碳纤维微电极吸附溶出法分析痕量核酸

本文介绍了碳纤维超微电极吸附溶出电位法分析痕量ＤＮＡ和ＲＮＡ的方法。碳纤维的来源对痕量核酸测定有较大影响,其中以“Ａｅｓａｒ”材料进行痕量核酸测定效果最好。碳纤维超微电极 可有效只附富集静置微升量溶液中ＤＮＡ和ＲＮＡ,在吸附溶出转移实验中效果良好。文中描述了表面邓处理和富集条件的影响并对分析效能特性进行了讨论。富集５ｍｉｎ后测定,ｔＲＮＡ、ｓｓＤＮＡ、ｄｓＤＮＡ的检测限分别为６、１５、４０ｕｇ／Ｌ     

金膜电极微分电位溶出法测定食品中的砷

目的:建立一种测定干制食品中砷的快速测定方法。方法:干制食品经混合酸硝化后,将As(Ⅴ)还原成有电活性的As(Ⅲ),在硫酸介质中,用金膜电极为工作电极进行微分电位溶出分析,依据溶出峰值(dt/dE)与被测离子浓度成正比的关系定量。结果:在2.0mol/L H2SO4介质中砷可在镀金膜电极上得到灵敏的微分电位溶出峰(E=-0.19 V),检测下限为0.1μg/25mL,对样品中的砷进行测定,相对标准差:3.1%~5.6%,加标回收率:96.2%~108.1%。结论:方法灵敏、简便,能用于干制食品中微量砷的快速测定。     

应用电位溶出法测定化妆品中铅

采用电位溶出法测定化妆品中铅,样品经过湿法消化,适当稀释即可直接测定。该方法操作简单、快速、干扰少,具有灵敏度高、重现性好等优点。实验结果与双硫腙比色法对同一样品测定结果做统计处理,无显著性差异。     

计算机控制恒电流／电位溶出仪用于痕量锡的分析

电化学分析法已广泛用于锡的测定,其中阳极溶出伏安法和极谱催化波具有较高的灵敏度。Florence等人应用电分析法测定了海生动物和食品中的微量锡,该法采用氢氧化铁共沉淀富集水中的锡,再用蒸馏法以四溴化锡形式分离出锡。电位溶出法具有快速、灵敏和仪器简单等特点,既可用于痕量金属离子的检测,也可用于环境样     

用C语言编写的电位溶出分析程序

介绍了用Ｃ语言编写的电位溶出分析程序;说明了基本思路、关键方法和程序功能,以帝例说明所编程序的应用是成功的。     

球形镍金基体真空镀汞膜电极的研制及性能测试

研制了一种球形镍金基体真空镀汞膜电极。采用2．5次微分极语法对电极性能进行了考查,在0.1MKCl中,镉的线性范围为4×10~(－8)－6×10~(－11)M,证明该电极性能稳定,灵敏度高,重视性好。     

便携式微机化电位溶出分析仪的研制

本文介绍便携式微机化电位溶出分析仪的硬件和软件结构。仪器采和单片机为核心组成控制及测量系统，简化接口电路，改由传统的人工模拟调节方式为计算机数字调节方式。通过电子开关电路进行检测过程中电路的高速切换，增设多扫描技术，强化检测功能，实现室外现场元件的自动分析，实现了仪器与ＰＣ机联机通讯，进行分析曲线的静态和动态显示，以及复杂的数据和结果处理。     

基于虚拟仪器技术的微分电位溶出分析仪的研制

虚拟仪器技术是电子测量技术与计算机相融合的一项测控领域的新技术.文中提出了一种基于虚拟仪器技术的微分电位溶出分析测试仪器.在简要介绍其工作原理的基础上,详细论述了其软、硬件实现方法.利用labVIEW作为开发平台,完成了分析测试仪的程序设计.在数据处理上,利用LabVIEW三次样条插值函数,用软件的方法替代硬件微分电路,实现了数值微分算法在分析测试仪上的应用.测试分析仪前面板设计有用户选项,通过设置,能够自动完成不同元素的测试及其数据分析,给现场测试带来方便.     

