聚苯胺修饰钨丝针型pH传感器的研究及在河鲫鱼测试中的应用

将聚苯胺修饰的钨丝电极为工作电极,Ａｇ／ＡｇＣｌ电极为参比电极构成针型ｐＨ传感器,该传感器在ｐＨ２～１２范围内呈现Ｎｅｒｎｓｔ响应,响应时间小于１ｍｉｎ,该传感器成功地应用于河鲫鱼由活体到腐败过程中ｐＨ值的变化测定。     

聚苯胺修饰钨丝针型pH传感器的研究及在河鲫鱼测试中的应用

将聚苯胺修饰的钨丝电极为工作电极 ,Ag/ Ag-Cl电极为参比电极构成针型 p H传感器。该传感器在 p H2～1 2范围内呈现 Nernst响应 ,响应时间小于 1 min。该传感器成功地应用于河鲫鱼由活体到腐败过程中 p H值的变化测定。     

钨丝聚苯胺修饰的pH传感器在河鲫鱼分析中的应用(英文)

钨丝聚苯胺修饰的为工作电极,Ag/AgCl为参比电极所构成的pH传感器,在pH2～12范围内呈现Nernst响应,时间小于1min。该传感器从河鲫鱼由活体到一步步腐败的过程中其pH值的变化得到了很好的分析。     

钴酞菁与碳纳米管共修饰碳纤维织物传感器的制备及其电化学性能

为探索钴酞菁(CoPc)/碳纳米管(CNT)柔性葡萄糖传感器在葡萄糖检测中的应用,制备了一种CoPc和CNT共修饰的柔性碳纤维织物(CFT)修饰电极,并利用电化学工作站的银/氯化银参比电极和铂对电极与其共同组成三电极体系的葡萄糖传感器。借助扫描电子显微镜对修饰电极进行表征,采用循环伏安法、电化学阻抗图谱法、时间-电流曲线法研究葡萄糖传感器的电化学性能。结果表明:该修饰电极具有良好的导电性和电子转移能力,葡萄糖检测线性范围为4×10^-3~2.6 mmol/L,检测限为1.4 μmol/L (信噪比为3),灵敏度为231 μA·L/mmol;该修饰电极在检测葡萄糖时具有较好的重复性,测试10次后其响应电流仍可达到初始值的94.6%,且对果糖、蔗糖、乳糖、半乳糖、抗坏血酸、多巴胺、尿酸等物质具有较强的抗干扰性能。     

烟碱PVC膜涂层玻璃电极的研制与应用

以硅钨酸为活性物质，邻苯二甲酸二辛酯为增塑剂，在ｐＨ玻璃电极表面涂敷一层对烟碱敏感的ＰＶＣ膜，构成烟碱选择性电极。在ｐＨ为５～７范围内，该电极对１０－１～１０－５ｍｏｌ／Ｌ的烟碱水溶液有良好的线性响应。以该电极作指示电极，双液接饱和甘汞电极作参比电极，用直接电位法测定了烟草和烟气粒相物中的烟碱含量，回收率在９６．８％～１０３．５％之间。该电极制作简单，选择性好，测定样品时不需将烟碱进行前分离处理，应用方便，与常用的紫外分光光度法相比，分析结果无显著性差异。     

尼古丁针型化学传感器的研制

研制了一种适于尼古丁小体积微量样品快速测定的针型化学传感器。以高分子材料修饰已预处理好的针灸针为基体电极,将含有活性物质硅钨酸的聚氯乙烯(PVC)敏感膜,涂渍于基体电极表面,制成尼古丁针型化学传感器。该传感器在pH4.5～7.0范围内,对5.0×10-5～1.0×10-1mol/L的尼古丁水溶液有良好的线性响应,斜率为57.1mV/dec.,检测下限为1.6×10-5mol/L,响应时间为3min。采用纳米材料SiO2掺杂PVC膜,表明纳米材料SiO2可明显缩短响应时间,提高稳定性,改善传感器的性能。     

