PVC膜pH电极的应用——氢氟酸电离常数的测定

本文制备了以４,４′－－二「（Ｎ,Ｎ′－二癸基氨基）」甲基偶氮苯（ＤＡＭＡＢ）为ｐＨ载体的ＰＶＣ膜ｐＨ电极,该电极在较宽ｐＨ范围内对Ｈ＾＋有较好的能斯特响应,将该电极用于氢氟酸的电离常数测定时,结果良好。     

固体接触型玻璃pH电极的研制

本文采用银导电胶和银丝代替常规ＰＨ玻璃电极的内溶液和内参比。制作固体接触型ＰＨ电极。制作的电极在２－１２ｐＨ范围内呈良好的Ｎｅｒｎｓｔ响应电极的斜率为５８．１ｍＶ／ｐＨ同时还测定了响应时间、温度性能曲线，对实验结果进行了讨论。     

电聚合金属席夫碱配合物修饰电极作为碘离子电位型传感器的研究

本文研究了电聚合金属席夫碱配合物修饰电极对碘离子的选择性响应。Ｃｏ－ｓａｌｅｎ聚合膜电极对碘离子具有良好的电位响应,响应斜率为－７２．５ｍＶ／ｄｅｃ,线性范围为２．０×１０＾－６－１．０×１０＾－１ｍｏｌ／Ｌ,探讨了聚合膜厚度,ｐＨ值对电极性能的影响,同时对电极的响应机理作了进一步的探讨。     

H~＋敏LAPS及其信号检测系统的研制

Ｈ＋敏光寻址电位传感器采用电解质Ｓｉ３Ｎ４－ＳｉＯ２—Ｓｉ结构，取光响应曲线的拐点电位值作为测量ｐＨ的输出参数．整个信号检测和数据处理过程在微处理器控制下实现．传感器的灵敏度为４８ｍＶ／ｐＨ．     

一次性丁氯喘半导体传感器的研究

本文利用场效应晶体管与药物敏感膜相结合，研制成一种ＰＶＣＥ膜丁氯喘半导体传感器，该传感器具有良好的能斯特响应，传感器的丁氯喘的线性范围为５×１０＾－５－１×１０＾－１ｍｏｌ／Ｌ，检测下限７×１０＾－５ｍｏｌ／Ｌ，响应斜率为６０ｍＶ／ｄｅｃ；适宜的ｐＨ范围为２－９。     

金属铱／氧化铱pH电极的研制

本文采用热氧化法制备金属铱／氧化铱ｐＨ电极。电极在２－１２ｐＨ范围内具有良好的Ｎｅｒｎｓｔ响应，２５．０℃下斜率为６０±１ｍＶ／ｐＨ，响应时间小于３０ｓ。电极在不同温度下的斜率接近Ｎｅｒｎｓｔ理论斜率，新鲜电极老化过程中，Ｎｅｒｎｓｔ响庆直线向电位正方向平行漂移，电位漂移速度逐渐减慢至２ｍＶ／２４ｈｒ左右。     

二氧化铱／铱传感器的研制及应用

本文介绍了二氧化铱／铱（ＩｒＯ２／Ｉｒ）ｐＨ传感器的制备方法,探讨了传感器响应的可能机理,考查了该金属氧化物传感器对Ｈ＾＋的响应。实验发现在ｐＨ２．０￣１３．０范围内,该传感器对Ｈ＾＋呈良好的Ｎｅｒｎｓｔ响应,斜率为５６．３３ｍＶ／ｐＨ,ｒ＝０．９９８５。将该传感器应用于酸碱滴定及污水中的ｐＨ测定,均获得满意的结果。     

中性载体PVC膜pH电极的制备与应用

研制了中性载体三辛胺ＰＶＣ膜ｐＨ电极,其响应的ｐＨ线性范围为２．５～１２．３,斜率５３．６ｍＶ／ｐＨ,并用于水样和含Ｆ离子水样ｐＨ测定。     

硼掺杂金刚石薄膜电极电化学特性的研究

本论文以未经任何表面处理的硼掺杂金刚石薄膜为电极材料，应用循环伏安法和计量电流法检测ＫＣｌ和ＨＣｌ－ＫＣｌ底液中Ｋ３Ｆｅ（ＣＮ）６的响应电流，对电极的基本特性如响应时间，稳定性等进行了研究，同时也对溶液ｐＨ值变化所造成响应电流的变化进行了研究。从与玻碳电极比较的角度出发，分别在含有汞的酸性ＫＣｌ－ＨＮＯ３和中性ＫＣｌ体系中，在一定电位下预富集铅，而后用阳极扫描法检测Ｐｂ－Ｈｇ的溶出峰电流，对金刚石     

