2006 Volume 55 Issue 4 Pages 229-236
The laser ablation (LA) method brings purposeful effect for quantitative analysis. A new LA system has been developed for inductively coupled plasma mass spectrometry (ICP-MS). This system consists of a high-frequency Q-switched laser and 2 scanning mirrors for moving the ablation spot in an adequate area without any vacant space. The influence of elemental fractionation (non-stoichiometric generation of vapor species) can be removed by repetitive radiation of this pattern on the same area. Particles generated with 0.6 W of average laser power in the developed LA system gave intensity and stability nearly equal to that of a 500 μg/ml solution steel sample in solution ICP-MS. The analytical performance of the developed LA-ICP-MS was compared with that of a solution ICP-MS using NIST steel SRMs. The developed system is no less than the usual solution ICP-MS in accuracy and precision. The correlation coefficients between the contents and the intensity ratios to Fe were over 0.99 in most elements. The relative standard deviation (RSD) obtained by LA-ICP-MS revealed that this system could analyze iron samples with good precision. The results of an ultra trace-level analysis of high-purity iron showed that the developed LA-ICP-MS was able to analyze ppm levels of concentration with a 20∼30 ppb level of standard deviation. The detection limits were 10 ppb levels in most elements.