重金属离子的聚苯胺修饰印刷电极的脲酶生物传感器检测

利用丝网印刷电极,构建了一种基于聚苯胺膜和壳聚糖的生物传感器,实现了重金属离子的快速检测。聚苯胺膜可通过电聚合修饰在丝网印刷电极表面,对电位变化有明显的响应,可以利用酶抑制作用,检测重金属离子。壳聚糖具有良好的生物兼容性,可以保持脲酶的活性。在最优条件下,用生物传感器检测重金属离子Hg~(2+)和Cd~(2+),重金属离子浓度的对数与抑制率呈良好的线性关系,Hg~(2+)的检出限为3.89μg/L,Cd~(2+)的检出限为5.41μg/L。该传感器用于纺织品样品的检测,加标回收率在88%~111%,可以满足实际检测需求。     

食用盐水溶液pH值的测定

为了消除碘缺乏病 ,使加入食用盐中的碘更加稳定 ,让全国人民吃到合格的碘盐 ,有些生产厂采取加入碱性物质使盐 ｐＨ值控制在一定范围。本方法探讨了食用盐水溶液ｐＨ值的测定 ,更好地指导生产。1　试验方法1 1　原理用电位法测定食用盐水溶液 ｐＨ值 ,是以玻璃电极作指示电剂 ,饱和甘汞电极作参比电报。1 2　仪器、设备1 2 1　ＰＨＳ - 3Ｃ型酸度计或其它型号的酸度计 ,测量范围 0～ 14ｐＨ ,分度值为 0 1ｐＨ单位。1 2 2　指示电极 :玻璃电极。1 2 3　参比电极 :饱和甘汞电极。1 2 4　实验用玻璃水银温度计。1 3　试剂和溶液本方法所…     

基于碳纤维钾离子选择电极的制备及其电化学性能

为实现碳纤维检测汗液中钾离子的新功能并将其应用于智能可穿戴设备中,通过恒电流法将3,4—乙撑二氧噻吩(EDOT)单体原位聚合到碳纤维(CF)上,然后涂覆钾离子选择膜,制备了聚(3,4—乙撑二氧噻吩)(PEDOT)修饰的碳纤维钾离子传感电极,并利用电化学工作站的银/氯化银参比电极与其共同组成2电极体系的钾离子传感器.通过扫描电子显微镜(SEM)、电化学工作站对其物理形貌与电化学性能进行表征.结果表明:经PEDOT修饰的碳纤维电极导电性能显著增强,所制备的钾离子传感器在钾离子浓度为1～32 mmol/L范围内显示出近能斯特响应,灵敏度为52.87 mV/lg[K+],该传感器具有良好的重复性、再现性、长期稳定性,且对钠离子、葡萄糖、多巴胺、尿素具有良好的抗干扰性.     

固体参比电极的使用、检验与维护

固体参比电极是一种比较新型的参比电极。与甘汞电极相比它可省略盐桥而直接插入与锑电极同一介质溶液中进行测量,减少了仪表的日常维护工作量。轻工业部甘蔗糖业科学研究所生产的 pH-2型锑电极发讯器(锑电极采用 Y 型玛瑙刀清擦装置),是采用高纯度金属锑电极与 RE-F_(40)-1型     

Measurements of pH(60) in pork using ISFET/REFET and glass electrode methods

pH values of 180 pork longissimus dorsi muscles were obtained using different measurement methods. A glass combined penetration electrode and an ISFET/REFET pH sensor system were used directly in the muscle, whereas in the homogenate, pH was assessed with a glass combined electrode. The results showed that no statistically significant differences were obtained between the methods in all tested samples. However, samples where pH(60) stood below 5·9, produced a better agreement between methods. Comparing the values obtained from the two direct puncture methods in the first group of samples (pH<5·9) the I/R probe appeared to agree with those obtained from the homogenates. While working, the ISFET/REFET system proved to be a good device to detect carcasses with fast post mortem pH decline. Nevertheless, the excessive time required display stabilisation prohibits its use for continuous measurements on high speed slaughter-lines.     