葡萄糖脱氢酶传感器的研制及应用

本文报道了以甲苯胺兰键合修饰浸蜡石墨电极为基体电极，将葡萄糖脱氢酶（ＧＤＨ），烟酰胺腺嘌呤二核苷酸（ＮＡＤ＾＋）用戊二醛一起固定在蚕丝蛋白膜上，构成葡萄糖脱氢酶传感器。在ｐＨ＝７．４的ＮａＯＨ－ＫＨ２ＰＯ４介质中，该传感器与葡萄糖浓度在２．０×１０＾－５－６．４×１０＾－４ｍｏｌ／Ｌ范围内有良好的线性关系。响应叶间为２０ｓ。本文讨论了影响传感器响应电流的各种因素和测试葡萄糖的最佳条件。用此传感器测     

Novel optical pH sensor for high and low pH values

The development of an optical pH sensor based on immobilization of mixture of two dyes on a triacetylcellulose membrane is described. The sensor has a useful pH range at low and high pH values, where glass electrodes show acidic and alkaline errors, respectively. Application of a back-propagation artificial neural network (ANN) model extends the measuring range of the proposed optode to the whole pH range. The results show very good agreement between true and predicted pH values. The response of the sensor is reversible and reproducible (R.S.D. less than 2%).     

固态pH 探测电极的制备及其性能表征

我们采用熔融碳酸锂(LiCO3)氧化法制备了固态Ir／IrO2 pH电极，同时制备了改进型固态Ag／AgCl参比电极，并对它们的性能进行了表征。实验结果显示，在pH=0-14的溶液中，Ir／IrO2电极与参比电极电位差与pH值呈现良好的线性关系，直线斜率为-62．429mV／pH，截距为607．97mV，相关系数R2=0．993。温度对新型pH传感器响应信号的影响符合Nernst方程，易于进行温度校正。盐度对电信号强度的影响是线性的，在介质盐度已知，或向步测定介质盐度的前提下，可从响应电信号强度及盐度确定待测介质的pH值。     

Optimisation of the range of an optical fibre pH sensor using feed-forward artificial neural network

A broad range of optical fibre pH sensor based on immobilised bromophenol blue (BPB) immobilised on hydrophobic organic polymers Amberlite XAD 7 is presented in this paper. The reflectance spectra of the immobilised bromophenol blue were measured by using an optical fibre spectrophotometer. A back-propagation (BP) artificial neural network (ANN) model was used to analyse the optode response. The results showed that the use of ANN technique was very effective in broadening the limited dynamic response of the pH sensor (pH 2.00–5.00) to an extensive calibration response (pH 2.00–12.00). A network with 11 neurons in the hidden layer was tremendously accurate in predicting the response of the optical fibre pH sensor with an average error 0.02 pH for measuring unidentified buffer solution.     

In-line mixer pH system for the identification of titration curve

An in-line mixer pH system is proposed to identify the titration curve before changes in the input stream affect the main pH neutralization reactor. It is operated under integral control and shows oscillatory responses for a wide range of controller integral gain. The bifurcation diagram for the change of the controller integral gain is very similar to that of the quadratic map which is often used in illustrating the chaos phenomena of nonlinear processes. Various bifurcation diagrams are obtained as operating conditions of the in-line mixer system such as the set point of pH and components of the input stream change. The integral control keeps oscillations be around the set point, providing plentiful information about the pH process. The oscillations can be used to identify the titration curve of the input acid stream. Simulation and experimental results show that the chaotic operations of a small in-line mixer can be positively used for the identification of the titration curve.     

Tuning pH sensitivities of zinc phthalocyanines in ionic liquid modified matrices

Phthalocyanine dyes are clinically important bright fluorophores with many desirable properties. Their absorption and emission maxima in near infrared region make them proper tool for optical probing of biologically relevant materials and optical-chemical-sensing purposes. In this work we have shown that pH sensitivities of the phthalocyanines can be manipulated as desired. This property makes the Pcs very proper photosensitizers for photodynamic therapy applications. In this work pH sensitivities of alpha (α) and beta (β) tetra-substituted zinc phthalocyanines (ZnPcs) were studied spectroscopically in ethyl cellulose and PVC matrices. In experiments designed to manipulate pH, lipophilic room temperature ionic liquids (RTILs) were added into the test environment. The RTIL-modified thin films provided higher relative fluorescence intensity changes upon exposure to proton with respect to the RTIL-free ones. By this way, acidity constants of the ZnPcs could be tuned to the desired region of interest. The ZnPcs, exhibited good reproducibility and reversibility upon protonation. The RTILs also enhanced short and long term stabilities of the Pc-dyes. There was no significant drift in their proton sensitivities even after 10 assays and after being stored in a buffer condition for over six months.     

