Abstract
With a low-power radio-frequency generator (1.8kW, 27.12MHz), N2 and O2 plasmas were obtained by slightly modifying the load coil and matching circuit. After the Ar plasma was generated, the outer and carrier gases of Ar were gradually replaced by N2 or O2. The replacement of the intermediate Ar gas by N2, however, was impossible. The detection limits of inductively coupled mass spectrometry with the N2 and O2 plasmas, in which the outer and carrier gases were 100% N2 and O2, respectively, were comparable or lower for the elements with ionization potentials lower than 6.5eV, but generally higher for the other elements, compared to those obtained with the Ar plasma. Polyatomic ions resulting from Ar, such as ArO+and Ar2+, were considerably attenuated with the N2and O2 plasmas, although the intensities of ArN+and analyte oxide ions increased with these plasma, respectively.
