Determination by volumetric methods

PCT and Kinetic Curves Determination by Volumetric Method in a Sieverts-Type Apparatus... 

Dymova et al. investigated the decomposition of KAIH4 up to 750 °C by D SC and X-ray diffraction methods [153,154]. The amount of hydrogen released was determined by volumetric methods. Three endothermic thermal effects associated with the release of hydrogen are assigned to the following decomposition steps (Eqs. (5.28)-(5.30)) ... 

The consumption of oxidant is most generally determined by volumetric methods—periodate by titration with arsenite, and both oxidants by iodime-try. Spectrophotometric methods are also frequently used for determining periodate and lead tetraacetate, and are especially useful for microoxidations or highly dilute reaction mixtures. Spectrophotometric determination of the extent of conversion of the violet dye tris[2,4,6-tris(2-pyridyl)-l,3,5-triazino]iron(II) into its colorless ferric state reportedly provides a means of quantitating nanomole amounts of unreacted periodate, and it has been coupled... 

Other gases are absorbed and determined by volumetric methods only in special cases. A solution of palladium(II) chloride or colloidal palladium and picric acid absorbs hydrogen, a solution of potassium dichromate is used for sulfur dioxide, and a solution of cadmium acetate or alkaline solution of hydrogen peroxide for hydrogen sulfide. 

This value, Cl/literf, is the quantity determined by volumetric methods and is defined in the same manner as chlorinity except that the sample unit is 1000 ml of sea water at a stated temperature rather than 1 kg of sea water weighed in vacuo. 

Analytical Methods. Loss on Ignition. Wet density, dry mass density, organic content, and carbonate content were determined by the method of Dean (33). Volumetric samples (1.0 cm 3) were dried overnight at 100 °C and ignited at 550 and 1000 °C for 1 h. Mass measurements were made on the wet sample and after each heating on an electronic analytical balance. 

The aim of an indigo sensor is to keep the leuco-indigo concentration in the solution at a constant value. In the past, different methods were developed for detection of the indigo and sodium dithionite concentration, but up to now with limited success. The sodium dithionite concentration can be determined by volumetric titration with iodine2 22 or with K3[Fe(CN)6]23. The endpoint detection of these titrations can be done visually22,24"25 or... 

To determine PCT curve by volumetric method at first we have to know mass of analyzed powder (hydride or pure metal). The typical mass of powder used in volumetric method is in a range 50-500 mg and depends on VR (reactor volume with volume of connecting pipes, valves, and transducer). After the mass measurement, the powder is loaded into specimen holder and then it is placed in the Sieverts apparatus reactor. To prevent any oxidation and for safety reason the system must be purged a few times by argon and then evacuated. However, one must be careful how much powder is appropriate for the absorption/desorption volume of a Sieverts-type apparatus. 

The volumetric flow rate determined by this method is usually within 10 percent of the true volumetric flow rate. 

Most adsorption data were collected by volumetric method until microbalance of high sensitivity appeared few years ago. It can hardly say which method is superior to the other, and both methods need the value of the skeleton volume of sample adsorbent. This volume has to be subtracted from the whole volume of the sample container to obtain the volume of void space, which is used for the calculation of the amount adsorbed. The skeleton volume of sample adsorbent was directly used in the calculation of buoyancy correction in gravimetric method. This volume was usually determined by helium assuming the amount of helium adsorbed was negligible. If, however, helium adsorption cannot be omitted, error would yield in the skeleton volume and, finally, in the calculated amount adsorbed. However, the effect of helium adsorption would be much less for volumetric method if the skeleton volume is considerably less than the volume of void space, but the volume of void space cannot affect buoyancy correction. In this respect, helium adsorption would result in less consequence on volumetric method especially when the skeleton volume was determined at room temperature and pressures less than IS MPa. The skeleton volume (or density) was taken for a parameter in modeling process in some gravimetric measurements. However, the true value of skeleton volume (or density) can hardly be more reliable basing on a fitted parameter than on a measured value. Therefore, one method of measurement cannot expel the other up to now, and the consequence of helium adsorption in the measured amount adsorbed should be estimated appropriately. 