Optical fiber pH sensor based on lossy-mode resonances by means of thin polymeric coatings

This work describes the fabrication of an optical fiber sensor with spectral response to pH based on the deposition of a thin polymeric coating on an optical fiber core. If the thin polymeric coating has a high refractive index real part and a non-null imaginary part, this permits a coupling of light to the modes guided in the polymeric coating originating optical resonances. These resonances are named by some authors as lossy-mode resonances (LMR) or guided-mode resonances. Moreover, the location of the resonances in the optical spectrum varies as a function of the coating thickness and refractive index. Hence, the utilization of the well-known poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) pH sensitive polymeric coating that presents a variation of the thickness with the pH of the solution (known as swelling/deswelling behaviour) permits the fabrication of optical fiber pH sensors based on wavelength detection. The fabrication of ready-to-use devices requires considering several aspects such as the adequate polymeric coating thickness or the selection of the resonance to be monitored. As a result, LMR-based optical fiber pH sensors with accuracy of ±0.001 pH units and an average sensitivity of 0.027 pH units/nm within the range between pH 3 and pH 6 have been obtained after an adequate design.     

Working with expert systems: Three case studies

Three case studies were conducted on the implications of the use of expert systems for the work of clerks and operators in Britain. An expert system had been introduced in a process control application. The operators' work was deskilled. The second case was a fault diagnosis application. An operator was very happy with his new work. In the third case, insurance clerks received training to operate an expert system which extended the scope of their work. In conclusion, it is suggested that expert systems extend the range of work which can be automated, but may not have unique impacts.     

A novel microfluidic switch for pH control using Chitosan based hydrogels

We report a novel pH-sensitive hydrogel based micro-valve for metered flow that has applications in a laboratory made “Intelligent valving system”. The hydrogel solution was prepared through Chitosan and poly vinyl alcohol in acetic acid and crystallized using gluteraldehyde as the crosslinking agent in the form of thin wafers and it was found to be very sensitive to pH changes. The pore structure of hydrogel was investigated through Field Emission Scanning Electron Microscopy and thin wafers of the gel were physically placed inside PDMS microchannels. Flow metering in these channels was observed by controlled expansion of the hydrogel plug till complete valving was realized. This valving device was further precisely characterized with micro Particle Image Velocimetry using a solution containing fluorescent polymeric micro beads. The principle advantage of this hydrogel device is the smaller range of pH (varying between pH 3 and 7) over which the valving response is observed.     

A new dynamic hydrogen reference electrode for applications in thin-film sensor systems

The realization and applicability of a new dynamic hydrogen reference electrode (DHRE) within an electrochemical microcell for sensor applications is reported. The electrodes are fabricated in thin-film technology and fixed within a flow-through device. An experimental setup for accurate electrochemical potential measurements is described. Smooth platinum, platinized platinum and pHEMA coated electrodes are investigated with regard to their initialization behavior, stability, reproducibility and interference with electrolytes. It is found that platinized platinum DHREs show excellent stability and reproducibility. For uncoated electrodes, the electrochemical potential is established within seconds. The potential is independent of the pH value within the range of pH 4–10. Interference with sulfate and phosphate is observed. Thus, the platinized platinum DHRE is well suited for bioanalytical sensor applications, where the pH value is buffered and the concentrations of the disturbing anions are constant or very low.     

Photon stimulated sensor based on indium oxide nanoparticles I: Wide-concentration-range ozone monitoring in air

Ozone sensors are of great demand for monitoring high-concentration ozone for industrial applications and low-concentration ozone for protecting people's health, although commercial ozone sensors are limited in their detection range. In this work, it is demonstrated that compact energy-saving photostimulated ozone sensors based on indium oxide nanoparticles can detect ozone with a dynamical range over four orders of magnitude at room temperature. The photostimulated ozone sensor shows a very low cross response to NO₂, CO, and CO₂. Furthermore, the sensing signal is very reproducible, and no hysteresis effects were found in repeated measurements.