Rapid screening techniques

Table 8.39 shows the main features of EDXRF. EDXRF is not able to detect the fine structure of the K, L, M, etc. lines. EDXRF is used for applications which require measurement of a limited number of elements, and where the resolution and ultralow detection limits of wavelength-dispersive systems are not necessary. For example, EDXRF has been used as a rapid screening technique for the determination of Br and Sb in plastic recyclate at a LOD of 5 ppm [230] the method was validated by means of NAA [231]. Conventional EDXRF systems and benchtop units have a limited detection capability for low-Z-elements and cannot directly measure fluorine in processing aids. 

Applications MALDI-ToFMS is at its best as a rapid screening technique for quick identification of known additives. However, this screening is rendered slightly more complicated by the fact that MALDI-ToFMS spectra of pure additives and of additives in the presence of excess macromolecules are not always identical (matrix effect) [55]. For unknown additives, the relation MALDI-ToFMS spectrum-chemical structure is not easily established, and the use of FD or MALDI-MS/MS is then needed. As MALDI-MS shows a sensitivity difference for the various additives, it cannot easily quantify them unless the analytes are very similar. For differentiation of additives with the same mass number (e.g. Tinuvin 315 and Cyasorb UV3638 with m/z = 368) high resolution is required, as provided by delayed extraction MALDI-ToFMS. 

It is concluded that MALDI-ToFMS is a suitable method for direct analysis of low-MW additives in complex polymeric materials (in dissolution), in particular as a rapid screening technique (within 0.5 h). However, in order to turn this method into a general tool for identification and quantitation, considerably more work needs to be done. Identification of additives in polymeric matrices by means of MALDI-ToFMS would greatly benefit from reference libraries of additives contained in such matrices. This is not unlike the situation observed for ToF-SIMS. 

Weber N, Bolikal D, Bourke SL, Kohn J (2004) Small changes in the polymer stmcture influence the adsorption behavior of fibrinogen on polymer surfaces validation of a new rapid screening technique. J Biomed Mater Res Part A 68A 496-503... 

Not only fatty acids but every unsaturated lipid molecule can undergo oxidation. So sterol oxidation products have also been studied in this case, HPLC is used both as a preparative step and for analytical purposes [33,34], HPLC as a preparative step was proposed by several researchers to improve the speed of analysis in the case of sterols, stigmastadienes, and waxes [35,36], Stigmastadiene, which is used as a marker in the refining process applied to vegetable oils, is determined by capillary GC however, the International Organization for Standardization (ISO) method (ISO 15788-2 2003) [37] uses HPLC as a rapid screening technique. 

Straub, K. M. Rudewicz, P. Garvie, C. 1987. Metabolic mapping of drugs rapid screening techniques for xenobiotic metabolites with m.s./m.s. techniques. Xenobiotica,17, 413-422. 

Organic FDR detection is a useful additional technique, despite the fact that single-based propellant constituents cannot be reliably detected. The current system uses GC/TEA as a rapid screening technique for NG and 2,4-DNT, and only positive samples need to be subjected to the SPE cleanup/ concentration procedure. The method is flexible in that the extract can be analyzed by a range of analytical instrumentation. There does not appear to be good correlation between the detection of organic and inorganic FDR which emphasizes the need for combined instrumentation, that is, GC/TEA, GC/MS, and SEM/EDX. Details of the method devised are as follows. 

Current developments in combinatorial chemistry and rapid screening techniques promote new systems in the field of polymer-supported catalysts (cf. Section 3.1.3) [279]. A drawback for this technology is still the leaching tendency of the catalyst which is clearly shown in recycling experiments (cf. Section 3.1.1.3) [280]. Polycondensation of organo-functionalized silanes and polysiloxanes leads to covalent support of catalyst on the surface, also known as the sol-gel process [281-283]. Van Leeuwen and co-workers reported a phosphine ligand with a xanthene backbone which was functionalized with a propyltrialkoxysilane... 

Borresen AL, Hovig E, Smith-Sorensen B, Malkin D, Lystad S, Andersen TI, et al. Constant denaturant gel electrophoresis as a rapid screening technique for p53 mutations. Proc Nad Acad Sci U S A 1991 88 8405-9. 

Hiller, D.L. et al., Rapid screening technique for the determination of optimal tandem mass spectrometric conditions for quantitative analysis, Rapid Commun. Mass Spectrom., 11, 593, 1997. 

The large scale cGMP synthesis of ABT-866 required reduction of the nitro group and hydrogenolysis of the acetate moiety of intermediate I. The palladium catalyzed hydrogenation of compound I was carefully studied in a systematic fashion for the effect of solvent, catalyst, pH, teirqierature, and concentration. Key to the success of our approach was the combination of rapid screening techniques and HPLC analysis. 

Test benchmark catalysts with half-cell rapid screening technique for their activity in the oxygen reduction reaction (ORR) and compare ranking of catalysts with their performance in polymer electrolyte membrane MEAs. 

Half-cell rapid screening technique for screening electrocatalysts for their ORR activity in place and benchmarked for various Pt-based electrocatalysts. 

Increase capacity of half-cell rapid screening technique to match the screening needs of CPSS powder generation capability. 

Continue to improve the structure and performance of the cathode layer and test the performance of newly discovered electrocatalyst compositions in MEA configuration that are identified by the rapid screening technique to have enhanced kinetic performance. 

In order to execute a combinatorial approach for discovery of novel electrocatalyst materials, several key workflow components need to be in place, including the ability to generate a large mrmber of electrocatalyst powders with variation in the composition and microstructure and to test their activity in the ORR by a rapid screening technique. 

Franks, J.P. and DeZeeuw, R.A. (1976). Differential pulse anodic stripping voltammetry as a rapid screening technique for heavy metal intoxication. Arch. Toxicol. 37, 47. 

Biomedical thermography [222] is used extensively as a thermal mapping technique to indicate a wide range of subcutaneous medical disorders. The first use of chiral nematics to indicate skin temperature was over 30 years ago [223]. Such devices are normally constrained to indicate temperature in the 30-33°C temperature range, over which the whole color play can be exhibited. Such films have been used to indicate breast cancer [224], for placental location [225], to identify vascular disorders [226], and for skin grafting [227]. The use of chiral nematics in such areas presents an inexpensive rapid screening technique which is only indicative, since local patient and environment conditions, e.g., room and patient temperatures and internal film pressure, may lead to some false readings. This is discussed in more detail in [97]. 

Already there are a number of biodiscovery programmes searching for new hyper-lipid producing strains (Mutanda etal., 2011). This, in turn, has led to efforts to develop methods for rapid screening techniques for naturally high Upid producers (Dean et al., 2010). 

Inhibition efficiencies of five inhibitor candidates at 10 M on AA2024-T3 (squares) and mild steel (circles) measured using the rapid screening technique plotted against the inhibition efficiencies obtained from potentiodynamic curves... 

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