Electrochemical sensor detecting free sulfhydryl groups: evaluation of milk heat treatment

We describe a new and rapid method for the evaluation of reactive sulfhydryl groups in whey proteins obtained after precipitation of casein by acetic acid at pH 4.6. The procedure is based on the use of a wire tungsten electrode operating at -0.2 V versus saturated calomel electrode in flow injection analysis. The method was applied to raw milks and to commercial pasteurized and UHT milks. Results showed that the tungsten electrode constituted a robust amperometric sensor that could be used to differentiate milks that underwent different heat treatments. The decrease of thiol content in the whey proteins from samples was in agreement with the whey protein content found by HPLC. The procedure is suitable for on-line quality control of heat-treated milks.     

L-半胱氨酸聚合膜亚硝酸盐安培传感器的制备及在食品检测中的应用

将L- 半胱氨酸通过循环伏安法电聚合到玻碳电极表面,制备了一种聚合物薄膜修饰电极,构建了一种新型NO2 安培传感器。实验结果表明,NO2 在该传感器上表现出良好的安培响应。其稳态电流与NO2 的浓度在1.0 × 10-6～4.4 × 10-5mol/L 范围内呈现良好的线性关系,检测限为1.0 × 10-7mol/L。此传感器具有灵敏度高、检测限低、抗干扰能力强等优点,应用于食品中NO2 含量的测量,结果满意。     

A novel potentiometric pH electrode based on sulfated natural Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> and analytical application in food samples

A novel solid state potentiometric pH electrode based on sulfated natural Fe₃O₄ silicone was fabricated. The optimum potentiometric performances such as Nernstian response, response time, selectivity, life-time and reproducibility of pH electrodes were investigated by using a computer-controlled potentiometric device. Moreover, the potentiometric performance of the solid state pH electrodes was studied with different mixtures sulfated natural Fe₃O₄, silicone and graphite powder. The best potentiometric behavior of proposed pH electrode was obtained with a composition of 20% (w/w) sulfated natural Fe₃O₄, 40% (w/w) graphite powder and 40% (w/w) silicone. The sub-Nernstian response for pH electrode was exhibited with a slope of 30.8?±?1.4 mV/pH (r?=?0.9963) from pH 2 to pH 12. In addition, the dynamic response time was found as 10 s in acidic medium and further the proposed pH electrode can be used for at least 1 year without any significant slope of the pH–potential curve. The selectivity coefficient of pH electrode was interpreted according to fixed interference method in the presences of Na⁺, Li⁺, K⁺, NH₄⁺, SO₄^2?, CH₃COO^? and NO₃^? ions. The reproducibility of pH electrode was calculated in pH 4 and pH 6 phosphate buffers and it was found as 0.24 RSD (%) and 0.27 RSD (%) respectively. The proposed pH electrode was used to determine of pH in acid?bases titration compared with glass pH electrode and is highly stable in corrosive systems including HF solution. Terminally, the pH value was successfully determined in some soft drinks and milk samples by proposed solid state pH electrode at 95% confidence level with satisfactory agreement compared with glass pH electrode.     

Potentiometric Determination of Aluminum in Foods, Pharmaceuticals, and Alloys by AlMCM-41-Modified Carbon Paste Electrode

A new chemically modified electrode is constructed by incorporating AlMCM-41 into carbon paste matrix (AlMCM-41-MCPE) and used as a sensitive sensor for detection of aluminum in aqueous and nonaqueous solutions. The rapid exchange kinetics in the membrane results in a near-Nernstian behavior of the modified electrode and makes it a suitable potentiometric sensor for detection of aluminum. A linear response in concentration range from 1.0?×?10^?6 to 1.0?×?10^?1 mol/L (0.027 μg/mL–2.7 mg/mL) was obtained with a detection limit of 4.6?×?10^?7 mol/L for the potentiometric detection of aluminum. Selectivity coefficients of a number of interfering cations have been estimated. The interference from many of the investigated ions is negligible. The AlMCM-41-MCPE is suitable for use in aqueous solution of pH 2–6 and in partially nonaqueous medium. The modified electrode exhibited a fast response time (~8 s), good stability, and an extended lifetime. The developed sensor was used successfully for the determination of Al³⁺ in some alloys, drugs, and food products.     

