微分倒数示波计时电位滴定

倒数示波计时电位滴定~[1]是最近提出的一种电滴定方法,它把(dE/dt)-E曲线上的切口转变为(dE/dt)~(-1)-E曲线上的峰,从而大大抑制了充电电流,提高了滴定分析的灵敏度.本文报道了微分倒数示波计时电位滴定,即对(dE/dt)~(-1)-E曲线进行一次或二次微分处理,利用示波图上去极剂峰的出现与消失指示终点,使滴定终点更易观察.     

Méthode pratique de dosage ampèrométrique du manganèse

A practical method is described .for thu determination of manganese by ampcrometnc titration.The Mn⁺² ion is oxidized quantitatively into Mn⁺³ (complex formation) by titration with permanganate in approximately neutral pyrophosphate solution. We have found that the end point of this Litration appears both very clearly and accurately by using a most simple electiometric device. A. platinum and a silver wire dipping in the solution are connected directly to a pointer galvanometer. The so revealed current remains very low during the titration and suddenly increases at the equivalence point.Tins titration can be effected quickly. The growing instability of the pointer usefully warns of approaching end point. There is practically no interference from foreign ions and theercfore the method can be applied widely and easily.     

基于质子条件式的终点误差精确式

容量分析中,滴定终点的误差决定了该分析方法的可靠性。根据质子条件式,可推导出终点误差的精确式。该表达式用滴定开始前而不是终点时物质的浓度进行计算;用滴定终点时的p H进行计算,不需要计算化学计量点时的p H;所得出的精确式具有通用性,能有效降低学习与记忆的难度,提高计算结果的准确度。     

Four points function fitted and first derivative procedure for determining the end points in potentiometric titration curves: statistical analysis and method comparison.

A new method that belongs to the differential category for determining the end points from potentiometric titration curves is presented. It uses a preprocess to find first derivative values by fitting four data points in and around the region of inflection to a non-linear function, and then locate the end point, usually as a maximum or minimum, using an inverse parabolic interpolation procedure that has an analytical solution. The behavior and accuracy of the sigmoid and cumulative non-linear functions used are investigated against three factors. A statistical evaluation of the new method using linear least-squares method validation and multifactor data analysis are covered. The new method is generally applied to symmetrical and unsymmetrical potentiometric titration curves, and the end point is calculated using numerical procedures only. It outperforms the "parent" regular differential method in almost all factors levels and gives accurate results comparable to the true or estimated true end points. Calculated end points from selected experimental titration curves compatible with the equivalence point category of methods, such as Gran or Fortuin, are also compared with the new method.     

示波库仑滴定

示波滴定的理论和实际应用近几年来发展较快,但过去的工作多限于常量分析。库仑滴定可获得较高的准确度和灵敏度,但常常因缺乏简便、灵敏的终点指示方法而使其应用范围受到限制。若将这两种方法结合起来,则既可弥补库仑滴定法的不足使滴定终点变得简单直观,又可使示波技术用于痕量分析。本文报道两铂电极示波电位滴定终点指示技     

硼酰化钴中硼的快速测定

硼酰化钴中硼的测定采用EDTA作为钴的络合掩蔽剂,消除了钴对测定硼的影响。同时改用溴甲酚绿-甲基红-酚酞三元混合指示剂作为测定硼的指示剂,使滴定终点灵敏、准确。建立了一种测定硼酰化钴中硼含量的简便、快速的分析方法。     

非水滴定法测定酰胺缩醛

对非水滴定酰胺缩醛的溶剂、滴定剂和指示剂进行了选择试验，用ＨＣｌ甲醇标准液进行滴定，通过电位滴定曲线或甲基橙指示剂可以准确的确定滴定终点，方法简便，结果准确。     

示波极谱-银量法的研究

示波极谱－银量法是以示波图形的突变来确定终点。其终点直观,不受溶液的颜色、沉淀、赋形剂的影响。可将重量分析变为滴定分析,具有准、快、简、省的特点,有广泛的应用前景。     

交流示波极谱滴定法测定吡哌酸

本文介绍用交流示波极谱滴定法测定吡哌酸的含量。在ＨＣｌ－ＮａＡｃ缓冲溶液中，加入过量的Ｎａ－ＴＰＢ与吡哌酸作用生成沉淀，过滤后用亚铊标准溶液定滤液中过量的ＴＰＢ，由交流示波极谱图上ＴＰＢ的切口消失指示终点。本法操作简便，终点直观，应用于原料药样品的测定，并与药典法相对照，结果基本吻合。     

示波非水电位滴定法及其在药物分析上的应用

本文介绍一种非水电位滴定指示终点的新方法,即用阴极射线示波器取代常用的测量电压的装置。将样品溶于含适量醋酐的冰醋酸中,加入适量的醋酸汞,用微铂球电极作指示电极,甘汞电极作参比电极,它们直接与阴极射线示波器的y轴和接地相连,两电极间无任何外加电压,滴定终点时两电极间电位差(△E)产生瞬时突变,示波器荧光屏上荧光点的跳移指示滴定终点。用本法测定了11种有机碱药物,和法定方法作了比较,结果无显著性差异。