汞离子选择电极在海水痕量元素检测中的应用

由于自由汞离子(Ⅱ)在低浓度时不易保持其形态,在此以汞络合平衡的基本原理为基础,计算并讨论了汞在溶液体系中的存在形态,从而获得稳定的低浓度自由汞离子以及溶液中自由汞离子浓度和总汞浓度之间的关系.通过对汞离子选择电极(Hg-ISE)在类似海水的缓冲溶液体系实验测试及分析,其结果显示在自由汞离子浓度高于10-19 mol/L时,总汞浓度和自由汞浓度仍然保持成一定的线性关系,表明可以通过检测自由汞离子浓度来检测海水中总汞浓度.     

基于电化学寡核苷酸传感器的痕量汞离子检测

水环境中的重金属汞污染日益严重,对生态环境和人类健康造成了不容忽视的威胁。因此,现场监测痕量汞离子具有极其重要的意义。构建了一种基于胸腺嘧啶-Hg^2+-胸腺嘧啶(T-Hg^2+-T)特异性配位结构的无标记型电化学寡核苷酸传感器,用于检测痕量Hg^2+。将末端修饰巯基的富T寡核苷酸链(Oligo)自组装到金电极表面,当存在Hg^2+时,Oligo探针将捕获Hg^2+而发生构象变化,形成"发卡型"结构。利用电化学阻抗谱对金电极表面自组装膜的构象变化进行表征,发现电子转移阻抗RCT随Hg^2+浓度的升高而减小,建立两者间的线性关系,从而实现对Hg^2+的定量检测。本传感器在0.5 nmol/L^500 nmol/L范围内具有良好线性关系,检出限为0.2 nmol/L,特异性实验表明该传感器对Hg^2+选择性极好。该传感器为水环境中痕量汞离子的准确、定量检测提供了一种有效的手段。     

卟啉枝接联吡啶用于高选择性铜离子荧光传感器的研究

该文合成了一种金属卟啉化合物,即酰胺键联接的四苯基卟啉锌和联吡啶(ZnTPPBPy),并首次将其用于识别二价铜离子.其中四苯基卟啉锌作为荧光基团,联吡啶作为识别基团.联吡啶与铜络合以后,通过光致电子转移过程,猝灭四苯基卟啉锌的荧光,这为铜离子荧光传感器的构建提供了理论基础.考察了该铜离子化学传感器的响应特性.铜离子响应的线性范围为3.2×10-7 ～1.0×10-5 mol/L,工作曲线的回归方程为log(△F/F)=9.639 1.757 log[Cu2 ].实验结果表明,在过渡金属阳离子中,除了汞离子有轻微干扰外,该传感器对铜离子具有良好的选择性.     

基于离子电流的高温压力传感器机理研究

研究基于离子电流的高温环境压力传感器,旨在替代带冷却设备的高温压力传感器,为脉冲爆震发动机(PDE)上必需的高温压力测量提供具有工程实践意义的技术支持,为爆震发动机性能分析、控制规律和控制策略研究提供可靠的测试信号。通过2种类型离子探针的对比分析和探针长度、偏置压力的研究,设计了一种单针短探针型离子传感器,其离子电流信号波形与压力传感器信号相似,离子电流衰减速度可测,耐高温,可靠性高,成本低。为研究离子电流与压力的定量关系奠定了基础。     

共轭导电聚合物及其在传感器中的应用

分析了共轭导电聚合物的结构特征和导电机理，综述了共轭导电聚合物在离子传感器、气体传感器、湿度传感器和生物传感器中的应用和原理，并展望了共轭导电聚合物在传感器中的研究方向和应用前景。     

用于环境检测的电子舌研究

介绍我们在用于环境检测中的电子舌方面的研究研制的几种新型的离子传感器,包括基于表面光伏技术的集成离子传感器、光化学原理的集成光学离子传感器阵列,其特点是采用硅微加工技术实现微结构离子器件的研制.介绍了电子舌中采用的信号处理和模式识别技术和我们研制的新型的用于海洋环境检测电子舌仪器.最后给出了电子舌用于环境检测的一些实验结果.     

