属表面的扩散,达到抑制或延缓腐蚀的目的;随亲水支链(R1)极性的增加,缓蚀剂膜对腐蚀介质粒子扩散行为的抑制能力逐渐增强;同种缓蚀剂膜对正负离子H3O+和HCO3-比对中性的H2O分子具有更强的扩散抑制能力.综合计算及分析结果,4种缓蚀剂缓蚀性能的理论评价结果为ABCD,与文献实验结果吻合.     

咪唑啉缓蚀剂膜抑制腐蚀介质扩散行为的MD研究

采用分子动力学模拟的方法,对5种1-(2-氨乙基)-2-烷基-咪唑啉缓蚀剂[(NH2)C2H4-C3H4N2-CH2(CH2)nCH3,n=5,7,9,11,13]抑制CO2腐蚀的缓蚀机理进行了研究.计算了4种腐蚀介质粒子(H2O,H3O+,Cl-和HCO-3)在不同缓蚀剂膜中的扩散系数,并从自由体积分数、腐蚀介质粒子与缓蚀剂膜的相互作用、膜的自扩散性能等方面对缓蚀剂膜抑制腐蚀介质粒子扩散行为的微观机理进行了分析.扩散系数的计算结果表明:缓蚀剂膜能有效抑制腐蚀介质的迁移,削弱其腐蚀能力;与中性H2O分子对比,缓蚀剂膜对H3O+,Cl-和HCO-3带电离子的扩散具有更强的抑制效果;随烷基链长的增加,5种缓蚀剂膜对腐蚀粒子扩散的抑制能力呈增强趋势.综合分子动力学计算结果,5种缓蚀剂缓蚀性能随着烷基链长的增加逐渐增强,理论评价结论与实验结论相吻合.     

三苯基膦中微量氯离子的分离

三苯基膦 [P(C6H5) 3]是一种有机化合物 ,当作为催化剂使用时 ,对其中杂质微量氯离子的含量有严格要求。在用电极法测定其微量氯离子时 ,将氯离子从样品中全部提取是分析结果准确的关键之一。本文讨论了用电极法测定三苯基膦中微量氯离子的分离方法[1] 。1　仪器与试剂p HS- 2型酸度计 (上海第二分析仪器厂 )CT- 1型磁力搅拌器 (北京医用离心机厂 )80 1双液接饱和甘汞电极 (江苏电分析仪器厂 )氯离子选择性电极 (长沙半导体材料厂 )氢氧化钠溶液 :1 0 0 g· L-1硝酸 :0 .2 mol· L-1氯离子储备液 :1 g·L-1硝酸钠溶液 :p H4.0 ,0 .5mol…     

抗坏血酸在2-氨基吡啶修饰电极上的电催化氧化及其应用

研究了 2 -氨基吡啶聚合膜修饰玻碳电极的制备及其电化学性质 ,修饰电极对抗坏血酸 ( AA)的氧化有明显的催化作用 ,其氧化电位负移 2 72 m V。在 p H5 .7的B.R.缓冲溶液中 ,以 1 5 0 m V为工作电位 ,AA在修饰电极上的响应电流与 AA的浓度在 4× 1 0 - 6～ 1 0 - 3 mol/ L范围内呈良好的线性关系 ,检出限为 1 .3× 1 0 - 6mol/ L。在此条件下 ,多巴胺 ( DA)对 AA无干扰 ,电极重现性良好 ,可用于实际样品中 AA的测定     

纳米结构ZnO/染料/聚吡咯光阳极的光电化学性质

用光电化学方法研究了染料RuL2 (NCS) 2 (L =2 ,2′ bipydine 4,4′ dicarboxylicacid) (简写为Dye)、聚吡咯 (PPy)敏化氧化锌 (ZnO)纳米晶电极以及用RuL2 (NCS) 2 和PPy复合敏化ZnO纳米晶膜电极的光电化学行为 .实验表明 ,ZnO/PPy纳米多孔膜电极为双层n 型半导体结构 .PPy和RuL2(NCS) 2 都可对ZnO纳米晶膜产生敏化作用 ,ZnO/RuL2 (NCS) 2 /PPy复合多孔膜电极产生的光电流远大于ZnO/PPy纳米多孔膜电极和ZnO/Dye多孔膜电极产生的光电流 .讨论了该电极的光生电子的机理 ,初步测定了ZnO/RuL2 (NCS) 2 /PPy电极作为光阳极的光电化学电池的工作特性曲线 ,测得该电池的光电转换效率为 1 .3% ,填充因子为 0 .75 .     

