Improvement of Analytical Sensitivity by Ar-N2 Inductively Coupled Plasma in Axially Viewing Optical Emission Spectrometry

The analytical sensitivities of elements were improved by Ar-N-2 inductively coupled plasma (Ar-N-2 ICP) in axially viewing optical emission spectrometry (OES). A commercially available ICP-OES instrument was used, and only N-2 gas was added at flow rates of up to 1.0 L min(-1) into Ar plasma gas. A stable Ar-N-2 ICP was obtained, and the net signal intensities of elements were enhanced by factors Of Lip 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-N-2 ICP-OES were superior to those in radially viewing Ar-N-2 ICP-OES reported previously. The Ar-N-2 ICP is expected to be a useful alternative Source for excitation and ionization in axially viewing ICP-OES.