航空发动机加力火焰检测的试验验证

为了准确获取航空发动机加力燃烧室火焰燃烧情况进行推力控制，针对航空发动机控制系统中加力火焰检测的作用，分析了基于离子火焰传感器的加力火焰检测工作原理。根据离子火焰传感器在航空发动机中的实际安装情况，分析提出了影响加力火焰检测的因素，包括离子电流的汇流面形状、离子火焰传感器电极与汇流面的相对距离、燃烧温度以及离子火焰传感器电缆的寄生电容。通过搭建燃烧试验平台进行试验，验证了离子火焰传感器在航空发动机实际安装使用中各影响因素对离子火焰传感器采集值影响趋势，试验结果可用于航空发动机加力状态检测相关故障的排查。     

快速响应的LaF3基质氧传感器

利用ＬａＦ３单晶（氟化物离子导体）和酞菁铅作传感器材料，制作了在室温下工作的固体电解质氧化感器，传感器的电动势稳定地随氧分压的改变而变化，其特征是氧分子的双电子还原反应，而且传感器的９０％响应时间在３０℃时为３０秒。     

氟离子敏场效应管的研制

阐述了一种氟离子敏场效应晶体管(FISFET)型传感器的结构和工作原理。它是在pH ISFET传感器的基础上用PVC方法把离子敏场效应晶体管和氟化物敏感膜相结合,制成氟离子敏场效应晶体管。该传感器具有全固态化 体积小的特点。实验表明该传感器的灵敏度为50mV/C,响应时间:小于1min,相关系数为0.9842,对氟化物的检测范围:1×10-6～1×10-1mol/L。     

传感器─电话系统在火灾报警中的应用

介绍一种火灾自动报警系统。该系统应用了离子感烟传感器和电话。当发生火灾时传感器检测出信号 ,通过控制电路使电话自动拨号 (如 119) ,并报告现场地址     

Shrink-induced ultrasensitive mercury sensor with graphene and gold nanoparticles self-assembly

Here we report an ultrasensitive trace mercury(II) micro sensor based on heat-shrinkable polymer (polyolefins, PO). The layer-by-layer self-assembly (LBL SA) method was employed to modify mixed gold nanoparticle (Au NPs) and graphene solution on a micro gold electrode with PO substrate. The unique wrinkle structure of the electrode surface and superior properties of modification film enhanced the performance of LBL SA graphene–Au NPs shrink sensor greatly in determination of Hg(II) using anodic stripping voltammetry (ASV): compared with a shrink gold electrode without surface modification, the sensitivity was improved for about 3.7 times from 0.197 to 0.721 μA/ppb; compared with a same-sized sensor without surface modification nor shrink, the sensitivity was improved for over 50 times. This sensor’s detection limit of Hg(II) was achieved as 0.931 ppb with a sensitivity of 0.721 μA/ppb. This simple but highly sensitive sensor can be widely used in applications of on-line environmental monitoring of Hg(II).

     

Development of a mercury optical sensor based on immobilization of 4-(2-pyridylazo)-resorcinol on a triacetylcellulose membrane

A new optical sensor for mercury(II) ions is developed based on immobilization of 4-(2-pyridylazo)-resorcinol (PAR) on a triacetylcellulose membrane. Chemical binding of Hg²⁺ ions in solution with a PAR immobilized on the triacetylcellulose surface could be monitored spectrophotometrically at 525 nm. The optode shows excellent response over a wide concentration range of 5–3360 μM Hg(II) with a limit of detection of 1.5 μM Hg(II). The influence of factors responsible for the improved sensitivity of the sensor were studied and identified. The response time of the optode was 20 min for a stable solution, and was 15 min for a stirrer solution. The influence of potential interfering ions on the determination of 5 × 10⁻⁵ M Hg(II) was studied. The sensor was applied for determination of Hg(II) in water samples.     