微机控制的流动注射—电位溶出分析系统的研制与应用

本文采用自制的EA-1型微机化多功能电化学分析仪控制FIA-21A型流动注射分析仪,设计了碳纤维电极微型流通池,编制了流动注射—电位溶出分析软件,实现了流动注射—电位溶出自动分析。本文设计的软件具有很大的灵活性,选择不同的左右泵转,停次序和不同长短的转停时间,不同的施加电解电位的时刻和时间,以及不同的阀进样时刻,可组合成多种分析模式,便于采用流动注射法的介质交换技术停流技术、间歇泵技术、合并带技术和区域采样技术等等。本文还设计了一个流动系统测试程序,用电化学方法测试样品带在流动系统中的浓度分散曲线及停留时间等参数。系统初步应用于水样中Cd、Pb 的同时测定,取得了满意的结果。     

多项式滤波及数值微分方法在微分电位溶出分析中的应用

文章就信号处理中常用的多项式最小二乘法滤波及如何实现数字信号的数值微分方法做了介绍 ,并讨论了其在微分电位溶出分析仪上的应用     

原子荧光光度法测定地表水中的痕量汞

以硫酸-高锰酸钾加热消解水样,低浓度硼氢化钾作为还原剂,运用 A FS -9230双道原子荧光光度计,采用顺序注射-冷蒸气发生-原子荧光光谱法,测定地表水中的痕量汞。检出限为0.012μg/L ,回收率为90％～110％,RSD小于10.0％,该法具有灵敏度高,精密度好,干扰少和操作简单方便等优点,同时对方法的质量控制进行了探讨。     

水质铅自动在线监测仪测定水样中铅的含量

首先,构建了基于聚苯乙烯-双硫腙纳米纤维的铅离子富集前处理装置,可以有效地降低铅的检出限并提高检测灵敏度和选择性。其次,研发了水质铅自动在线分析监测仪,以预镀汞膜的玻碳电极为工作电极,采用阳极溶出伏安法,对实验参数进行了优化,例如预镀汞膜的条件、缓冲液的种类和浓度、铅富集时间和电压等。在最优化条件下,铅的溶出峰面积与其浓度在0～2000μg/L 范围内呈现良好的线性关系,其回归方程为 y1＝-0.07843＋0.00269 x （相关系数为0.998,浓度范围为5～2000μg/L ）,y2＝-0.0035＋0.00178 x （相关系数为0.998,浓度范围为5～100μg/L ）,检出限为0.38μg/L。在此基础上,采用标准加入法对水样中铅的含量进行了测定,并与原子吸收法的测定结果进行了比较。结果显示,该水质铅自动在线监测仪具有快速、准确、简便、灵敏等优点。     

Determination of haloperidol drug in ampoules and in urine samples using a potentiometric modified carbon paste electrode

A modified carbon paste electrode for haloperidol drug based on haloperidol-phosphomolybdate (HP-PM) as an ion-exchanger dissolved in plasticizer DBP and its potentiometric characteristics were discussed. The electrode exhibited a good Nernstian slope of 56.9 ± 0.3 mV/decade with a linear concentration range from 3.2 × 10⁻⁶ to 1.0 × 10⁻² M for the haloperidol ion. The limit of detection (LOD) was 1.5 × 10⁻⁶ M. It had response time of 5–8 seconds (s), useable in pH range of 6.2–8.6 and temperature of 20–60 °C. The electrode shows clear discrimination of haloperidol drug from several inorganic ions, sugars and some common drug excipients. The sensor was applied for determination of haloperidol drug in urine and in pharmaceutical formulations using potentiometric determination, standard addition and the calibration curve methods. The results are satisfactory with excellent percentage recovery comparable or better than those obtained by other routine methods.     

