FOURIER-TRANSFORM ATOMIC EMISSION-SPECTROMETRY WITH A GRIMM-TYPE GLOW-DISCHARGE SOURCE

Analytical atomic emission spectrometry (AES) is pursued by using a Grimm-type glow-discharge source (GDS), equipped with an electrically floating restrictor tube (internal diameter: 8.0 mm) and operated at 110-225 W/cm2 and 400-600 Pa argon pressure. Amplitude noise spectra of the GDS emission, obtained by a fast Fourier transform, exhibit discrete noise peaks which result from the vacuum-pump system (10-20 Hz) and the power line (60, 120 Hz). Additional noise peaks (at 50 Hz, 80 Hz and 350 Hz) were noted but their origin could not be identified. White noise was found to be dominant in most frequency regions, especially for minor-element lines or for the spectral background. It is shown that combining a Grimm-type glow-discharge source with a high-resolution Fourier transform spectrometer is a potentially attractive approach for flexible multielement analyses of solid samples. The spectral widths of the analytical lines are in the pm range. For the case of molybdenum in steel, the limit of detection of glow-discharge Fourier transform-atomic emission spectrometry extends to approximately the 30 μg g level. © 1990.