Arc ablation

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. 

For the direct analysis of steels by ICP-MS, Jiang and Houk [547] used arc ablation and reported detection limits at the 0.1 gg/g level and calibration curves being linear to concentrations of 0.1%. Arrowsmith and coworkers showed that both in metals as well as in ceramic samples direct analyses could be performed with... 

Various techniques have been employed to introduce solid samples directly into plasma. These techniques may be divided into two groups (1) direct insertion of samples into the plasma, and (2) methods that convert solid samples into an aerosol or a vapour, which is then transported into the plasma. The latter techniques include electrical spark and arc ablation, electrothermal vaporization, and laser ablation. 

In spark ablation, a spark at constant density is obtained in a matter of seconds, and thus, particularly in the case of small spark chambers, prebum times are accordingly low. In plasma emission as well as in plasma mass spectrometry a linear dynamic range of more than four orders of magnitude can be obtained and RSDs are a few percent in the case of absolute measurements. However, as shown by the results in Table 6, they can easily fall to below 1%, when using an internal standard element (Fe in the case of steel samples). The matrix effects from the sampling source are low, as will be shown in combination with ICP-OES (see Refs. [242, 248]). They are lower than in arc ablation, as here differences stemming from the thermal volatility of the elements and their compounds play a lesser role. The... 

Figure 1. Schematic presentation of plasma arc ablation test assembly (1) carrier platform, (2) TiB die, (3) sample, (4) plasma flame, (5) ablation gun, (6) support, (7) pyrometer, and (8) computer...

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