Analytical Sciences

Development of the Atmospheric Plasma Soft-Ablation Method (APSA) for Elemental Analysis of Materials on Heat-sensitive Substrates

Takahiro IWAI, Yuichiro TAKAHASHI, Hidekazu MIYAHARA, and Akitoshi OKINO

Department of Energy Sciences, Tokyo Institute of Technology, J2-32, 4259 Nagatsuta-cho, Midori, Yokohama 226-8502, Japan

To achieve a highly sensitive and prompt elemental analysis of materials on heat-sensitive substrates, like living tissues, the atmospheric plasma soft-ablation method (APSA) was developed. The damage-free plasma, which has room temperature and no risk of electrical shock, was used as a sampling medium for materials, and the sampled materials were introduced to inductively coupled plasma mass spectrometer (ICP-MS). By using APSA, a mass signal of molybdenum, using a thin molybdenum-grease layer, was successfully obtained without damaging the subjacent glass substrate. The use of a hydrogen admixture to generate the plasma was examined in order to achieve more effective sampling by utilizing chemical reactions between radicals in the plasma and the sample material. As a result, the sensitivity of all measured elements contained in tablet supplements increased by up to 20 times upon the addition of 1% hydrogen, even though the plasma-gas temperature did not change significantly.

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