Analytical Sciences

Abstract − Analytical Sciences, 25(2), 161 (2009).

Improvement of Analytical Sensitivity by Ar-N2 Inductively Coupled Plasma in Axially Viewing Optical Emission Spectrometry
Masaki OHATA,* Yuichi TAKAKU,** Kazumi INAGAKI,* Akiharu HIOKI,* and Koichi CHIBA*
*National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
**Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho-mura, Kamikita-gun, Aomori 039-3212, Japan
The analytical sensitivities of elements were improved by Ar-N2 inductively coupled plasma (Ar-N2 ICP) in axially viewing optical emission spectrometry (OES). A commercially available ICP-OES instrument was used, and only N2 gas was added at flow rates of up to 1.0 L min-1 into Ar plasma gas. A stable Ar-N2 ICP was obtained, and the net signal intensities of elements were enhanced by factors of up to 25 compared to those observed for Ar ICP-OES. The detection limits evaluated were also improved by factors from 5 to 10, especially for elements with relatively higher ionization energies. Moreover, the analytical sensitivities for these elements observed in axially viewing Ar-N2 ICP-OES were superior to those in radially viewing Ar-N2 ICP-OES reported previously. The Ar-N2 ICP is expected to be a useful alternative source for excitation and ionization in axially viewing ICP-OES.