Analytical Sciences

A New Laser Ablation System for Quantitative Analysis of Solid Samples with ICP-MS

Tomoharu ISHIDA,*¹ Takanori AKIYOSHI,*² Akiko SAKASHITA,*³ Satoshi KINOSHIRO,*⁴ Kyoko FUJIMOTO,*¹ and Atsushi CHINO*⁴

*1 Analysis & Characterization Research Dept., Steel Research Laboratory, JFE Steel Corporation, 1 Kawasaki, Chuo, Chiba 260-0835, Japan
*2 Standardization Center, The Japan Iron and Steel Federation, 3-2-10 Nihonbashi-Kayabacho, Chuo, Tokyo 103-0025, Japan
*3 Analysis & Characterization Division, JFE Techno-Research Corporation, 1-1 Minamiwatarida, Kawasaki 210-0855, Japan
*4 Analysis & Characterization Research Dept., Steel Research Laboratory, JFE Steel Corporation, 1-1 Minamiwatarida, Kawasaki 210-0855, Japan

The laser ablation (LA) method is an effective technique for quantitative analysis. In the present work, a new LA system was developed for the high-sensitivity analysis of metal materials using inductively coupled plasma mass spectrometry (ICP-MS). This system consists of a high-frequency Q-switched laser and 2 scanning mirrors for scanning the ablation spot in an adequately large area of the specimen without vacant spaces. The influence of elemental fractionation (non-stoichiometric generation of vapor species) can be eliminated by repetitive irradiation of this pattern on the same area. Particles generated with an average laser power of 0.6 W with the developed LA system gave intensity and stability substantially similar 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 performance of the newly-developed system is comparable to that of conventional solution ICP-MS in both accuracy and precision. The correlation coefficients between the contents and the intensity ratios to Fe were over 0.99 for most elements. The relative standard deviation (RSD) obtained by LA-ICP-MS revealed that this system can analyze iron samples with good precision. The results of ultra trace level analysis of high-purity iron showed that developed LA-ICP-MS is capable of analyzing ppm concentration levels with a 20 - 30 ppb level standard deviation. The detection limit was on the order of 10 ppb for most elements.

J-STAGE: View this article in J-STAGE