Applicability to analytical problems

P. J. Barker, H. J. Stronks 1990, (Application of the low resolution pulsed NMR MINISPEC to analytical problems in the food and agriculture industries), in NMR Applications in Biopolymers, eds. 

Electroanalytical chemists and others are concerned not only with the application of new and classical techniques to analytical problems, but also with the fundamental theoretical principles upon which these techniques are based. Electroanalytical techniques are proving useful in such diverse fields as electro-organic synthesis, fuel cell studies, and radical ion formation, as well as with such problems as the kinetics and mechanisms of electrode reactions, and the effects of electrode surface phenomena, adsorption, and the electrical double layer on electrode reactions. 

Atomic absorption spectroscopy is the term used when the radiation absorbed by atoms is measured. The application of AAS to analytical problems was considerably delayed because of the apparent need for very high resolution to make quantitative measurements. In 1953, Walsh brilliantly overcame this obstacle by the use of a line source, an idea pursued independently by Alkemade, his work being published in 1955. 

Inevitably developments in all fields of analytical chemistry find their applications to the problems of the chemist in the field of petroleum. Thus ion exchange, microwave techniques, nuclear resonance, radioactive isotopes, activation analysis, high frequency vibrations, and other developments of fundamental research should find applications in the field of petroleum analysis. 

Electron Microscopy 22) C.]. Burton, AralChem 21, 36-40(1949) (Application of electron microscopy to analytical problems includes 159 references) 23) R.W.G. Wyckoff, " Electron Microscopy, Technique and Applications , fnterscience, NY(1949)... 

Mass spectrometry can also be used for the investigation of various analytical and structural problems with thiophenes. The method can be extremely sensitive, allowing the detection and identification of trace amounts. Techniques involving ionization (photoelectron spectroscopy, a technique also encompassed in PIPECO techniques) can be useful for the solution of structural problems. Applications to the problem of tautomerism in thiophenes may be mentioned (75ACS(B)647, 75ACS(B)652>. 

It is obvious from the FTIR and NMR analyses of these extracts that in order to positively identify organosulfur structures we need an analytical technique that is sulfur selective. That is, a technique that responds to sulfur uniquely. One such technique, applicable to the problem in hand, is GLC-FID/FPD where the flame photometric detector is set in the sulfur selective mode. 

Applications of Square-wave Polarography to Analytical Problems from... 

The efforts with respect to the latter objective have broadened the scope and applicability range of MS ionic and highly polar analytes, even biomacromolecnles, are now amenable to MS analysis. The "odd couple" [1] is now moving borders and opening new application areas. LC-MS has become a technique that has found wide application, that can give solutions to analytical problems, and that will certainly continue to grow in the years to come. 

Although the sensitivity obtained with RIS is impressive, analytical calibration in specialized reservoirs presents some practical problems. In the laser ablation/RIS scheme, these limitations are particularly pronounced because of the nature of the sampling process. Relative calibration techniques, commonly used by analytical chemists, imply the availability of accurate standards at the appropriate concentration 9), The current state of knowledge about the dynamics of the ablation process did not permit absolute calibration with any confidence. The coupling of highly sensitive and selective RIS with mass spectrometry should result in more generally useful applications to analytical chemistry10). 

Figure 1. Applicability of immunochemistry to analytical problems. The background indicates all compounds for which analysis is needed while the respective circles indicate the subset of compounds for which gas chromatography (GC), high performance liquid chromatography (HPLC), and immunoassay (IA) are most applicable. For those compounds which can be readily analyzed by a variety of methods, the decision of which assay to use should be made based on the analytical questions to be answered.

Application of the Raman Microprobe to Analytical Problems of Microelectronics... 

The use of mathematical and statistical modeling methods to relate chemical data sets to the state of the chemical system is referred to as chemometrics. A key figure in the development of chemometrics and its application to industrial problems has been B.R. Kowalski [18, 147, 319] who led the Center for Process Analytical Chemistry (CPAC) that was established in 1984. To aid qualitative and quantitative analysis of chemical data, Eigenvector Technologies Inc., a developer of independent commercial software, has provided a number of software solutions, primarily as a Matlab Toolbox [328]. 

The earliest applications of NMR to analytical problems in the food industry employed CW techniques. Commercial pulsed NMR instruments were introduced at a later stage, but pulsed NMR is now the more widely used of the two methods. Practical aspects of low-resolution pulsed NMR techniques have been reviewed21,286 and the manufacturers (Bruker, Oxford) application notes also provide valuable information on specific procedures. 

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