Calibration with transient signals

Figure 9.23 Determination of RE-ADH by lA-tCP-SFMS (a) transient signals in ID gels with different amounts of RE-ADH from 1.5 to 12pg, (b) corresponding ID calibration gel of RE-ADH, (c) part of ID gel with unknown amount of RE-ADH - native protein and possibly denaturized RE-ADH protein, (d) the calibration curve for 66Zn in RE-ADH after measurements of transient signals in ID gel in (b).

Direct sample insertion allows the direct analysis of used oils [222] and of microamounts of sediments [226] as well as the determination of volatile elements in refractory matrices [224]. Difficulties lie in the calibration and in the signal acquisition. The latter necessitates a simultaneous and time-resolved measurement of the transient signals for the line and background intensities to be made in trace analysis. This may become easier when applying CCD detection with the appropriate software. Also in the case of direct sample insertion the use of thermochemical reagents has been found to be usefiil [469]. An extremely sensitive technique lies... 

Figure 11.7. (A) After excitation, the summation of all ions trapped within the analyzer cell produces a transient signal that is digitized and stored by the data system. A fast Fourier transform (FFT) is applied to the transient (B), producing a frequency spectrum that is then converted into a mass spectrum via a calibration equation. (Reprinted from Ref. 161 with permission.)...

As a rule calibration in furnace AAS is done by standard additions, as many of the interferences mentioned cause specific changes to the slope of the calibration curves. This makes sense as background changes can be readily measured through different techniques and in all cases with a sufficient time resolution to cope with the transient nature of the analytical signals and of the background absorption as well. 

Fig. 4.19. (a) Transient chemiluminescence signal as recorded with P3HT PCBM photodetector for different hydrogen peroxide concentrations (oxidation reagent), (b) Calibration plot for steady-state signal (From [21] - Reproduced by permission of The Royal Society of Chemistry)... 

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