Chemical signals typical intensity

Molecular ions are observed in spectra from rare earth metals with ion intensities similar to non-rare earth samples. Table 37C.2 lists typical intensity relationships observed in rare earth metal spectra for oxygen, fluorine, and carbon impurities and their associated matrix cluster ion intensities. Although the source of these ions relative to the solid sample has been studied by Muheim (1972, 1973), certain facets of their character remain clouded. Their intensities tend to be erratic and depend upon many parameters such as non-metallic impurity content, residual gas level in the spectrometer ion source chamber, contaminants on the surface of the metal sample, chemical environment, etc. The analytical usefulness of these cluster ion signals has not been established. 

PS (blue) and the sum of the most typical intensities signals of P2VP (red). TIC, total ion current (d) ToF-SIMS chemical maps refer to the film obtained by the 1/15 weight ratio P2VP-PS mixture. Reproduced with permission from Ref [22]. 

Whereas the use of conventional fast atom bombardment (FAB) in the analysis of polymer/additive extracts has been reported (see Section 6.2.4), the need for a glycerol (or other polar) matrix might render FAB-MS analysis of a dissolved polymer/additive system rather unattractive (high chemical background, high level of matrix-, solvent- and polymer-related ions, complicated spectra). Yet, in selected cases the method has proved quite successful. Lay and Miller [53] have developed an alternative method to the use of sample extraction, cleanup, followed by GC in the quantitative analysis of PVC/DEHP with plasticiser levels as typically found in consumer products (ca. 30 %). The method relied on addition of the internal standard didecylphthalate (DDP) to a THF solution of the PVC sample with FAB-MS quantitation based on the relative signal levels of the [MH]+ ions of DEHP and DDP obtained from full-scan spectra, and on the use of a calibration curve (intensity ratio m/z 391/447 vs. mg DEHP/mg DDP). No FAB-matrix was added. No ions associated with the bulk of the PVC polymer were observed. It was... 

The typical profile of a CL transient signal (a plot of CL intensity vs. time) is a kinetic response curve that corresponds to a first-order sequence of two consecutive steps, namely (1) generation of the light-emitting product by mixing of the chemical ingredients (the substrate and oxidant), and (2) formation of the end product (Fig. 2). The rate at which each step takes place depends on the formation... 

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