Species analysis

Analytical applications Mass spectrometry has been applied to a variety of analytical problems related to expls, some of which have already been mentioned. Identification of the principal constituents of expls has been attempted from electron impact cracking patterns (Refs 34, 50 58), as well as chemical ionization spectra (Refs 69,70 71). Such methods necessarily include vapor species analysis and are directed to detection of buried mines (Refs 50, 58, 61,... 

Kaneda, K. Molecular species analysis of mycolic acids in acid-fast bacteria. Iyo Masu Kenkyukai Koenshu 1987,12, 63-70. 

The different ways of species analysis - qualitative and quantitative - are well known. However, in structure analysis, they can also be differentiated between qualitative and quantitative ways according to the type and amount of information obtained (Eckschlager and Danzer [1994]). Identification of a sample or a given constituent may have an intermediate position between species and structure analysis. In any case, identification is not the same as qualitative analysis. The latter is the process of determining if a particular analyte is present in a sample (Prichard et al. [2001]). Qualitative analysis seeks to answer the question of whether certain components are present in a sample or not. On the other hand, identification is the process of finding out what unknown substance(s) is or are present (Eckschlager and Danzer [1994]). In Sects 9.1 and 9.3 it will be shown that there is a... 

On the other hand, when latent variables instead of the original variables are used in inverse calibration then powerful methods of multivariate calibration arise which are frequently used in multispecies analysis and single species analysis in multispecies systems. These so-called soft modeling methods are based, like the P-matrix, on the inverse calibration model by which the analytical values are regressed on the spectral data ... 

The present volume of the series focuses on the interplay between organisms and the physical chemistry of the environmental media in which they live. It critically discusses the different physicochemical and biophysical features of the kinetics of processes at the biointerface, with special attention given to aspects such as bioavailability of chemical species, analysis of the necessary mass transfer towards/from the biointerface, routes of transfer through the biomembrane, etc. This volume was realised within the framework of the activities of the former IUPAC Commission on Fundamental Environmental Chemistry of the Division of Chemistry and the Environment. We thank the IUPAC officers responsible, especially the executive director, Dr John Jost, for their support and assistance. We also thank the International Council for Science (ICSU) for financial support of the work of the Commission. This enabled us to organise the discussion meeting of the full team of chapter authors (in Diibendorf, Switzerland, 2001) which formed such an essential step in the preparation and harmonisation of the various chapters of this book. 

The certification procedure for seven trace metals (Ba, Ca, Li, Mg, Mn, Na and Sr) in the certified reference material FEBS-1 (National Research Council Canada, Institute for National Measurement Standards, Ottawa, Canada) based on fish otolith matrix by isotope dilution - ICP-MS in comparison to ICP optical emission spectrometry and X-ray fluorescence analysis, is described by Sturgeon et al4X The isotope dilution technique is also employed for species analysis in biological systems,46 e.g., for the determination of mercury species in tuna material,54 or in aquatic systems using cold vapour ICP-MS.55... 

In general it has to be stated that molecular species analysis of phospholipids is not frequently applied in food analysis most of the studies involving molecular species are instead found in the fields of biochemistry and nutrition. Thus, in the recent reviews by Bell and by Olsson and Salem, special emphasis has been given to the characterization of biological tissue samples (83,84). However, the molecular species composition has been shown to affect the accuracy of the quantification of phospholipid classes and hence is important in food analysis too (47,52). In the vast majority of published methods, isocratic elution has been used. In our opinion, this should be ascribed mainly to the fact that the traditional UV detector remains. Keeping account of the inherent problems associated with UV detection of underivatized phospholipids, it is astonishing that ELSD has hardly been exploited in this subdomain. As far as the stationary phase is concerned, nearly all methods prefer octadecyl-coated stationary phases. 

Traditionally, UV detection was by far the most widely used detection method, both in phospholipid class analysis and in molecular species analysis. Even up to now, this detection system re-... 

NU Olsson, N Salem Jr. Molecular species analysis of phospholipids. J Chromatogr B 692 245-256, 1997. 

Miller, N.G., Hill, M.W. and Smith, M.W. (1976). Positional and species analysis of membrane phospholipids extracted from goldfish adapted to different environmental temperatures. Biochimica et BiophysicaActa 55,644-654. 

