D2-lamp technique

Fig. 86. Principle of background correction diagram of an atomic absorption spectrometer with the D2-lamp technique (A), AX spectral with D2 lamp for background correction (b) bandwidth of monochromator, BG non- (Model 2380) (Courtesy of PerkinElmer...

Figure 35. Background correction with the D2 lamp technique...

Zeeman AAS has several analytical advantages. The accuracy of correction of a structured background is better than with the D2 lamp technique. However, when the background structure stems from molecular bands, it must be remembered that molecular bands may also display a Zeeman effect. Systematic errors resulting from this fact may be larger when one line component is measured in an alternating field. 

With this technique, problems may arise with interference, such as background absorption—the nonspecific attenuation of radiation at the analyte wavelength caused by matrix components. To compensate for background absorption, correction techniques such as a continuous light source (D2-lamp) or the Zeeman or Smith-Hieftje method should be used. Enhanced matrix removal due to matrix modification may reduce background absorption. Nonspectral interference occurs when components of the sample matrix alter the vaporization behavior of the particles that contain the analyte. To compensate for this kind of interference, the method of standard addition can be used. Enhanced matrix removal by matrix modification or the use of a L vov platform can also reduce nonspectral interferences. Hollow cathode lamps are used for As, Cu, Cr, Ni, Pb, and Zn single-element lamps are preferred, but multielement lamps may be used if no spectral interference occurs. 

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