Analysis target

High resolution is used to determine the exact mass of an ion species in a mixture knowledge of the exact mass of an unknown substance allows its atomic composition to be established. Target analysis exact mass determination proves the presence of a particular ion species (compound) in a mixture. Mass spectrometry is perhaps the only method that can be used to find the empirical formulae of compounds that are not completely pure. 

GCxGC is most often applied for target analysis. Main application areas for GCxGC are to be found where unresolved peaks are the norm, i.e. for atmospheric organics (e.g. urban air), food and flavour (organoleptics), (petro)chemical and forensic analyses,... 

Peltier, J. B., Friso, G., Kalume, D. E., Roepstorff, P., Nilsson, F., Adamska, I., and van Wijk, K. J. (2000). Proteomics of the chloroplast systematic identification and targeting analysis of lumenal and peripheral thylakoid proteins. Plant Cell 12, 303-304. 

Selective biocapture, such as with immobilized antibodies, adhesions or carbohydrates, can be used to concentrate targeted analysis online or in... 

Brederode ME, Jones MR, Van Grondelle R (1997) Primary electron transfer kinetics in membrane-bound Rhodobacter sphaeroides reaction centers a global and target analysis. 

LANGE, B.M., KETCHUM, R.E.B., CROTEAU, R., Isoprenoid biosynthesis metabolite profiling of peppermint oil gland secretory cells and application to herbicide target analysis, Plant Physiol., 2001,127, 305-314. 

Hogenboom A.C., Niessen W.M.A., and Brinkman U.A., 1998. Rapid target analysis of microcontaminanant in water by online single-short-column liquid chromatography combined with atomospheric pressure chemical ionization ion-trap mass spectrometry. J Chromatogr A 794 201. 

Mobile, on-line XRF methods have been tested in the Au exploration targets. Analysis of continuous till and weathered bedrock samples shows clear variation of the contents of pathfinder elements of hydrothermal alteration. Particularly, in the weathered bedrock, the presence of narrow mineralized veins is seen (Fig. 5). One interesting feature is that the indication of the weathered bedrock sources can be traced 2 to 5 m down-ice in the till. These results suggest very short glacial transport of mineralized debris from the bedrock sources. Information on... 

Perezarantegui, J., Querre, G., and Castillo, J. R. (1994). Particle-induced X-ray-emission -thick-target analysis of inorganic materials in the determination of light-elements. Journal of Analytical Atomic Spectrometry 9 311-314. 

Once the causal factors have been identified, the factors are analyzed using a root cause analysis tool, such as 5-AVhys or predefined trees. See Chapter 9 for a more detailed discussion of Barrier Analysis (sometimes called hazard-barrier-target analysis or HBTA) and Change Analysis (also referred to as Change Evaluation/Analysis or CE/A). In essence, these tools act as a filter to limit the number of factors, which are subjected to further analysis to determine root causes. 

The design of most process plants relies on redundant safety features or layers of protection, such that multiple layers must fail before a serious incident occurs. Barrier analysis ) (also called Hazard-Barrier-Target Analysis, HBTA) can assist the identification of causal factors by identifying which safety feature(s) failed to function as desired and allowed the sequence of events to occur. These safety features or barriers are anything that is used to protect a system or person from a hazard including both physical and administrative layers of protection. The concepts of the hazard-barrier-target theory of incident causation are encompassed in this tool. (See Chapter 3.)... 

Figure 1.8 Gene expression of off-target analysis using microarrays.

Tzeng, C.M. Kornberg, A. The multiple activities of polyphosphate kinase of Escherichia coli and their subunit structure determined by radiation target analysis. J. Biol. Chem., 275, 3977-3983 (2000)... 

All data sets are analysed using global analysis [[3],[4]]. Since part of the noise is correlated, i.e. baseline noise or amplitude noise of the whole spectrum, this kind of analysis is excellently suited to extract more reliable information from the data than a single-trace analysis. If the data contains sufficient information, or extra information is available, a target analysis is applied (i.e. a specific model is fitted to the data) from which spectra of physical states result. 

Lane, S. J., and Pipe, A. (2000). Single bead and hard tag decoding using accurate isotopic difference target analysis-encoded combinatorial libraries. Rapid Commun. Mass Spectrom. 14 782-793. 

Unlike, e.g. in pharmaceutical metabolism studies, where the parent compound is known and thus some preliminary knowledge of the expected structures is available, the composition of a natural products extract is often completely unknown beforehand ( non-target analysis ). In such cases, NMR spectroscopy is especially well suited as a detection system since it does not discriminate any classes of compounds. (Sufficient relaxation delays provided, the NMR signal depends only on the number of nuclei in the active probe volume.)... 

In the case of degradation products and metabolites, the situation is different. Generally, these compounds were not analysed because in most cases they are not regulated and no effective analytical methods exist for their determination. This means that a correct diagnosis of the environmental situation cannot be made and, as a consequence, no appropriate action can be taken. Therefore, in order to improve the risk assessment of a hazardous waste site for example, as many compounds as possible should be analysed at the beginning of the investigations (non-target analysis). 

---