DNA and RNA sensor

The development of DNA sensors attracts recentresearch attention directed at gene analysis, such asdetection of genetic disorders, tissue matching andforensic applications[1,2]. In general, sensors based on the principle differ-ent from that of the tr…     

Progress in oscillographic chronopotentiometry

This review summarizes recent advances in DNA sensor. Major areas of DNA sensor covered in this review include immobilization methods of DNA, general techniques of DNA detection and application of nanoparticles in DNA sensor.     

A Study of Multi-order Semidifferential Oscillographic Chronopotentiometry

ASemiintegralelectroanalysishasbeenimprovedanddevelopedsinceOldhamlwhofirstintroduceditinl972,andiswidelyaPpliedtoseveralkindsofpolarographicanalysis"'suchaslinearsweepvoltammetry,cyclicvoltammetryandanodicstrippingvoltanunetry.Anewfieldinelectroanalysis,neopolarographicmethod,isformed.Thismethodhasmanyadvantages,forexample,highsensitivity,goodresolvingpower,simPlicityofinstrUmentstructureandlowcost.Itissuitableforthestudyoffastanalysisandfastelectrodereaction.Determinationcanbecarriedouteve…     

示波分析研究的新进展

综述了近年来示波分析的新进展,内容包括：计算机和化学计量学在示波分析中的应用以及多阶半微分和高低频交流示波计时电位法,银电极交流示波计时电位法等示波分析新方法,引文献75篇。     

小示波图及其应用

提出了小示波图的概念, 建立了基于小示波图的示波计时电位法. 在以汞电极为工作电极的示波计时电位法中, 采用端点去极剂切割经典示波计时电位图后形成的小示波计时电位图(简称为小示波图). 根据切割经典示波图所用的端点试剂不同, 将小示波图分为三种类型. 推导了小示波图的理论公式, 提出了小示波图的调节方法, 并将其用于几种物质的定量测定. 研究表明, 利用小示波图不仅能使在经典示波图端点附近不易准确测定的物质得以测定, 还可以在宽广的电位窗口内灵活、稳定、灵敏、高选择性地进行示波测定. 因此, 小示波图示波测定法是对经典示波测定法的一个重要的补充和发展.     

示波分析在中国的发展：Ⅴ.示波测定

综述了半个多世纪以来，我国在示波测定方面的研究和应用概况。     

程控电流示波计时电位法

使用计算机产生极化电流具有纯度高，稳定性好和波形形状种类多等优点。研究了极化电流的频率，波形和相角对示波图的影响。对Ｃｄ＾２＋的测定的线性范围为２×１０＾－５～２×１０＾－４ｍｏｌ／Ｌ，相关系数为０．９９７，该方法可且希望用于分析测试和动力学方面的研究。     

示波分析在中国的发展：Ⅲ.示波滴定在药物分析中的应用

示波滴定法具有终点直观，操作简便，仪器简单，价格低廉，分析快速，易于推广等优点。将示波滴定法应用于药物分析可以发迹药物分析方法落后的现状。     

3.5次微分循环示波计时电位法的研究

将半积分半微分技术应用于循环示波计时电位曲线的处理,可大大抑制充电电流的影响,提高示波测定的灵敏度和分辨率.据此,本文提出了3.5次微分循环示波计时电位法,研究了该方法的特点并将其用于HAc-NaoH-铜铁试剂(HCup)体系中铅示波特性的研究和微量铅的测定.     

The Investigation of Oscillographic Chronopotentiometry at Silver Disk Electrode and Its Mechanism

A.C.oscillopolarographyintroducedbyHeyrovskyinl94lhasbeendevelopedintoanewfieldofelectroanalyticalchemistry-osciIIographicanaIysis'.Astothedevelopmentofelectrode,thechangefromthedroppingmercuryeIectrode(DME)tothesolidelectrode(thehangingmercurydropelectrodeormercuryfilmelectrode)makesoscillographicanalysisarealpracticalvaIue2.Hencedevelopinganewtypeofelectrodeisimportantfortheprogressofoscillographicanalysis.Thepresentpaperdescribestheinvestigationofoscillographicchrono-potentiometryatsilv…     

喹诺酮类药物的示波测定

喹诺酮类药物属于人工合成抗生素 ,至今已开发或正在开发的约 5 0多种 ,成为抗感染药物中最活跃的研究领域之一 ,是一类有巨大潜力的新型抗菌药 .喹诺酮类药物的测定 ,大多采用高效液相色谱法 [1～ 3 ] .但高效液相色谱仪的价格昂贵 ,测定对样品的处理要求较高 ,应用受到限制 .示波分析法具有仪器简单、操作简便、选择性高等优点 ,用此法测定吡哌酸、诺氟沙星含量已有报道 [4～ 6] .本文进一步研究了依诺沙星 (ENX)、环丙沙星(CPLX)、氧氟沙星 (OFLX)、氟罗沙星 (FLRX)和司帕沙星 (SPLX)等 5种喹诺酮类药物的示波测定条件及方法 .S…     

反弹传播神经网络用于痕量铬的示波计时电位法测定

首次将反弹传播算法神经网络用于铜箔钝化液中痕量铬的示波计时电位法测定。探讨了网络层数、层结点数和结点转移函数等网络参数对预测结果的影响。实验结果表明 :Cr 浓度在 4.0× 10 -7～ 1.3× 10 -6mol/L范围内与示波计时电位曲线上的切口深度呈线性关系 ,检测下限可达 8× 10 -8mol/L ;与标准BP神经网络的训练和预测结果相比较 ,反弹传播神经网络用于示波测定时不仅具有较高的预测精度 ,而且大大提高了网络训练的收敛速度     

Determination of chloride by stripping chronopotentiometry with silver-film electrode

The experimental parameters of cathodic stripping chronopotentiometry of chloride at a silver-film electrode are investigated and optimized. The chloride preconcentration is achieved in the form of silver chloride by a controlled potential oxidation of the working electrode under vigorous stirring. Cathodic stripping of the deposit is obtained by the constant current, under the condition of diffusive mass transfer. Deaeration of the solution is not necessary. A detection limit of 35 μ dm⁻³ (10⁻⁶ mol dm⁻³) is obtained at a deposition time of 180 s, with a reproducibility of 6.7 % (expressed as relative standard deviation, RSD).     

