Titration techniques

A controlled potential coulomctric titration has also been developed for the determination of technetium. Pertcchnetatc was titrated in an acetate buffered (pH 4.7) aqueous solution of sodium tripolyphosphate (NasP-.Oio) at a potential of-0.70 V vs SCE. Under these conditions TcOj was found to be quantitatively reduced to Tc(lII). In the range of 0.5-5 mg of titrated TCO4, the relative error of the method was about 1 % and the relative standard deviation 0.5%. The ions Fc(lll), Mo(Vf), Ru(fV), U(V1). V(IV), F , and NOs interfere strongly. Technetium can be removed from these ions by distillation from cone, sulphuric acid solution [102[. 

Several titration methods were studied for determining Tc(IV) or Tc(VII) in the concentration range of 10 -10 M. Tc(IV) was titrated volumctrically with Ce(TV) using potcntiomctric, biampcrometric, and bipotentiomctric detection of the equivalence point. The most precise results were obtained by coulomctric titration of TcOj 

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Total basicity is measured by standard acid—base titration techniques. The activity divided by the total basicity should be greater than 90%. If it is not, then the Grignard reagent should be checked for unreacted alkyl or aryl haUde, homo-coupled product, hydrolysis products, and oxidation products. 

Only slightly less accurate ( 0.3—0.5%) and more versatile in scale are other titration techniques. Plutonium maybe oxidized in aqueous solution to PuO " 2 using AgO, and then reduced to Pu" " by a known excess of Fe", which is back-titrated with Ce" ". Pu" " may be titrated complexometricaHy with EDTA and a colorimetric indicator such as Arsenazo(I), even in the presence of a large excess of UO " 2- Solution spectrophotometry (Figs. 4 and 5) can be utilized if the plutonium oxidation state is known or controlled. The spectrophotometric method is very sensitive if a colored complex such as Arsenazo(III) is used. Analytically usehil absorption maxima and molar absorption coefficients ( s) are given in Table 10. Laser photoacoustic spectroscopy has been developed for both elemental analysis and speciation (oxidation state) at concentrations of lO " — 10 M (118). Chemical extraction can also be used to enhance this technique. 

A subsequent investigation using spectrophotometric and titration techniques indicated that the reaction order in carboxylic acid was approximately three and that first-order rate coefficients were, in fact, independent of the initial concentration of mercury compound606. The reaction mechanism was proposed as... 

Initial surfactant concentration was 0.50% wt in pH 8.5 solution. 50 g of test solution was placed over 100.0 g crushed Berea sandstone. The sample bottle was sealed and shaken continuously for 24 h at 75°C. The mixed indicator titration technique was used to determine active surfactant concentration before and after exposure of the test solution to crushed Berea sandstone. AS HAS, alkene.hydroxyalkanemonosulfonate ratio. D.I. water, deionized water. ND, not determined. 

Alternative variations of the isothermal titration technique utilize CO adsorption followed by reaction with gaseous 02. Experiment has shown that similar Nc values are obtained.1,19... 

Example 36 Four batches. A, B, C, and D, of an amino acid hydrochloride were investigated four different titration techniques were applied to every sample ... 

A one-way (simple) ANOVA with six replicates can be conducted by either regarding each titration technique or each batch as a group, and looking for differences between groups. 

Apparatus and Procedure. The apparatus and procedure were identical to those outlined in ref. Surface composition measurements were based on an O2-CO titration technique described by Miura and Gonzalez (5-6). The ratio of surface metal/02/CO was 1/1/T on Ru-sllica, 1/0.5/1.75 on Rh-sllica, 1/0.5/2.0 on Pt-silica and 1/0.5/1.6 on Ir-silica. These titration ratios were found to be independent of surface composition. Surface compositions determined by the O2-CO titration method have been verified using a variety of experimental techniques (2,5-6). 

The experimental approaches used to characterize ion-pair partitioning are cyclic voltammetry and potentiometric titration. Cyclic voltammetry is overall more powerful, but requires special instrumentation which is not commercially available as a ready-to-use set-up. For this reason the potentiometric titration technique has been more widely used. 

