Analyte line physical width

Accordingly, it was very soon found that using sources for which the physical widths of the emitted analyte lines are low is more attractive. This is necessary so as to obtain high absorbances, as can be understood from Fig. 76. Indeed, when the bandwidth of the primary radiation is low with respect to the absorption profile of the line, a higher absorption results from a specific amount of analyte as compared with that for a broad primary signal. Primary radiation where narrow atomic lines are emitted is obtained with low-pressure discharges as realized in hollow cathode lamps or low-pressure rf discharges. Recently, however, the availability of narrow-band and tunable laser sources, such as the diode lasers, has opened up new per-... 

Cu, oo describes the influence of the radiation source, (dfJy/dl) is the spectral radiation density for the background intensity, B0 is the radiant density for an analytical line at the concentration c = 1 and A7L is the physical width of the analysis line. The second term (Ai) describes the influence of the spectral apparatus. 

As I line at 228.812 nm with the Gd I line at 228.802 nm. In such a case, an alternative line should be used. However, this may also be problematic if the analyte has few sensitive lines, as in the case of cadmium. When a higher resolution spectrometer, such as an echelle spectrometer, is used the lines are farther apart than their physical widths. However, interference is still possible through broadened line wing overlap or stray light. 

For a new process plant, calculations can be carried out using the heat release and plume flow rate equations outlined in Table 13.16 from a paper by Bender. For the theory to he valid, the hood must he more than two source diameters (or widths for line sources) above the source, and the temperature difference must be less than 110 °C. Experimental results have also been obtained for the case of hood plume eccentricity. These results account for cross drafts which occur within most industrial buildings. The physical and chemical characteristics of the fume and the fume loadings are obtained from published or available data of similar installations or established through laboratory or pilot-plant scale tests. - If exhaust volume requirements must he established accurately, small scale modeling can he used to augment and calibrate the analytical approach. 

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