Multiple chemical sensitivity characteristics

TABLE 18-2. Six common characteristics of multiple chemical sensitivities... 

Schottenfeld RS Workers with multiple chemical sensitivities a psychiatric approach to diagnosis and treatment. Occup Med 2 739-753, 1987 Scott AE Clinical characteristics of taste and smell disorders. Ear Nose Throat J 68 297-315, 1989... 

Environmental exposme to organic solvents is supposed to be one cause of multiple chemical sensitivity which characterizes nemopsychological disorders. Organic solvents from paints seem to play a role. The relevant exposxue characteristics (dose, time, possible dose-response relationship) are also discussed. ... 

A good, well-chosen biomarker of exposure should have several qualities. One is it should be specific for the exposure of interest some metabolites are common to multiple chemical substances and may not be a suitably specific biomarker. Even a small quantity of the biomarker should be easily detectable therefore, high sensitivity is important. Also, the biomarker should be associated with exposure. Ideally, biomarkers should provide good predictive value to a specific health status and have reference values in the population if possible. Low overall analysis expense is another desirable characteristic of biomarker analysis for use in biomonitoring. The availability of suitable economical reference standards, as well as low-cost sample preparation, is an important consideration for extensive studies. This also implies that the analytical measurement procedure for the biomarker should have high throughput capability. Finally, measurements by non-invasive techniques are desirable. Urine-based biomarkers, either parent compounds or metabolites, are widely used in biomarker research today. Blood drawing is... 

A further characteristic of chemical reaction engineering is its facility in refining concepts. It is a derived characteristic, stemming from the mathematical component of the subject, but it has been typical of its development since the distinction between stability and sensitivity was first drawn (34). There have been lapses, alas, as in the case of an expository paper (52) which, to judge by the demand for offprints, proved quite useful, but which rated a very low Watkins number (53), for its title was "On the stability criteria of chemical reaction engineering" while its burden was as much the multiplicity criteria as the stability conditions. But there has been a steady incorporation of precisely defined concepts as for example in the burgeoning study of... 

The current research focus within the sensor development field seems to be concentrated on miniaturization while incorporating multiple quantitative analytical capabilities. Other high-demand characteristics are shorter response time, minimal hardware requirements, multiple analyte and media capabilities, and improved sensitivity, selectivity, and specificity (Zemel 1990). Advancements and improvements for both biological and chemical threat agent sensors will have numerous other benefits to diverse applications, such as quality and process control, biomedical analysis, medical diagnostics, fragrance analysis, environmental pollution monitoring, and control forensics. 

The ICP has proliferated as a method of converting chemical compounds into their elemental constituents which subsequently emit light of characteristic wavelengths. Accordingly, ICP has been used extensively as an emission source for optical detection systems in order to perform elemental analysis. Since each element can emit hundreds of optical lines, the use of ICP/AES for multiple element analysis, or for the detection of elements in unknown or concentrated matrices, can suffer from interferences due to spectral overlap. By contrast, ICP-MS provides inherently simpler spectral Information. An example of such a spectrum is demonstrated in Figure 2 showing a typical ICP-MS scan for a 10 ug ml"l solution of mixed transition metals. The demonstrated sensitivity here is 10 to 10 counts s l per ug m1"l and, coupled with the nearly universal ionization efficiency of the ICP ion source, provides typical detection limits in a narrow range between 0.1 to 10 ng.ml" for most elements. In fact over 90% of the elements in the periodic table are accessible for such analytical determinations. 

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