An adsorption-based mercury sensor with continuous readout

A novel readout procedure for a mercury sensor has been proposed. The sensor is based on the surface adsorption. Mercury vapor is adsorbed at the surface of a thin gold layer patterned into four meanders which are connected into a Wheatstone bridge configuration. Sensing is achieved by the resistivity change of the gold film during mercury adsorption. Direct output from the sensor is electric voltage. It takes an additional procedure to convert voltage to mercury concentration. This type of sensor is improved by introducing continuous readout procedure for the voltage–concentration conversion. By using this readout procedure it is possible to monitor mercury vapor concentration as a function of time. Readout is based on the Langmuir time–dependent adsorption theory. This paper illustrates a practical implementation of the new readout procedure.     

Ultra trace mercury(II) detection by a highly selective new optical sensor

This paper presents the development and construction of a sensitive new optical sensor that is highly selective to Hg²⁺ ion in aqueous solution. The sensing element, the newly synthesized (1Z,2Z)-N′¹,N′²-dihydroxy-N¹,N²-dipyridin-2-ylethanediimidamide, incorporated into a plasticized poly(vinyl chloride) membrane, is capable of determining mercury(II) with a high selectivity over a wide dynamic range from 5.78 × 10⁻⁹ to 1.05 × 10⁻³ M at pH 4.0 with a lower detection limit of 1.71 × 10⁻⁹ M. The optode membrane's response to Hg²⁺ is fully reversible and reveals a very good selectivity towards Hg²⁺ ion over a wide variety of other metal ions in solution. Performance characteristics of the sensor evaluated as good reversibility, wide dynamic range, long life span, long-term response stability, and high reproducibility. The proposed optical sensor gives good results for applications in direct determination of mercury(II) in environmental real samples that are satisfactorily comparable with corresponding data from cold-vapor atomic absorption spectrometry.     

Development of a highly sensitive and selective optical chemical sensor for batch and flow-through determination of mercury ion

A very sensitive, highly selective and reversible optical chemical sensor (optode) for mercury ion is described. The sensor is based on the interaction of Hg²⁺ with 2-mercapto-2-thiazoline (MTZ) in plasticized PVC membrane incorporating a proton-selective chromoionophore (ETH5294) and lipophilic anionic sites (sodium tetraphenylborate, NaTPB). The membranes were cast onto glass substrates and used for the determination of mercury ion in aqueous solutions by batch and flow-through methods. The sensor could be used in the range 2.0 × 10⁻¹⁰ to 1.5 × 10⁻⁵ M (0.04 ng mL⁻¹ to 3 μg mL⁻¹) Hg²⁺ with a detection limit of 5.0 × 10⁻¹¹ M and a response time of <40 s. It can be easily and completely regenerated by dilute nitric acid solution. The sensor has been incorporated into a home-made flow-through cell for determination of mercury ion in flowing streams with improved sensitivity, precision and detection limit. The sensor showed excellent selectivity for Hg²⁺ with respect to several common alkali, alkaline earth and transition metal ions. The results obtained for the determination of mercury ion in river water samples using the proposed optode was found to be comparable with the well-established cold-vapor atomic absorption method.     

Environmentally friendly disposable sensors with microfabricated on-chip planar bismuth electrode for in situ heavy metal ions measurement

This paper presents an environmentally friendly disposable heavy metal ion sensor for in situ and online monitoring in the nature and physiological systems. The miniaturized sensor chip consists of a non-toxic microfabricated bismuth (Bi) working electrode that replaces the conventional mercury electrodes, an integrated Ag/AgCl reference electrode, a gold counter electrode, and microfluidic channels. In this work, the electrochemical behavior of the Bi working electrode was characterized in several non-deaerated buffer solutions using cyclic voltammetry. The detection and quantification of Pb (II) and Cd (II) were statically performed using anodic stripping voltammetry inside the microchannels, in the Pb (II) concentration range of 25–400 ppb (R² = 0.991) with limit of detection of 8 ppb for 60 s deposition, and in the Cd (II) concentration range of 28–280 ppb (R² = 0.986) with limit of detection of 9.3 ppb for 90 s deposition. Particularly, the applications of this sensor chip have been reported with the examples of in situ measurement of Cd (II) concentration in soil pore and ground water and online direct measurement of Cd (II) concentration in cell culture media in its native environment.     