In a wider sense the subject of voltammetric titration would include the polarographic mode as a type of amperometric titration however, we have already treated this in Section 3.3.1.3, because we prefer to use the term voltammetric titration in the strict sense, i.e., for faradaic non-polarographic titration techniques, a survey of which is given in Table 3.3. 

Fig. 3.71 offers an instructive possibility for considering the voltammetric titration techniques mentioned in Table 3.3, and we shall do so in the sequence given there. 

In certain types of multiprotic molecules it is possible that chemically different species of the same stoichiometric composition are formed [142,230-244]. The pH-metric titration technique cannot distinguish between such tautomeric species. In such cases the determined pKa is a composite constant, a macroconstant. The... 

The measurement of absorbance of light by a dyestuff-anionic surfactant complex, which has been extracted into an organic solvent is a key feature of many methods, and Sodergren has successfully used segmented flow colorimetry for an automated version of this procedure (2 ). An alternative is the two phase titration technique, pioneered by Herring (3) which uses dimidium... 

The theta (0) conditions for the homopolymers and the random copolymers were determined in binary mixtures of CCl and CyHw at 25°. The cloud-point titration technique of Elias (5) as moaified by Cornet and van Ballegooijen (6) was employed. The volume fraction of non-solvent at the cloud-point was plotted against the polymer concentration on a semilogarithmic basis and extrapolation to C2 = 1 made by least squares analysis of the straight line plot. Use of concentration rather than polymer volume fraction, as is required theoretically (6, 7 ), produces little error of the extrapolated value since the polymers have densities close to unity. 

The purpose of this article is to review the results of transient low pressure studies of carbon monoxide oxidation over transition metal substrates. Particular emphasis is given to the use of in-situ electron spectroscopy, flash desorption, modulated beam and titration techniques. The strengths and weaknesses of these will be assessed with regard to kinetic insight and quantification. An attempt will be made to identify questions that are ripe for investigation. Although not limited to it, the presentation emphasizes our own work. A very recent review of the carbon monoxide oxidation reaction C l) will be useful to readers who are interested in a more comprehensive view. 

Photoemission of adsorbed xenon, abbreviated as PAX, is a site-selective titration technique, in which the UPS spectrum of physisorbed Xe reveals the nature of the Xe adsorption site [52, 53]. Since we are dealing with a weakly physisorbing atom, these experiments have to be done at cryogenic temperatures on the order of 50-60 K. We first explain the theory behind the PAX method and then illustrate the technique with an example. 

Nichols, J. W. and Deamer, D. W. (1980). Net proton hydroxyl permeability of large unilamellar liposomes measured by an acid-base titration technique, Proc. Natl Acad. Sci. USA, 77, 2038-2042. 

Mettler produce two automatic titrimeters the DL 40 GP memotitrator and the lower-cost DL 20 compact titrator. Features available on the DL 40GP include absolute and relative end-point titrations, equivalence point titrations, back-titration techniques, multi-method applications, dual titration, pH stating, automatic learn titrations, automatic determination of standard deviation and means, series titrations, correction to printer, acid balance analogue output for recorder and correction to the laboratory... 

The Kjeldahl digestion-titration technique [44] discussed in section 12.5.1.1 for the determination of total nitrogen in soils has been applied to the determination of total nitrogen in sediments. 

Theory Nitrazepam is a weakly basic compound and hence, it may be titrated conveniently by means of a non-aqueous titration technique and determining the end-point potentiometrically. 

The p-t-butylcalix[4]arenediquinone-bis(methylether) [56], which had previously been synthesized by Gutsche and co-workers, was used as a model compound in these studies. The receptors [54] and [55] have been shown by nmr titration techniques to form 1 1 solution state complexes with group 1 and 2 metal, ammonium and alkylammonium guest species. 

Table 18 Stability constant data determined by nmr titration techniques. 

The effect of fluoridation with hydrofluoric acid on the. surface acidity of catalytic alumina was also studied by Ballou e< al. (340), About 1 % of fluoride was taken up by the catalyst. The surface acidity was estimated using a titration technique developed by Benesi (341a). After addition of varying amounts of butylamine in benzene solution, the color changes... 

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