Nudepore filter

When sparks are used for the ablation of electrically conducting solids, less changes with variations in the matrix composition than in the case of arc ablation occur. This is due to the fact that thermal volatilization plays less of a role. However, in the case of brass, it is seen from x-ray analyses of the ablated material on a Nudepore filter, for samples of the crater wall and the burning crater, that zinc volatilizes more than copper (Table 5), which makes the method difficult to apply to these samples. 

Work with slurries requires that the slurries are first nebulized and behave just as solutions with respect to the sample introduction into the aerosol. From electron probe micrographs of aerosol particles sampled on Nudepore filters under isokinetic conditions, it was found that at nebulizer gas flows of 3 L/min, being typical of plasma spectrometry but far below those for flame atomic absorption, particles with a diameter of up to 15 pm can be found in the aerosol (Fig. 44) [117]. This would imply that powders with a grain size of up to about 15 pm could still be nebulized as could a solution. This, however, is not true as the mass distribution in the case of powders may be quite different in the slurry and in the aerosol, as shown for the case of SiC (Fig. 45) [118]. The nebulization limitations for the case of slurry nebulization thus must be investigated from case to case and leads to certain types of restrictions. 

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