Potential and Limitations

the ATR technique yields much information which may be one of its greatest limitations. An ATR spectrum of a working heterogeneous catalytic system simultaneously provides information about dissolved and adsorbed reactants and products, adsorbed intermediates, byproducts, spectators, and the catalyst itself. The technique is unspecific in the sense that a signal cannot a priori be assigned to dissolved or adsorbed species or the catalyst itself. Thus, analysis of the data requires more effort and specific techniques, such as the ones discussed in detail below. In the following we illustrate the points raised above by some examples. 

This example illustrates another important issue of ATR spectroscopy carried out during heterogeneous catalytic reactions. Concentrations of products determined by ATR can be different from those observed by other techniques such as GC analysis (49,75. There are primarily two reasons for the differences  

A strength of ATR spectroscopy in heterogeneous catalysis is the opportunity it affords for detection of adsorbed species while the catalyst is working. Detection is 

Identification of an adsorbate may be facilitated by simple adsorption of a precursor that resembles it, or just the adsorbate itself, such as CO (e.g., panel (c). Fig. 21). Adsorbed reaction intermediates on Pd/Al2O3 for 2-propanol oxidation were identified by using time-resolved ATR spectroscopy and quantum chemical calculations 45), as described in detail below. Reaction intermediates are usually 

The latter system was also modeled on the basis of the formalism outlined above (Eqs. (11)—(22)), which provided insight into the origin of the observed changes (49). 

---

Chromatographic techniques, particularly gas phase chromatography, are used throughout all areas of the petroleum industry research centers, quality control laboratories and refining units. The applications covered are very diverse and include gas composition, search and analysis of contaminants, monitoring production units, feed and product analysis. We will show but a few examples in this section to give the reader an idea of the potential, and limits, of chromatographic techniques. 

Henderson R 1995 The potential and limitations of neutrons, electrons and x-rays for atomic resolution microscopy of unstained biological molecules Q. Rev. Biophys. 28 171-93... 

The advantages of LA are now well-known - no sample preparation is needed, conducting and non-conducting samples of arbitrary structure can be analyzed directly, spatial resolution up to a few microns can be obtained, high vacuum conditions are not required, rapid simultaneous multi-element analysis is possible, and it is possible to obtain complete analytical information with a single laser pulse. A brief overview of the potential and limitations of LA will be given in this chapter. 

J. Staniewski and J. A. Rijks, Potential and limitations of differently designed pro-grammed-temperature injector liners for lar ge volume sample intr oduction in capillary GC, 7. High Resolut. Chromatogr. 16 182-187 (1993). 

In vivo reproducible results can only be achieved if the liposome-drug or -antigen combinations are thoroughly characterized upon preparation in terms of their physical and chemical properties and, besides, if the stability during storage is ensured. In this chapter both the pharmaceutical (preparation, characterization, and stability) aspects and the therapeutic potentials and limitations of drug and antigen delivery with liposomes will be discussed. 

Recently we reviewed the literature (Peeters et al., 1987) dealing with the potential and limitations of immunoliposomes in the treatment... 

White R.J. (1982) Microbiological models as screening tools for anticancer agents potentials and limitations. Annu Rev Microbiol, 36,415-433. 

The occurrence in some plants of secondary metabolites characterized by an 0-heterocyclic structure and exhibiting antimicrobial properties is a well-known phenomenon [2,8-10]. Among them, catechins and proanthocyanidins are two classes of compounds exhibiting antimicrobial properties towards both prokaryotic and eukaryotic microorganisms. Yet, despite the large number of studies published so far, the real potentialities and limitations given by the use of this class of molecules as antiviral or antimicrobial (antibacterial, antimycotic, antiprotozoal) agents have not been critically evaluated. The present chapter represents an overview of the re-... 

Giang NTH (2011) Potentials and limitations of energy recovery from municipal solid waste (MSW) in Vietnam. PhD Thesis, Institute of Waste Management and Contaminated Site Treatment, University of Technology, Dresden... 

Steiner S et al. Expression profiling in toxicology - potentials and limitations. Toxicol Lett 2000 112-113 467 171. 

The objective of the WFD is to implement an optimal ecological integrity in European water bodies. Overall, this is a very ambitious objective that needs to be fulfilled by 2015, and in the meantime the development of methodologies have evidenced both the potentials and limitations of the so-called ecological status approximation. 

Solid experience in S5mthetic chemistry deep understanding of its potentials and limitations... 

More work is necessary to discover more fiilly the potential and limitations of high pH work. 

Michalke, B. (2005). Capillary electrophoresis-inductively coupled plasma-mass spectrometry a report on technical principles and problem solutions, potential, and limitations of this technology as well as on examples of application. Electrophoresis 26, 1584—1597. 

Ciambelli, P Corbo, P Migliardini, F. Potentialities and limitations of lean de-NOx catalysts in reducing automotive exhaust emissions, Catal. Today, 2000, Volume 59, Issues 3-4. 279-286... 

A more selective inhibition of NFkB can be achieved by transfecting cells with DNA coding for the natural inhibitor IkBo or a mutant IkB protein that lacks 36 N-terminal amino acids, and consequently becomes proteolysis resistant. In this way expression of adhesion molecules and monocyte adhesion and transmigration can be inhibited [87,88], The potentials and limitations of these latter types of therapy are however not fully understood as yet. Different transfection systems (adenoviral, retroviral, non-viral) are available for gene delivery purposes, all with their own potentials and restrictions. 

In contrast to isolated hepatocytes, liver slices retain the cellular architecture of the Uver without prior digestion with collagenase. This makes a systematic comparison of the data relating to transport of free drugs as well as drug targeting moieties from isolated hepatocytes and liver slices, an attractive model for studying the potential and limitations of the liver slice model in this area of research. 

The present volume is in several respects unique. It provides a map of the body from the viewpoint of drug targeting/drug delivery. Potentials and limitations of targeting strategies... 

Kolbe, B. and Gmehling, J., Thermodynamic properties of ethanol + water, II. Potentials and limits of G models. Fluid Phase Equilibria, 23 (1985) 227-242. 

Shrank W, Avorn J. Educating patients about their medications the potential and limitations of written drug information. Health Aff 2007 26 731-40. 

M. Rudin and A. Sauter, In vivo phosphorus-31 NMR potential and limitations. in In-Vivo Magnetic Resonance Spectroscopy III In-Vivo MR Spectroscopy Potential and Limitations, M. Rudin (ed.), Springer-Verlag, Berlin, 1992,161-188. 

Weighing the potential and limitations of the technique as elaborated in this article—and furthermore on the basis of the fact that the technique and instrumentation are easily accessible, we predict that ATR-IR spectroscopy will become a powerful and widely used tool for the investigation of heterogeneous catalytic reactions occurring in the presence of liquid-phase reactants. 

---