微分倒数示波计时电位法的研究—定量测试及滴定分析

首次利用微分倒数示波图定量测试微量金属离子并滴定分析药物，结果满意。     

3.5次微分循环示波计时电位法测定铋的研究

本文将３。５次微分循环示波计时电位法应用于铋的示波特性的研究和合成样品中微量铋的测定。铋在０．１ｍｏｌ／Ｌ ＮａＯＨ支持电解质中，于示波图阴极支上产生一灵敏切口，灵敏度为２×１０＾－７ｍｏｌ／Ｌ，线性范围为４×１０＾－７－２×１０＾－６ｍｏｌ／Ｌ。     

Oscillographic Chronopotentiometry with High and Low Frequency Current

Thekey.bywhichoscillographictitrationmaywellbeinvolvedintooscillographicanalysis,istoenhancethereproducibility,sensitivityandresolutionofoscillogram.Whenitcomestothereproducibility,itcanbeimprovedbyimprovingtheexperimentalcircuit.varyingstabilityofpolarizedcurrent,anddevelopingastaticoscillographicanalysisintoadynamicoscillographicanalysis"=.Inrespectofresolving,wemayresorttosomesignalprocessingtechniques,suchaswavelettransformandFouriertransform3-5.Sofarassensitivityisconcerned,therearemanywa…     

慢扫速示波计时电位法的研究

慢扫速示波计时电位法的研究朱俊杰，郑建斌，胡娟，高鸿（南京大学化学系，南京，２１０００８）关键词慢扫速示波计时电位法，切口，灵敏度在经典示波计时电位法中接受信号的装置是示波器，这是由于使用交流电的频率较高（一般大于１０Ｈｚ）［１］，只有通过示波器才能...     

Measurement of total calcium by flash chronopotentiometry at polymer membrane ion-selective electrodes

Ionophore-based ion-selective electrodes are widely used for potentiometric electrolyte measurements, in which case they are known to detect the free ion activity. Total ion concentrations cannot be directly assessed by this methodology if the ion is predominantly present in a complexed form. We present here the direct measurement of total calcium using a calcium ion-selective electrode interrogated in a flash chronopotentiometric transduction mode. A high magnitude of cathodic current pulse is applied across a calcium ion-selective membrane containing the ionophore ETH 5234 but void of ion-exchanger to prevent spontaneous extraction. This induces a defined flux of calcium ions from the sample side to the membrane and results in the release of labile bound calcium and a concomitant depletion at the membrane surface at a critical current or time. This is observed as an inflection point on the potential-time curve and the square root of the transition time is linearly related to the total concentration in the sample. It is shown that the responses to solutions of labile calcium complexes of nitrilotriacetic acid (NTA) are in a good agreement with that of the same concentration of calcium chloride in saline solution with this protocol. Initial applications are aimed towards assaying extracellular calcium. Calcium binding to albumin is shown to be inconsequential with sample dilutions typical for clinical assays. Calcium calibration curves in real and artificial dilute serum are finally shown to correspond to that of calcium chloride, suggesting that the methodology is indeed capable of detecting total calcium under these conditions. The present membrane materials allow detection of up to over 0.5 mM total calcium in serum, currently requiring such samples to be diluted about 5-fold. The slopes of the square root of time-concentration dependence for the calibrations of free calcium in a background of NaCl and total serum calcium were found to be 3.857 and 3.717 s^1/2 mM⁻¹, respectively, deviating by just 3.6%. The lower detection limit (3× SD) was calculated as 12 μM.     

Measurements of trace concentrations of mercury in sea water by stripping chronopotentiometry with gold disk electrode: influence of copper

A stripping chronopotentiometric method, using a rotating gold disk electrode for mercury measurements in sea water is described. Compared with a same method using a stationary gold film electrode, this method has a eight times higher sensitivity and a detection limit of 5 ng l⁻¹ after 10 min deposition time. Moreover, the time needed for gold plating is eliminated. Compared with other electrochemical methods capable of measuring mercury at low concentrations, the present method is more simplified with no degassing step and no need to use a medium-exchange procedure before the stripping step. These characteristics render the method easily practicable on board oceanographic vessels for ‘in situ’ measurements.     

Determination of dissolved sulphides in waste water samples by flow-through stripping chronopotentiometry with a macroporous mercury-film electrode

Sulphides in water samples were determined by stripping chronopotentiometry in a computer controlled flow system with a flow-through electrochemical cell. The working electrode was a porous glassy carbon electrode coated with Nafion and mercury. The sample was diluted with 0.1 mol L⁻¹ NaOH and analysed. Sulphides in the sample were collected in the porous electrode as mercury sulphide and then stripped by a current of −500 μA. The limit of detection was found to be 1.6 μg L⁻¹ and 0.5 μg L⁻¹ for 1 mL and 5 mL of preconcentrated sample, respectively. The linear range for 1 mL sample was found to be 5-400 μg L⁻¹. The repeatability and reproducibility was found to be 2.6% and 4.8%, respectively. The method was applied to analyses of waste water samples from a tannery.