High-performance planar pH fluorosensor for two-dimensional pH measurements in marine sediment and water

A new plate fluorosensor foil was developed for two-dimensional pH measurement in marine sediments and overlying waters. The fluorescent dye 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) was covalently linked onto a transparent poly(vinyl alcohol) membrane backed by polyester sheet. Both excitation and emission bands of the immobilized HPTS showed large red shifts in comparison to HPTS in free solution. The ratio of fluorescence emission intensities at 540 nm following successive excitation at 506 and 428 nm was pH-sensitive and correlated with pH changes from 5.5 to 8.6. These properties are robust and insensitive to factors such as intensity of light source, temperature, and oxygen concentration. The plate sensor responded rapidly (< 2 min), reversibly, and with high precision to pH changes in solution and in sediment. The stability of the sensor was also tested by continually changing the pH between 6 and 8. Performance of the sensor did not vary after > 200 pH cycles. Furthermore, the sensor foil retained its original properties after continuous exposure to natural marine sedimentfor 2 months. The plate optode has been successfully used to measure two-dimensional pH distributions in intertidal flat and subtidal sediment. Images are readily obtained with inexpensive light-emitting diode (LED) excitation and commercial-grade digital cameras with typical pixel resolution of approximately 50 x 50 microm over areas > 150 cm2.     

Evaluation of primary models to describe the growth of Pichia anomala and study of temperature, NaCl, and pH effects on its biological parameters by response surface methodology

Tolerance of Pichia anomala, a strain of yeast associated with olive fermentation, to salt, temperature, and pH was studied in yeast-malt-peptone-glucose medium using a nonfactorial central composite experimental design with three repetitions in the center to account for pure error. Modified Gompertz, logistic, Richards-Stannard, and Baranyi-Roberts models were used to determine maximum specific growth rate (micro(max)) and lag phase period (lambda) from the growth curves (primary models). All models produced a good fit (significant at P < 0.05), but the graphical and statistical analyses of the data indicated that the modified Gompertz and Richards-Stannard models were the most appropriate. The biological parameters obtained with the diverse models were fitted to a response surface secondary model. A significant decrease in micro(max) was observed as temperature decreased and salt increased. A significant increase in lambda was observed as temperature (linear and quadratic effects) and pH decreased and as salt content increased. Effects of interactions were complex and depended on models. Validation revealed acceptable errors and bias in micro(max) and lambda values obtained in independent experiments. Validation growth curves were best reproduced by using the values of micro(max) and lambda predicted by the response surface from the modified Gompertz and Richards-Stannard models. Results from this study can be applied to table olive fermentation or storage and for production of table olives as refrigerated commercial products without the use of preservatives or pasteurization.     

联苯三唑醇分子印迹电化学传感器的制备及识别性能研究

以联苯三唑醇为模板分子,通过电聚合邻苯二胺,在玻碳电极表面制备了对模板分子具有特异识别的分子印迹电化学传感器。实验选用铁氰化钾(K3[Fe(CN)6])作为电活性探针,采用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了该传感器的电化学特性,并且优化了制备条件,研究了印迹传感器对模板分子及其结构类似物的选择性响应。结果表明:在最佳聚合条件下,p H=7.2,模板分子:功能单体=1:4(c/c),聚合圈数15圈,洗脱时间为13 min,洗脱剂:0.5 mol/L硫酸:乙腈=1:9(V/V),连续洗脱10次之后,相对标准偏差为5.2%,且传感器性能无衰减现象。该分子印迹电化学传感器灵敏度高,抗干扰能力强,对联苯三唑醇及其结构类似物具有良好的选择性响应,可以对结构类似物分别进行测定,为快速检测食品中联苯三唑醇奠定了基础。