Titrations determination

E. SCHOLZ, Karl Fischer Titration Determination of Water, Springer Verlag, Berlin, 1984, 150 pp. 

The first titration determines the amount of EDTA used by the iron, and the second, the amount of EDTA used by the chromium. 

This is one source of acid rain, a serious environmental problem. The sulfur dioxide content of an air sample can be determined. A sample of air is bubbled through an aqueous solution of hydrogen peroxide to convert all of the SO2 to H2 SO4. H2 O2 + SO2 H2 SO4 Titration of the resulting solution completes the analysis (both H atoms of H2 SO4 are titrated). In one such case, the analysis of 1.55 X 10 Lof Los Angeles air gave a solution that required 5.70 mL of 5.96 X 10 M NaOH to complete the titration. Determine the number of grams of SO2 present in the air sample. 

Analytical determinations with the fluoride ion-selective electrode These are based either on direct potentiometry of fluorides [37, 84, 85, 88, 430] or on titration determinations of either fluorides or of other ions and also on titrations with fluoride ions as indicator. The advantages of potentiometry with an ISE over other analytical methods for determining fluorides were pointed out by Crosby etai [67], Further comparison studies [42, 56, 191, 433] came to the same conclusions, confirmed also by a study of 16 methods [365]. Fluoride ions are titrated either with La (for concentrations greater than 1 mM) or Th (in the concentration range 0.2-1 mM F ) [13, 102, 103, 113,233, 234]. Titration with fluoride ions can be used for the determination of Al with formation of the AIF4 complex up to nanomolar concentrations, especially in ethanol-water mixtures [25] (see also [267,384]). Precipitation titrations can also be used to determine La, Th and UOJ [241, 384] as well as Li in... 

The question of the differences (Table IV) between log P s determined using standard conditions, 0.1 IJ HCl and octanol, and titration determined values must be addressed. At this point they cannot be es lained. It remains to be seen which method more nearly represents the biolipid concentration of ionized species under physiological conditions. 

You can measure the equilibria in this system by effectively titrating the acidic hydrogens on these waters, and the equilibrium measurements show—I don t want to get involved in the details of the measurements—but they show that starting with approximately a 0.01 M ion concentration, gives comparable quantities of what must be the sum of these two isomers. This is what titration determines. Their combined concentrations must be roughly equal to the trichloro species and the concentration of the diaquo species will be very small. 

Iodine, colorimetric determination of amylase using, 689-692 Iodine value, lipid composition canola oil, 474 (table) oil quality indices, 467-469, 475-477 lodometric titration, determination of peroxide value, 518-519 Ionization techniques, in mass... 

To analyze sulfide (S2 ) in an aqueous sample, 150 mL of sample was made ammoniacal before argentometric titration. The sample required 10.45 mL of 0.0125 M AgN03 solution in the titration. Determine the concentration of the sulfide in the sample. 

These complexes are weak enough that, in the complexometric titration determination using EDTA, they break and are included in the total calcium hardness reported. Thus, the total calcium hardness is composed of the legitimate cation, Ca, plus the complex ions as shown in the previous equations. This total calcium hardness must be corrected by the concentrations of the complexes in order to determine the correct activities of the calcium ions. Let the total concentration of the calcium species as determined by the EDTA titration be [Car]. Thus, the concentration of the calcium ion [Ca a )] is... 

The water content was determined by Karl Fischer titration. Determined by H NMR on the crude reaction mixture. 

The titration-determined molecular weights of the individual samples were used to calculate the amount of benzophenone required to completely derivatize the amine functionalities. A 10 mol % excess of benzophenone was used to ensure complete derivatization. The reaction was done in bulk at 80 °C by heating the siloxane oligomer and benzophenone for 24 h in the presence of 3-A molecular sieves. GPC analysis was then carried out at 30 °C with a Waters 590 GPC apparatus equipped with ultrastyragel columns with particle sizes of 500, 10, 10", and 10" A. A Waters 490 programmable wavelength detector set at 218 nm was used with THE (tetrahydro-fiiran) as the solvent. 

Chemical tests, electrometric titration determinations, and ab.sorption spectrum studies gave clues to its composition. These were substantiated by the synthesis of vitamin B6 (1938 and 1939). Two additional chemical forms, pyridoxal (an aldehyde) and pyridoxamine (a primary amine), have been isolated from natural sources. These three compounds are interrelated metabolically and functionally. The intcrcon-version between the different forms is shown below. 