In order to determine ephedrine in aerosols, Lawless et al. expired the aerosol through a piece of stainless-steel tubing into a 10 ml volumetric flask containing acetone. The volumetric flask was brought to volume and an aliquot injected for the gas chromatographic analysis on a 1.15 % SE-30 packed column at 171°C. Over 99.5 % of the amount of ephedrine present in the aerosol could be determined by this method. 

Volumetrically tellurium may be determined by several methods (1) Tellurous acid is oxidized to telluric by permanganate either in acid solution 3 or alkaline solution.4 (2) Tellurous acid in hydrochloric acid solution is reduced by an excess of standard stannous chloride, according to the reaction TeCl< + 2 SnCU — Te + 2 SnCL. The excess stannous chloride is determined iodometrically.5 (3) Telluric acid may be reduced to tellurous by the use of potassium bromide in sulfuric acid solution, thus H2TeO< + 2 HBr = H2TeO + H20 + Br2. The bromine is distilled into a solution of potassium iodide, the liberated iodine being determined by standard thiosulfate.6... 

Tracers (40, 41) are used primarily to estimate volumetric sweep and to locate steam channels. The tracer should not react with the reservoir. The four main categories of tracers are radioisotopes (e.g., tritium and krypton), which are used in steam floods salts (e.g., sodium bromide and sodium nitrate) fluorescent dyes (e.g., uranian) and water-soluble alcohols (e.g., methanol, ethanol, and 2-propanol). The surfactant itself may be used as a tracer. Its concentration at production wells may be determined by using methods such as liquid chromatography, colorimetry, and titration. 

While total organic matter is defined as arbitrary physical fractions (dissolved, particulate, and volatile), the recommended methods for their measurement are similar. An outline of the methods used for analysis of organic carbon in sea-water samples is shown in Fig. 7. Most of these methods are based on oxidation of organic matter to CO2 which is determined by volumetric, gravimetric, conductometric, titrimetric, or coulometric methods... 

The present research is devoted to the study of the physical-ehemical properties of natural zeolites from Armenia. The adsorption of H2, O2, Ar, N2, CO2, SO2 0n natural mordenite from Shirak deposit as well as the adsorption of Ar, N2, SO2 and Xe on Shirak mordenite treated by hydrochloric acid have been studied by volumetric method. The kinetics of O2, Ar and N2 adsorption on natural mordenite have been studied. The isosteric heats of adsorption for H2, O2, Ar, N2, CH4, CO2, SO2, Xe have been measured by chromatographic method. The portion of quadropole interaction has been determined. 

Formic acid is produced from a 1,2,3-triol grouping. As this acid is stable toward periodate, it is readily determined by volumetric or potentiometric titration of the reaction mixture, by highly sensitive spectrophotometric methods, or manometrically. Lead tetraacetate slowly oxidizes formic acid to carbon dioxide, which may complicate the stoichiometry of the glycol-cleavage... 

But instead of speculating, it would be most valuable to study the surface and bonding character of adsorbates as a function of time with tihe variety of surface analytical tools available. Moreover, the rate and amount of adsorption (and desorption) may be studied by volumetric methods or microbalance techniques. Bonding information may also be obtained from the heats of adsorption and desorption. Infrared multiple reflection spectroscopy should reveal the characteristic bending modes of adsorbed molecules and allow a quantitative determination of the surface coverage as a function of prior surface treatments and of annealing. 

Total organic carbon It refers to the amount of organically bound carbon present in sewage. Its measurement is based on the oxidation of organic carbon to CO2, which can be subsequently determined by several methods (e.g., volumetric, gravimetric, conductimetric, coulometric). 

