Indirect determinations

In the previous section we used four examples to illustrate the different ways that mass can serve as an analytical signal. These examples also illustrate the four gravimetric methods of analysis. When the signal is the mass of a precipitate, we call the method precipitation gravimetry. The indirect determination of by precipi-... 

Directions are provided for the determination of chloride in samples using CZE. The buffer solution includes pyromellitic acid which allows the indirect determination of chloride by monitoring absorbance at 250 nm. 

The material charge of continuous mills called the holdup cannot be set directly but is indirectly determined by operating conditions. There is a maximum throughput rate that depends on the shape of the mill, the flow characteristics of the feed, the speed of the mill, and the type of feed and discharge arrangement. Above this rate the holdup increases unstably. 

INDIRECT DETERMINATION OF ASCORBIC ACID BY ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY... 

The recent development and comparative application of modern separation techniques with regard to determination of alkylphosphonic acids and lewisite derivatives have been demonstrated. This report highlights advantages and shortcomings of GC equipped with mass spectrometry detector and HPLC as well as CE with UV-Vis detector. The comparison was made from the sampling point of view and separation/detection ability. The derivatization procedure for GC of main degradation products of nerve agents to determine in water samples was applied. Direct determination of lewisite derivatives by HPLC-UV was shown. Also optimization of indirect determination of alkylphosphonic acids in CE-UV was developed. Finally, the new instrumental development and future trends will be discussed. 

The adherend metallurgy also indirectly determines the degree of smut buildup because the rate of smut formation is proportional to the etch rate [54J. For instance, the etch rate of A606 is four times greater than that of A514, due to differences in grain size, etc. As a result, a different etch treatment is required for each. In general, the roles of alloy and heat-treatment differences have not... 

The procedure involved in the determination of these anions is virtually that discussed in Section 10.58 for the indirect determination of silver. The anion to be determined is precipitated as the silver salt the precipitate is collected and dissolved in a solution of potassium tetracyanonickelate(II) in the presence of an ammonia/ammonium chloride buffer. Nickel ions are liberated and titrated with standard EDTA solution using murexide as indicator ... 

In many cases, the values of A n and k2i may be directly or indirectly determined. We shall say no more about this relationship here, other than to indicate that it proves to be generally applicable, and is sufficiently accepted that the Marcus-Hush equation is now used to establish when an outer-sphere pathway is operative. In the context of this chapter, the involvement of the Kn term is interesting for it relates to the relative stabilization of various oxidation states by particular ligand sets. The factors which stabilize or destabilize particular oxidation states continue to play their roles in determining the value of Kn, and hence the rate of the electron transfer reaction. 

At that point, it should also be kept in mind that the values of bond lengths and angles are not directly accessible from experiments but are indirectly determined so as to reproduce the rotational constants which are themselves deduced from microwave experiments. Thus, comparison are always subject to some controversy since there is no biunivoque correspondence between the geometry and the rotational parameters. 

K., Steele, K. P. Indirect determination of octanol-water partition coeffidents by microemulsion electrokinetic chromatography. J. Chromatogr. A 1996, 744,141-146. 

The ultimate goal of multivariate calibration is the indirect determination of a property of interest (y) by measuring predictor variables (X) only. Therefore, an adequate description of the calibration data is not sufficient the model should be generalizable to future observations. The optimum extent to which this is possible has to be assessed carefully when the calibration model chosen is too simple (underfitting) systematic errors are introduced, when it is too complex (oveifitting) large random errors may result (c/. Section 10.3.4). 

Bayon, M. M., Rodriguez Garcia, A., Garcia Alonso, J. I., and Sanz-Medel, A., Indirect determination of trace amounts of fluoride in natural waters by ion chromatography a comparison of on-line post-column fluorimetry and ICP-MS detectors, Analyst, 124, 27, 1999. 

Serum ferritin—the best indirect determinant of body iron stores. It is commonly decreased in patients with iron-deficiency anemia. 

Nehring, U. P., Maier, H. G., Indirect determination of degree of roast in coffee, Lebensm.-Unters. Forsch. 195(1), 39, 1992. (CA117 190397q)... 

Scheme 6. Synthesis of dendrimer 22 a and its TMSI mediated conversion (dedendronization) to 22b. 22b is needed to indirectly determine the molecular weight of 22a...

Specular reflection IR spectroscopy has been used by Cole and coworkers to study the orientation and structure in PET films [36,37]. It has allowed characterizing directly very highly absorbing bands in thick samples, in particular the carbonyl band that can show saturation in transmission spectra for thickness as low as 2 pm. The orientation of different conformers could be determined independently. Specular reflection is normally limited to uniaxial samples because the near-normal incident light does not allow measuring Ay. However, it was shown that the orientation parameter along the ND can be indirectly determined for PET by using the ratio of specifically selected bands [38]. This approach was applied to the study of biaxially oriented PET bottles [39]. 

The radiation strength of a single electron is determined by elementary quantities that need not be considered in materials science. These quantities and the characteristics of the detector are automatically considered if the primary beam intensity is directly measured or indirectly determined by means of a secondary standard. 

This establishes the natural relation between the modulus and the minimum nonzero eigenvalue of the force constant matrix. The precise form of this relationship, i.e., the values of the constants, depends upon the geometry of the body, both through the boundary conditions on the continuum and through the structure of the force constant matrix, which indirectly determines m... 

Substances easily oxidized and indirectly determined (ascorbic, acid, carboxylic acids, amines, etc.)... 

The POCL reaction has been used for trace determinations of hydrogen peroxide, most commonly in environmental and clinical analysis [26-52], The latter applications often include various enzyme systems [34-52], where a number of substrates can be indirectly determined by measuring the hydrogen peroxide that is produced as a by-product in the enzymatic reaction. 

The luminol reaction has also been used for the CL determination of organic substances such as penicillins [32] and tartrate ion [30] in pharmaceutical preparations by their inhibitory effect on the luminol-iodine and luminol-periodate-manganese(II)-TEA system, respectively. As can be seen from Table 1, the results were quite satisfactory. In the indirect determination of penicillins by their inhibitory effect on the luminol-iodine system, the stopped-flow technique improves the accuracy and precision of the analytical information obtained, and also the sample throughput [32], Thus, in only 2-3 s one can obtain the whole CL signal-versus-time profile and calculate the three measured parameters formation and... 

Most of the relevant substances within household appliances cannot be measured directly with any kind of sensor. Several applications have been described that can indirectly determine one or several parameters. Sensors which rely on changes of weight, turbidity or conductivity have already implemented, while direct determination of substances with chemical or biochemical sensors is still problematic because of insufficient stability and reproducibility. 

Blago, R.B. 1989. Indirect determination of free cyanide by atomic absorption spectroscopy. Atom. Spectros. 10 74-76. 

An interesting application of atomic absorption spectroscopy is the indirect determination of nonmetals. Christian and Feldman 191 have described the various indirect methods that can be used. Methods have been described for the determination of several nonmetals in biological samples. 

Several investigators have described the indirect determination of orthophosphate by extraction of the phosphomolybdic acid complex and the measuring the molybdenum extracted. Zaugg and Knox 2921 first applied this technique to the determination of phosphate in urine. A protein-free filtrate was formed and the complex was extracted into 2-octanol. More recently, Devoto 293) determined 0 to 25 pg of phosphate in 50 ml of urine by extracting the complex from acidified urine into isobutyl acetate. 

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