Quantitative reliability

Qualitative analysis methods should have well-grounded and generally adopted quantitative reliability estimations. At first the problem was formulated by N.P. Komar in 1955. Its actuality increased when test methods and identification software systems (ISS) entered the market. Metrological aspects evolution for qualitative analysis is possible only within the scope of the uncertainty theory. To estimate the result reliability while detecting a substance X it is necessary to calculate both constituents of uncertainty the probability of misidentifications and the probability of unrevealing for an actual X. There are two mutual complementary approaches to evaluate uncertainties in qualitative analysis, just as in quantitative analysis ... 

The detection and quantification of cyanobacterial toxins quoted in the above examples required methods which have been undergoing rapid development in recent years, and as the need for greater understanding of the properties and occurrence of the toxins continues to grow, these are continuing to be developed. This has resulted in methods of cyanobacterial toxin detection which are more sensitive, quantitative, reliable, specific and humane. Many of these methods are presented and discussed in the proceedings of a recent conference. 

In this paper we examined quantum aspects of special classical configurations of two-electron atoms. In the doubly excited regime, we found quantum states of helium that are localized along ID periodic orbits of the classical system. A comparison of the decay rates of such states obtained in one, two and three dimensional ab initio calculations allows us to conclude that the dimension of the accessible configuration space does matter for the quantitative description of the autoionization process of doubly excited Rydberg states of helium. Whilst ID models can lead to dramatically false predictions for the decay rates, the planar model allows for a quantitatively reliable reproduction of the exact life times. 

The advantages of CC in ultra trace analysis are shown to be unmistakable. The quantitative reliability of the method was demonstrated by the extension of a calibration graph for phenol to two decades of concentration more when compared with conventional chromatography. A considerable improvement of the signal-to-noise ratio can be achieved in a relatively short time. The method offers excellent prospects for ultra trace analysis in cases where preconcentration of the solute fails. 

To compile quantitatively reliable information, we need a source of experimental measurements. One way to determine the nature of inter-molecular forces between biopolymer molecules in a solvent medium is to measure the so-called osmotic second virial coefficient A2. Expressed in molar (biopolymer) terms, the quantity A2 can be related to the two-body potential of mean force W(r) by the following equation (Vrij, 1976 de Kruif, 1999 Prausnitz, 2003 de Kruif and Tuinier, 2005) ... 

Hg flux and watershed area, the relative importance of direct deposition and catchment contributions can be assessed. Such interpretations assume that lake sediments are stratigraphically and quantitatively reliable archives of Hg inputs to aquatic systems. 

Fyfe et al. (384) obtained quantitatively reliable 29Si NMR spectra of silica gel and high-surface area glass beads and of derivatized surfaces without resorting to cross-polarization. Spin-lattice relaxation times of these systems are of the order of 10-30 sec and spectra of adequate quality may be obtained at high fields. 

The stable free radicals in coal can adversely affect the 13C signal intensity. However, the quantitative reliability of the method can be greatly improved by prior treatment of coal with chemicals such as samarium(II) iodide (Stock et al., 1988) to selectively reduce the organic free radicals. Thus, this potential error that has influenced the quantitative aspects of the method can be reduced by the use of a novel pretreatment technique as well as an appropriate standard for measurement of chemical shifts. 

The issue of quantitative reliability of solid-state 13C NMR methods has been investigated by a number of researchers (Mao et al., 2000, 2002a Hatcher et al.,... 

Detailing the right-hand sides of these equations with changing parameters of the environment will determine the qualitative and quantitative reliability of the model. In particular, the model can be simplified by approximating the average value of W0 ... 

Although compound recognition in the ECD methods is based on retention time, superb selectivity of this detector makes compound identification and quantitation reliable in interference-free matrices. The ECD s supreme sensitivity to halogens and oxygen is also its greatest weakness. Example 4.10 illustrates this point. 

The first point to be stressed in any account of metal ion bonding is the great success of simple ionic calculations of bond energies for the IA and IIA metal halides. (At the same time we should note that no covalent model has ever achieved quantitative reliability.) Thus Fig. 2 shows that... 

Computational quantum chemistry and solid state physics have reached the stage where quantitatively reliable predictions on the interaction of small and moderate sized molecules with transition metal clusters or surfaces are now possible. Computation therefore be-... 

Unfortunately, quantitatively reliable quantum chemical calculations of nucleation rates for atmospherically relevant systems would require the application of both high-level electronic structure methods and complicated anharmonic thermochemical analysis to large cluster structures. Such computations are therefore computationally too expensive for currently available computer systems, and will likely remain so for the foreseeable future. Instead, a synthesis of different approaches will probably be necessary. In the future, successful nucleation studies are likely to contain combinations of the best features of both classical (Monte Carlo and molecular dynamics) and quantum chemical methods, with the ultimate objective being a chemically accurate, complete configurational sampling. 

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