DIRECT ANALYSIS OF STEELS BY INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY WITH A CW Q-SWITCHED ND-YAG LASER

A cw Q-switched Nd:YAG laser has been applied to a laser ablation system for the direct analysis of steels by inductively coupled plasma mass spectrometry (ICP-MS). The YAG laser used produced fine particles (particles size, about 0.02-mu-m) at relatively high ablation rate (maximum 22-mu-g s-1); and that was important feature to improve sensitivity and precision. Selective vaporization of volatile elements was occurred in the ablation process, but the magnitude was low. The use of iron as an internal standard was effective to improve accuracy and precision. Good accuracy was obtained for trace elements such as B, As, Nb, Sn and so on. On the other hand, precision ranged from 5 to 10 (RSD, %) for the most of elements (isotope contents, 10 approximately 200-mu-g g-1). Detection of Si, Al and P were problematic due to molecular interferences and some contaminations in ICP-MS measurement. But the limits of other 14 elements were excellent (0.01-mu-g g-1 for Nd approximately 5.6-mu-g g-1 for Ni at the effective integrating time of 0.18 s). It was found that the laser ablation analysis without standards has enough accuracy to apply semiquantitative analysis.