金属表面润滑膜形成的化学特性研究

金属表面形成的化学吸附膜的质量与诸多因素有关,其中影响最大的基本要素是水、氧化物,如何控制水和氧化物的含量、成分是化学吸附膜形成质量的保证。本文从金属及润滑油膜的化学特性角度出发,对其形成原理,与水、氧化物之间相互作用关系进行研究。同时论述了润滑油膜最有效的测定方法——表面电位测定法原理,对深入了解各种润滑油膜吸附机理提供理论参考。     

Determination of the carcinogenic potential of lubricant base oil using near infrared spectroscopy and chemometrics

In the present study, near-infrared (NIR) spectroscopy and chemometrics techniques have been combined to predict the carcinogenic potential of lubricant base oils. Principal component analysis was used to select the relevant wavelengths of the NIR spectra and principal component regression was employed to develop linear models to predict the total polyaromatic assay (IP 346) and the mutagenicity index (ASTM E1687/95) of lubricant oil samples. The good correlation between NIR normalised spectra (r=0.995; RMSEP=0.4%) and the total polyaromatic assay is discussed. It was concluded that the combination of both techniques could be used for the on-line determination of the carcinogenic potential of lubricant oils.     

“Pull-in” of a pre-stressed thin film by an electrostatic potential: A 1-D rectangular bridge and a 2-D circular diaphragm

A one-dimensional (1-D) rectangular pre-stressed thin film clamped at two opposite ends is actuated by an electrostatic voltage applied to a pad directly underneath. The pre-stress is allowed to be either tensile or compressive in nature. At a critical applied voltage, the film becomes unstable and makes direct contact with the pad, leading to “pull-in”. An elastic model is constructed to account for the phenomenon over ranges of film-pad gap and residual stress. The results compare favorably with finite element analysis (FEA) in literature and experimental data, and possess distinct advantages over other available closed-form solutions. The model is further extended to a two-dimensional (2-D) axisymmetric diaphragm clamped at the periphery. Interrelationship between bridge-pad gap, residual membrane stress, critical voltage, and pull-in central deflection is derived such that new design criteria can be derived for micro-/nano-electromechanical devices. Implications for nano-structures are also discussed.     

Measurement of potential distribution function on object surface by using an electron microscope in the mirror operation mode

The quantitative theory of image contrast in an electron microscope in the mirror operation mode is given in this paper. This theory permits us to calculate the potential distribution on the object surface from the current density distribution on the microscope screen. The potential distribution results in image formation on the screen. Local electric fields existing on the object surface lead to a perturbation of electron trajectories above the object and to a redistribution of the current density on the screen, causing image contrast. Using the quantitative correlation between these fields and the function of current density distribution on the screen, it is possible to calculate the magnitude of these microfields as well. As illustration, a measured potential distribution on an object surface with spiral structures of adsorbates was analysed. These structures are formed during reaction of CO oxidation on Pt(110). The value of the measured contact potential difference comprised a few hundredths of volt.     

Determination of the distribution of consolidants and interpretation of mercury porosimetry data in a sandstone porous network using LSCM

Knowing the 3D distribution of a consolidant within the porous network of a rock is essential for understanding the porosity quantitative data obtained by mercury porosimetry and for observing the effect of consolidants on pore interconnection. In this work, we show for the first time that the distribution of consolidant in the porous network can be determined using laser scanner confocal microscopy (LSCM). Results indicate that consolidants are concentrated in pore throats of less than 40 microm in diameter, affecting both the porous interconnection and the circulation of fluids. LSCM allowed demonstration of the fact that the increase in microporosity detected by mercury porosimetry is due to the development of fissures within the consolidants. No consolidant that produces this kind of fissure can be used in the consolidation of building stones, since it would increase microporosity and, in consequence, vulnerability to weathering agents.