Specific Compounds

Table 9.9 Selected examples of compound specific instraments

Hansen KJ, LA Clemen, ME Ellefson, HO Johnson (2001) Compound-specific quantitative characterization of organic fluorochemicals in biological matrices. Environ Sci Technol 35 766-770. 

Jarman WM, A Hilkert, CE Bacon, JW Collister, K Ballschmiter, RW Risebrough (1998) Compound-specific carbon isotopic analysis of Arochlors, Clophens, Kanechlors, and Phenoclors. Environ Sci Technol 32 833-836. 

This technique detects substances qualitatively and quantitatively. The chromatogram retention time is compound-specific, and peak-height indicates the concentration of pollutant in the air. Detection systems include flame ionization, thermal conductivity and electron capture. Traditionally gas chromatography is a laboratory analysis but portable versions are now available for field work. Table 9.4 lists conditions for one such portable device. 

Aliphatic fluorodenitration has also been applied to mononitro compounds, specifically to an a-nitroepoxide Thus, l,2-anhydro-3 4 5,6-di-O isopropyli dene-1-C-nitro D mannitol and labeled potassium bifluonde give 2-deoxy-2-fluo-ro-3,4 5,6-di-O-isopropylidene aldehydo D glucose [J03, 104] (equation 30) 

Stott, A.W., Davies, E., Evershed, R.E. and Tuross, N. 1997 Monitoring the routing of dietary and biosynthesized lipids through compound-specific stable isotope (delta C) measurements at natural abundance. Naturwissenschcften 84(2) 82-86. 

If one of the above colors is used in a food product, it must be explicitly mentioned in the ingredients list. If the label does not name the compound specifically, but simply says something like contains artificial color, then you know it does not contain one of the colors listed above. 

Colorimetry, See Analytical techniques Combustion chemistry, 40 products, 41, 42, 502 spontaueous, 18, 41, 43, 214, 216 Communicatious, 427, 428 Compound specific analyzers, 311 Compressed gases colour coding, 271 construction materials, 266 first aid measures, 280 hazards, 265 precautions, 272, 403 

Particularly for direct microanalytical techniques using <10 mg of sample for analysis, it is highly desirable to obtain quantitative information on element- and compound-specific homogeneity in the certificates for validation and quality control of measurements. As the mean concentration in a CRM is clearly material-related, the standard deviation of this mean value should represent the element s distribution in this matrix rather than differences in the analytical procedures used. 

Oxygen, the second requirement for combustion, is generally not limiting. Oxygen in the air is sufficient to support combustion of most materials within certain limits. These limitations are compound specific and are called the explosive limits in air. The upper and lower explosive limits (UEL and LEL) of several common materials 

An anaerobic bacterial enrichment cnltnre was used to examine the dechlorination of 2,3,4,5-tetrachlorobiphenyl that prodnced 2,3,5-trichlorobiphenyl exclusively. Although there was no alteration in the valnes of 5 C, compound-specific analysis of Arochlor 1268 showed that there was a trend for decreasing C abundance with increasing content of chlorine. This is consistent with dechlorination of the congeners with more chlorine substituents. 

This can be described in terms of the Anderson proposition specialized for the present application, which states that certain properties of a macroscopic disordered alloy will be qualitatively different from those of an intermetallic compound. Specifically, the charges on a Cu or Zn atom in one of these alloys will take on a continuum of values. Once this is understood, it must be said that there will be applications in which it is a good approximation 

Liquid Viscosity The viscosity of both pure hydrocarbon and pure nonhydrocarbon hquids are most accurately predicted by the method of van Velzen et al. The basic equation (2-112) depends on group contributions which are dependent on stnic tiire for the calculation of compound-specific constants B and To- 

Of more chemical interest is the synthesis of radioactive " C compounds from " C02 which is conveniently stored as a carbonate. " C is generated by an (n,p) reaction on a nitride or nitrate in a nuclear reactor (see p. 1256). More than 500 compounds specifically labelled with " C are now available commercially, the starting point of many of the syntheses being one of the following reactions  

The Subject Index of over 20 000 entries has been compiled from keywords, names and formulae in the text and tables. It covers general classes of compound, specific compounds, general types of reaction, specific and named reactions, spectral and other properties, and other topics in heterocyclic chemistry. More details are again given at the beginning of the index in Volume 8. 

At this stage we appreciate the relevance of small Cl -channels for hormonally regulated transepithelial Cl -transport (cf. sections 2.4 and 5). Unfortunately substances such as NPPB are rather poor inhibitors of these small Cl -channels. Therefore, new compounds specifically directed towards these channels will be required. Our search into this direction is still ongoing. 

Cyaneisen, n. iron cyanide, -kalium, n. potassium ferrocyanide, -verbindungt /. iron cyanogen compound, specif, a ferrocyanide. 

Peru-gummi, n. Peruvian gum. -rinde, /. Peruvian bark, -salpeter, m. Peruvian saltpeter (NaNOa). -silber, n. a kind of nickel silver, peruvianisch, a. Peruvian, of Peru. Perverbindimg,/. per compound, specif, peroxy compound. 

Platin-oxyd, n. platinum oxide, specif, platinic oxide, platinum(IV) oxide. -oxydul, n. platinous oxide, platinum(II) oxide, -oxy-dulverbindung, /. platinous compoimd, platinum (II) compound, -oxydverbindung, /. platinic compound, specif, platinum (IV) compound. 

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