纳米Cu_2O材料的合成及其修饰电极安培法测定多巴胺

本文采用简单的一步化学还原方法合成了粒径均一的纳米Cu2O材料并采用扫描电子显微镜对其形貌进行了表征。研究发现,在p H 7.0的磷酸盐缓冲溶液中,采用纳米Cu2O和Nafion(全氟磺酸离子交换树脂)膜制备的复合修饰电极对多巴胺(DA)呈现出较强的电化学催化作用。优化实验条件后,建立了计时电流法直接测定多巴胺的痕量分析体系。在0.5~270μmol·L-1浓度范围内,多巴胺的阳极峰电流与浓度呈良好的线性关系(r=0.9980),检测限为0.17μmol·L-1,灵敏度为20.44μA m M-1且响应时间不超过3 s。该电极可有效屏蔽抗坏血酸(AA)的干扰,在20倍AA共存下仍能准确地测定DA。对含50μmol·L-1DA的溶液平行测定11次,相对标准偏差为3.3%,表明修饰电极的重现性和稳定性好。将该修饰电极用于模拟样品中DA的测定,结果令人满意。     

聚苯胺修饰碳纤维针型复合微pH传感器

由电聚合法用聚苯胺修饰碳纤维电极作为ＰＨ敏感电极。把Ｋ３Ｆｅ（ＣＮ）６／Ｋ４Ｆｅ（ＣＮ）６体系填入医用注射针头内成为参比电极。把经聚苯胺修饰的碳纤维电极安置入该针型参比电极内构成复合针型微ｐＨ传感器。在ＰＨ ２～１２范围内，该传感器呈现超Ｎｅｒｎｓｔ响应，斜率为－７８ ｍＶ／ｐＨ；响应时间<１ｍｉｎ。该传感器成功地应用于在体ｐＨ测定以及水果内微区ｐＨ测定。     

Hydrogen ion-selective poly(vinyl chloride) membrane electrode based on a calix[4]arene.

A hydrogen ion-selective poly(vinyl chloride) membrane electrode was constructed using 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetracyanomethoxycalix[4]arene as a neutral carrier. The electrode showed an apparent Nernstian response in the 2-11.5 pH range with a slope of 54.0 +/- 0.2 mV/pH at 20 +/- degrees C. This electrode showed a rapid response of the emf to changes in the pH, high ion selectivity with respect to lithium, sodium and potassium, and characteristics similar to those reported for the conventional pH glass membrane electrode. It can be used as a potentiometric indicator electrode in hydrofluoric acid solutions. The effects of iodide, thiocyanate, perchlorate and bromide on the characteristics of the electrode were also considered.     

Cesium ion selective electrode based on calix[4]crown ether-ester

The potentiometric response characteristics of cesium ion selective PVC membrane electrode employing calix[4]crown ether-ester as an ionophore were investigated. The electrode exhibit a good response for cesium ion over wide concentration range of 5.0x10(-6)-1.0x10(-1) M with a Nernstian slope of 59 mV per decade. The detection limit of electrode is 5.0x10(-6) M. The electrode was found to have selectivity for cesium ion over alkali, alkaline and transition metals. The response time of the electrode is less than 20 s and can be used for more than 4 months without observing any divergence in potentiometric response. The electrode response was stable over wide pH range.     

Potentiometric determination of acids and bases using a silica gel based carbon-epoxy indicator electrode

The construction and the application of a silica gel based carbon-epoxy indicator electrode for the potentiometric determination of acids and bases are described. The effect of composition of silica gel and carbon-epoxy, slope (mV/pH), linear response (pH range) and the use for acid-base titrations were investigated. The data obtained for the acid-base titrations were compared with those obtained using a glass electrode in the same conditions. The electrode showed a linear response in the pH 2 to 13 range with a slope of –40.5 ± 0.4 mV/pH (at 25 °C) and a response time of less than 15 s. The lifetime of the electrode was higher than one year (over 6000 determinations) with a decrease of only 5% of the initial potentiometric response. The silica gel based carbon-epoxy electrode showed excellent results in the end-point indication potentiometric titrations in determination of acids and bases. The miniaturization of the proposed electrode for flow injection analysis was investigated. Received: 11 August 1999 / Revised: 4 October 1999 / Accepted: 7 October 1999     