Karl Fischer Titration Moisture content of reference standards is commonly and accurately determined by Karl Fischer (KF) titration. KF titration determines total water content, including both the free water and water of hydration trapped in the crystal structure. Coulometric KF-titration is the most sensitive application of the method and is normally used for the small amounts of water found in reference standards. A volumetric technique is available for samples containing large amounts of water. Interference is a relatively common problem in KF titration and thus, due caution must be exercised in the interpretation of KF results. Reagents have been designed to cope with interfering functional groups.48-50... 

Schultz, T.H. 1965. Determination of the degree of esterification of pectin. Determination of the ester methoxyl content of pectin by saponification and titration. Determination of the anhydrouronic acid content by decarboxylation and titration of the liberated carbon dioxide, in Methods in Carbohydrate Chemistry 5, New York Academic Press, pp. 189-194. 

Acidity and alkalinity titrations determine the total capacity of natural waters to consume strong bases or acids as measured to specified pH values defined by the endpoints of titrations. Of more interest for many purposes is the ability of a water or water-rock system to resist pH change when mixed with a more acid or alkaline water or rock. This system property is called its buffer capacity. Buffer capacity is important in aqueous/environmental studies for reasons that include ... 

The yield is 80-90%, determined as follows. A 5 or 10 mL aliquot of the solution is withdrawn by means of a pipet connected to a rubber suction bulb, and hydrolyzed by adding to distilled water (10 mL). This is titrated with standard acid to determine the total alkali, using phenolphthalein as indicator. A second 5 or 10 mL aliquot is withdrawn and run into a solution of anhydrous ether (10 mL) containing benzyl chloride (1 mL). The mixture is allowed to stand for 1 min after the addition and is then hydrolyzed with water (10 mL) and titrated with standard acid. Care must be taken not to overstep the end point since the aqueous layer becomes decolorized before the ether layer. To overcome this the mixture should be shaken vigorously near the end point. The second titration determines the alkali present in the form of compounds other than n-butyllithium. The difference between the two titration values represents the concentration of n-butyllithium. 

Figure 29 Biamperometric titration determination of isoniazide in tablets.

No practical apphcations are given in this area to cover food analysis, although the reader is referred to the References section, "additional recent references" portion, for some suggestions. The paper by Kalbus and Lieu represents, for example, a laboratory experiment in the coulometric titration determination of the iodine number of fats and oils. For a practical experiment the following determination of arsenic by coulometric titration is suggested. It is of interest since it presents to alternatives in the final estimation procedure. 

H.V. Malmstadt, E.C. Gohrbandt, Automatic spectrophotometric titrations. Determination of milligram quantities of thorium, Anal. Chem. 26 (1954) 442. 

Only one bottle will be needed for DOf and DOf if a DO electrode is used. If replicate determinations are carried out, it is customary to carry out a single determination on the initial DO bottle and have replicates for the final DO determinations, which are subject to greater variation i.e., for Winkler titration determination of DO, three bottles are prepared, one used immediately for DOf and the other two incubated and used for DOf determination. 

TABLE 4. Capacities of functionalized ROMP monoliths. determined by titration, determined by elemental analysis (percent of nitrogen). by weight. 

Frycdk, P, Schug, K.A. (2007) On-line dynamic titration determination of dissociation constants for noncovalent complexes using Gaussian concentration profiles by electrospray ionization mass spectrometry. Anal. Chem., 79, 5407-5413. 

Problem 4.4 A sample (2.0 g) of polyether polyol prepolymer (M = 2048) dissolved in chlorohydrocar-bon solvent was treated with excess succinic anhydride to convert each hydroxyl group in the polyol to a carboxyl group by formation of succinic half-ester. A sample (1.0 g) of this treated polymer recovered from the solution by precipitation (in excess of ethanol) required 12.8 mL of N/10 KOH for carboxyl titration. Determine the hydroxyl functionality of the polyol. 

Determined by UV-vis titrations. Determined by H NMR titrations. Mixed with 0.5% H2O. 

Spectrophotometric titrations of proteins Side chain of many amino acids contain ionizable groups which are available for titration. Determination of pK values for proton dissociation from these ionizable groups often provides a good indication about the position of these amino acids in the protein. This can best be understood by taking into account the example provided below.. ... 

A piece of steel (an alloy of iron and carbon) of mass 0.200 g reacts with dilute sulfuric acid. The resulting solution requires 34.00cm of 0.0200 mol dm potassium manganate(vii) in acidic solution in a titration. Determine the percentage by mass of iron in the steel. 

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