The overall reaction is characterized by product analyses and coulombic efficiency determinations. Carbon dioxide, which is the primary product in most organic reactions at noble-metal anodes, can be removed from acidic solutions in the anode compartment of the electrolytic cell by passing an inert gas through the cell, and then reacting quantitatively, e.g., with Ba(OH)2 or Ascarite. Carbon dioxide is not as easily determined in alkaline electrolyte, which must be analyzed, e.g., by volumetric methods or chromatography. Nonvolatile products from the oxidation are determined by analysis of the electrolyte, e.g., by gas chromatography, preferably with a flame ionization detector, or mass spectroscopy. Organic products can be extracted from the electrolyte... 

Very often, determination of the fission gas fraction released during operation from the fuel pellet to the rod free volume is required. To this end, the fuel rod is punctured inside a hot cell using a special experimental device the gas inventory of the rod, mainly consisting of helium, is then collected in an evacuated volume and measured by volumetric methods. Analysis of the individual gas composition is usually performed by mass spectrometry. 

The only practical chemical methods for the determination of any of the individual rare earths from each other and, especially, adjacent lanthanides are based on the oxidation of cerium(III) to cerium(lV) and the determination of Ce(IV) by gravimetric or volumetric methods as discussed in previous sections. Fractional crystallization methods can be used to separate the rare earths into subgroups, but clean separations of adjacent rare earths are not feasible. As mentioned previously, Eu, Sm, and Yb can be reduced to the plus two oxidation state, but only Eu(II) can really be satisfactorily determined by chemical methods. 

The chemisorption of carbon monoxide is an established method for determining the surface area of dispersal metals, particularly in supported catalysts. The average area occupied by each molecule depends on whether attachment is on one or two sites, a state that can vary from metal to metal and with surface coverage [85]. The quantity of chemisorbed gases is commonly measured by volumetric methods with apparatus similar to that used for static BET gas adsorption measurements. 

The structure of a polymeric network is ultimately determined by the method of synthesis. The monomer and crosslinker concentrations, the initiator type and concentrations, the relative reactivities of the monomers, the specific solvent and reaction temperature are all significant factors. Commercially, the rate of the polymerization reaction is also of importance, since It directly affects the volumetric efficiency of the production equipment. Fortunately, many of the important structural parameters are determined by the polymerization kinetics and by the various stoichiometries of the reaction. 

The amount of uranium In a sample may be determined by standard methods of analysis gravimetric, volumetric, colorimetric, spectrophotometrlc, etc. ... 

Automated equipment generally determines the adsorption isotherm by volumetric methods. This consists of adding a known amount of adsorbate gas to the sample cell. The amount of gas adsorbed at the equilibrium pressure is the difference between the amount of gas incorporated and the gas needed to fill the space around the solid, defined as the dead space of the cell. Once the equilibrium is reached, more adsorbate gas is added into the cell and the isotherm is constructed by incorporating increasing amounts of the adsorbate. 

The preferred method of determining water in glycerol is by the Kad Fischer volumetric method (18). Water can also be determined by a special quantitative distillation in which the distilled water is absorbed by anhydrous magnesium perchlorate (19). Other tests such as ash, alkalinity or acidity, sodium chloride, and total organic residue are included in AOCS methods (13,16,18). 

Nickel also is deterrnined by a volumetric method employing ethylenediaminetetraacetic acid as a titrant. Inductively coupled plasma (ICP) is preferred to determine very low nickel values (see Trace AND RESIDUE ANALYSIS). The classical gravimetric method employing dimethylglyoxime to precipitate nickel as a red complex is used as a precise analytical technique (122). A colorimetric method employing dimethylglyoxime also is available. The classical method of electro deposition is a commonly employed technique to separate nickel in the presence of other metals, notably copper (qv). It is also used to estabhsh caUbration criteria for the spectrophotometric methods. X-ray diffraction often is used to identify nickel in crystalline form. 

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