As titrant

Finding the End Point Potentiometrically Another method for locating the end point of a redox titration is to use an appropriate electrode to monitor the change in electrochemical potential as titrant is added to a solution of analyte. The end point can then be found from a visual inspection of the titration curve. The simplest experimental design (Figure 9.38) consists of a Pt indicator electrode whose potential is governed by the analyte s or titrant s redox half-reaction, and a reference electrode that has a fixed potential. A further discussion of potentiometry is found in Chapter 11. 

Aqueous solutions of hexamethylenetetramine (HMTA) can be used as titrant for acids concentration determination [1], Aqueous solutions HMTA are extensively used in complexonometry as a buffer. 

DETERMINATION OF CALCIOM IN THE PRESENCE OF MAGNESIUM USING EGTA AS TITRANT 10.61... 

DETERMINATION OF CALCIUM IN THE PRESENCE OF BARIUM USING CDTA AS TITRANT... 

Place the prepared copper acetate solution in the beaker and add 10 mL of 20 per cent potassium iodide solution. Set the stirrer in motion and add distilled water, if necessary, until the platinum plate electrode is fully immersed. Use a saturated calomel reference electrode, and carry out the normal potentiometric titration procedure using a standard sodium thiosulphate solution as titrant. 

Sodium dodecyl sulfate is the universal analytical standard for the determination of anionic and cationic active matter. It is used to determine the analytical concentration factor of the cationic surfactant in the titration of anionic active matter and as titrant to determine the cationic active matter. 

A manual titrimetric method using methyl orange as indicator and sodium tetraphenylboron as titrant has been described [273]. Dodecyl sulfate at concentrations of approximately 10"5 M have been analyzed by a visual two-phase titration in the presence of dichloroethane and tetrabromophenolphthalein ethyl ester [274]. 

As we saw in Section L, titration involves the addition of a solution, called the titrant, from a buret to a flask containing the sample, called the analyte. For example, if an environmental chemist is monitoring acid mine drainage and needs to know the concentration of acid in the water, a sample of the effluent from the mine would be the analyte and a solution of base of known concentration would be the titrant. At the stoichiometric point, the amount of OH " (or 11,0 ) added as titrant is equal to the amount of H30+ (or OH-) initially present in the analyte. The success of the technique depends on our ability to detect this point. We use the techniques in this chapter to identify the roles of different species in determining the pH and to select the appropriate indicator for a titration. 

Electrodes of the first kind have only limited application to titration in non-aqueous media a well-known example is the use of a silver electrode in the determination of sulphides and/or mercaptans in petroleum products by titration in methanol-benzene (1 1) with methanolic silver nitrate as titrant. As an indicator electrode of the second kind the antimony pH electrode (or antimony/antimony trioxide electrode) may be mentioned its standard potential value depends on proton solvation in the titration medium chosen cf., the equilibrium reaction on p. 46). 

It also suggests that an excess of either anionic or cationic surfactant causes a change in droplet size and an increase in light scattering. Therefore, it should be possible to mimic the two branches of the titration curve emanating from the equivalence point by starting with pure brine (35 cm3) and chloroform (10 cm3) and using either hyamine or SDBS as titrants. Experiments undertaken to examine this hypothesis are described below. 

Papovic et al. [14] used a conductometric method for the determination of primaquine phosphate. This method is recommended with perchloric acid, silicotungstic acid, and sodium hydroxide as titrants. Conductometric curves obtained with... 

The purity of the product can be determined 3 6 by titration in glacial acetic acid, using perchloric acid (in glacial acetic acid) as titrant and methyl violet (0.2 g. of methyl violet in 100 ml. of chlorobenzene) as visual indicator (the first appearance of blue color is taken as the end point). 

SACHEM Inc. of Cleburne, Texas, manufactures various concentrations of tetramethylammo-nium hydroxide (TMAH) solutions to meet customer specifications. To ensure consistent performance, electronic industry requires very narrow concentration specifications for the solutions. In SACHEM s quality control laboratory, standardized acids such as HC1 or H2S04 are used as titrants for the TMAH solutions to check their concentrations. The performance of the assay titration is controlled by daily analysis of internal reference standards (IRSs). If the IRS results are within controlled limits, then the assay results of a product can be reported. If not, the results cannot be reported until the root cause is uncovered and eliminated. Safety glasses and gloves are worn while performing this work in the laboratory. 

Oximes and hydroxamic acids are frequently used as titrants, for masking, as metal-lochromic or chromogenic indicators as well as for spectrophotometric determinations. 

Poten dome trie detn of NGu) (Acet solvent with Et4- or Bu4NOH as titrant)] 12) G.F. Atknin et al, ZavodskLab 32(7), 802—4(1966)... 

The lyate ion of DMSO (Cl l SOCI l2 ) is called dimsyl ion. Its alkali metal salts have been used as titrant in DMSO [25 a]. 

The fluoride ion selective electrode is the most popular means of fluoride ion determination after sample destruction by any method but it does have limitations. It can be used either directly to measure the fluoride potential6 or as an end-point detector in a potentiometric titration with a lanthanum(l II) reagent as titrant.4,7 Problems can be experienced with potential drift in direct potentiometry, especially at low fluoride ion concentrations. Titration methods often yield sluggish end points unless water miscible solvents are used to decrease solubilities and increase potentia 1 breaks and sulfate and phosphate can interfere. End-point determination can be facilitated by using a computerized Gran plotting procedure.4... 

Many reagents used as titrants, such as HC1, are not available as primary standards. Instead, we prepare titrant with approximately the desired concentration and use it to titrate a primary standard. By this procedure, called standardization, we determine the concentration of titrant. We then say that the titrant is a standard solution. The validity of the analytical result ultimately depends on knowing the composition of a primary standard. 

The titration curve is a graph showing how the concentration of one of the reactants varies as titrant is added. Because concentration varies over many orders of magnitude, it is most useful to plot the p function ... 

In a spectrophotometric titration, absorbance of light is monitored as titrant is added. For many reactions, there is an abrupt change in absorbance when the equivalence point is reached. The Fajans titration is based on the adsorption of a charged indicator onto the charged surface of the precipitate after the equivalence point. The Volhard titration, used to measure Ag+, is based on the reaction of Fe3+ with SCN- after the precipitation of AgSCN is complete. 

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