Some Near-IR Spectral Emission Characteristics of the Inductively Coupled Plasma

Several spectrochemical measurement systems have been used for the characterization of near-IR emission spectra from the inductively coupled plasma, with particular emphasis on the determination of sulphur. Background emission spectra of Ar and N₂/Ar ICPs and the emission spectrum of dimethylsulphoxide (DMSO) are presented and the major emission lines of Ar, N, C, O and S are tabulated. These measurements and data cover the spectral region from about 3 µm to 0.7 µm and were obtained using a Fourier transform spectrometer. Detection limits for the determination of sulfur using a monochromator in combination with either a Si photodiode, a Si photodiode array or a PbS detector at the 0.922 and 1.046 µm lines are presented. The best detection limit (20 ppm) was obtained with the Si photodiode detector at the 0.922 µm line.