基于水银开关的矿用本安型堆煤传感器的设计

针对基于行程开关的堆煤传感器由于行程开关易受煤尘侵扰、潮气锈蚀等外部环境的影响而常常不能及时准确地监测到堆煤故障信号的不足,提出了一种基于水银开关的新型矿用本安型堆煤传感器的设计方案。该传感器利用水银开关的原理,在煤刚开始堆积时就将该故障信号传送至胶带输送机保护控制系统,防止煤炭持续堆积,达到保护胶带的效果。实际应用表明,该传感器运行稳定,可靠性高。     

A polymer lab chip sensor with microfabricated planar silver electrode for continuous and on-site heavy metal measurement

This paper presents a reusable polymer lab chip sensor for continuous and on-site heavy metal monitoring in nature. In particular, detection of lead (Pb(II)), which is the most common heavy metal pollutant, has been performed using the proposed lab chip sensor. The miniaturized lab chip sensor consists of a microfabricated silver working electrode that replaces the conventional mercury and bismuth electrodes, an integrated silver counter and quasi-reference electrode, and microfluidic channels. The proposed sensor targets on-site environmental monitoring in a continuous fashion without disturbing or contaminating the sensing environment when it is reused. The reusability of the miniaturized lab chip sensor was characterized through forty-three consecutive measurements in non-deoxygenating standard solutions inside the microchannels using square-wave anodic stripping voltammetry (SWASV). With only 13.5 μL of sample volume the sensor chip showed a correlation coefficient of 0.998 for the Pb(II) concentration range of 1-1000 ppb with the limit of detection of 0.55 ppb at 300 s deposition time. The peak potentials during the forty-three consecutive SWASV measurements showed a relative standard deviation of 1.0%, with a standard deviation of 0.005 V. The high repeatability and linearity of the sensor over the large, three orders of magnitude, dynamic range of 1-1000 ppb showed that the developed sensor chip can be reused for a variety of on-site measurements such as for soil pore water or groundwater, using only micro-volumes.     

基于ADXL335的堆煤传感器的设计

针对基于行程开关的堆煤传感器监控信号不准确以及基于水银开关的堆煤传感器无法灵活设置动作点(倾斜角度)的局限性,提出了一种基于ADXL335三轴加速度计的新型矿用堆煤传感器的设计方案,介绍了该传感器主要电路的设计。该传感器利用加速度计的三轴角度测量功能,实现了全方位高精度测量,能将信号及时准确地传送至胶带输送机保护控制系统,防止了煤炭的持续堆积。     

Preconcentration and voltammetric analysis of mercury(II) at a carbon paste electrode modified with natural smectite-type clays grafted with organic chelating groups

This study is devoted to the evaluation of a carbon paste electrode modified by a natural 2:1 phyllosilicate clay functionalized with either amine or thiol groups as a sensor for mercury(II). Functionalization was achieved by grafting the pristine clay via its reaction with 3-aminopropyltriethoxysilane (APTES) or 3-mercaptopropyltrimethoxysilane (MPTMS), respectively. The electroanalytical procedure comprises two steps: the chemical accumulation of the analyte under open-circuit conditions followed by the electrochemical detection of the preconcentrated species using differential pulse anodic stripping voltammetry. The different parameters that govern the two steps (accumulation time, concentration of the analyte, composition of the detection medium, potential and duration of electrolysis) were studied in detail. After optimization, a linear response was obtained in the concentration range from 0.1 to 0.7 μM Hg(II). In these conditions, the detection limits of the method were found to be 8.7 × 10⁻⁸ and 6.8 × 10⁻⁸ M, respectively, for the amine- and thiol-functionalized clays, on the basis of a signal-to-noise ratio of 3. The effect of potential interference on the determination of Hg(II) by the carbon paste electrode modified with the thiol-functionalized clay was also studied and the applicability of the method to real sample analysis was evaluated.