On the other hand, the Curie-Weiss behavior is fully suppressed in the LS phase below 48 K. It suggests that the complete C3-symmetry is recovered in the LS molecule and the reorienting dipoles, which are required to guarantee the apparent C3-symmetry in the dynamically disordered HS phase, disappear. A slight growth of s observed between 15 and 40 K arises from a small fraction of thermally excited HS species. Analysis of this part assuming a temperature dependence of the... 

This reaction is essentially thermoneutral. Although we lack enthalpy of formation data for the corresponding 1,3-benzodithiole, the weakness of 1,3 sulfur-sulfur interactions as manifest by the near equality [52] of the enthalpies of formation of 1,3- and 1,4-dithiane (unlike 1,3- and 1,4-dioxane) suggests no special interaction in this nonaromatic heterocycle. Said differently, the thermoneutrality of the above reaction, as opposed to profound exothermicity (21 kJ mol ) for indane (six n electrons) and the endothermicity (29 kJ mol1) for benzimidazolinone (ten n electrons), suggests phenylene trithiocarbonate (ten n electrons) has an intermediate degree of aromaticity. For the latter two species, analysis of the related reactions ... 

The term speciation , according to Bernhard et al. (1986a), encompasses three aspects (1) the actual distribution among molecular level entities in a given matrix, (2) the processes responsible for an observable distribution (species distribution), and (3) the analytical methods used (species analysis). Aspects (1) and (3) are compatible with the definition given by Ure (1990) and presented in Chapter 1. The second aspect, (2) above, is now seldom used in chemistry and... 

Tier-4 Whole-SSD Curve-Based Approaches for Species Level with Mode of Action and Exposed Species Analysis... 

The recent availability of tunable dye lasers has markedly enhanced our ability to inquire into the chemistry and physics of combustion systems. The high sensitivity, spectral and spatial resolution, and non-perturbing nature of laser induced fluorescence makes this technique well suited to the study of trace chemistry in complex combustion media. A barrier to the quantitative application of fluorescence to species analysis in flames has been the need to take into account or bypass the effects of quenching. The use of saturated fluorescence eliminates quenching as a problem and has the further advantage that fluorescence intensity is insensitive to variations in laser power (1, 2 ). However, the generation of high concentrations of excited states under saturated excitation in an active flame environment opens up the possibilities for laser induced chemistry effects that also must be taken into account or avoided (3,4,5). 

The product analysis of the DNA-polymerase reaction (FLV) in the absence and in the presence of tilorone (1 x 10-4 M) is depicted in Fig. 10. The products of the viral DNA-polymerase reaction were, under these conditions, eluted in three species. The first species to be eluted from the column contained ss-DNA, the second contained the RNA-DNA hybrid-molecules (hy-DNA) and finally, the ds-DNA, eluted in the last species. Analysis of products synthesized in the presence of tilorone showed that the ss-DNA and the hybrid species, but not the ds-DNA species were synthesized. This indicates that tilorone has a low affinity to viral RNA, but can block the synthesis of ds-DNA by interacting with ss-DNA or hy-DNA. 

The principle of the isotope dilution analysis (IDA) is described in Section 6.4. Due to its advantages as a definitive and accurate analytical method for the determination of element concentration via isotope ratio measurements, IDA is being increasingly applied in mass spectrometry, especially in ICP-MS and LA-ICP-MS as one of the most frequently used techniques. For example, the isotope dilution technique is employed in species analysis in biological systems, " e.g., for the determination of mercury species in tuna material,or in aquatic systems. Further applications of the isotope dilution technique are the determination of selenomethionine in human blood serum by capillary HPLC-ICP (ORC) MS ° or sulfur speciation in gas oil, diesel or heating fuel by LA-ICP-MS. Evans and co-workers have reported on the high accuracy analysis of sulfur in diesel fuel by IDA. ICP-SFMS has been employed for Si species analysis in biological or clinical samples and... 

Furthermore, online chromatographic coupling techniques such as HPLC and CE coupled to ICP-MS with the isotope dilution technique have been used for element quantification in specia-tion analysis. Species analysis by ICP-SFMS in medical research has been performed by Prange et a/. on separated isoforms of metallothionein (e.g., of rabbit liver) by capillary electrophoresis (CE). For quantitative determination of S, Cd, Cu and Zn in isoforms, highly enriched " S, Cu, Zn and Cd spikes are added to the analyte solution in the interface region of CE. 

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