All Solid‐State pH Electrode Based on Titanium Nitride Sensitive Film

Titanium nitride was used as pH‐sensitive material to fabricate all solid‐state pH electrode. The fabrication and the response performance of the pH electrode were described in the paper. The TiN film electrode showed a linear response in the pH range of 2–12 with a near‐Nenstian response (?55 mV/pH). The response time was within 1 min, and the electrode had good reproducibility, stability and low sensitivities for different species. Compared with the glass pH electrode, the electrode exhibited some advantages, for example, without activation, rapid response and high mechanical strength. In addition, the electrode performed excellently in a corrosion medium containing F^?(1 M). Electrochemical behaviors of TiN electrode in Britton‐Robinson buffers were studied with Electrochemical Impedance Spectroscopy (EIS).     

聚苯胺/钴-氧化钴膜作传感元件的pH传感器的性能

本文研究了在玻碳电极上修饰不同物质所制得的pH传感器,通过电位滴定的方法比较得出先修饰聚苯胺,再修饰钴-氧化钴膜的电极对pH有较好的响应,能代替玻璃电极应用在实际样品测定中。探究了最佳修饰条件为：先在0.1mol/L苯胺的盐酸（1mol/L）溶液中, 电位范围为-0.2~1.0V,以100 mV/s 的扫描速度循环伏安扫描 10圈修饰聚苯胺膜;接着在含2.0×10-4 mol/LCo2+的PBS （pH=7.5）缓冲溶液中, 电位范围为-1.2~1.2V,以100 mV/s 的扫描速度循环伏安扫描 5圈修饰钴-氧化钴膜。得到的修饰电极响应斜率为-61.60 mV/pH,响应范围pH 0.5~13。     

Tetrakis(4-N,N-dimethylaminobenzene)porphyrinato]manganese(III) acetate as a novel carrier for a selective iodide PVC membrane electrode.

[5,10,15,20-Tetrakis(4-N,N-dimethylaminobenzene)porphyrinato]Mn(III) acetate (MnTDPAc) was applied as an ionophore for an iodide-selective PVC membrane electrode. The influences of the membrane composition, pH of the test solution and foreign ions on the electrode performance were investigated. The sensor exhibited not only excellent selectivity to iodide ion compared to Cl- and lipophilic anions such as ClO4- and salicylate, but also a Nernstian response with a slope of -59.4 +/- 1.2 mV per decade for iodide ions over a wide concentration range from 1.0 x 10(-2) to 7.5 x 10(-6) M at 25 degrees C. The potentiometric response was independent of the pH of the solution in the pH range of 2 - 8. The electrode could be used for at least 2 months without any considerable divergence in the potential. Good selectivity for iodide ion, a very short response time, simple preparation and relatively long-term stability were the silent characteristics of this electrode. It was successfully used as an indicator electrode in the potentiometric titration of iodide ions, and also in the determination of iodide from seawater samples and drug formulations.     

Electropreparation of Poly(benzophenone‐4) Film Modified Electrode and Its Electrocatalytic Behavior Towards Dopamine,Ascorbic Acid and Nitrite

The oxidation of benzophenone‐4 (2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid) at glassy carbon electrode gives rise to stable redox active electropolymerized film during repetitive potential cycling between 0 to 1.3 V (Ag/AgCl). Cyclic voltammogram of poly(benzophenone‐4) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 51 mV/pH. The electrocatalytic behavior of poly(benzophenone‐4) film modified electrode towards oxidation of dopamine, ascorbic acid and reduction of nitrite was investigated. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(benzophenone‐4) film compared to bare glassy carbon electrode. For dopamine, the overpotential was reduced about 180 mV. Feasibility of utilizing poly(benzophenone‐4) film coated electrode in analytical estimation of dopamine, ascorbic acid and nitrite was also demonstrated.     

新型杯芳烃为载体的铅离子选择电极

报道了5,11,17,23-四（1,1-二甲基乙基）-25,27-二羟基-26,28-二[（2-丙酰胺）乙氧基]杯[4]芳烃1的合成及以此化合物为载体研制了PVC膜铅离子选择电极。研究了不同极性的膜增塑剂和亲脂性阴离子位点对铅离子选择电极响应性能的影响,测定了铅离子选择电极的性能。铅离子选择电极对铅离子表现出优良的能斯特响应和高选择性,能在pH4.0-6.5的范围内使用,该电极可作为电位滴定的指示电极。