J. Pisonero et al., A simple glow discharge ion source for direct solid analysis by on-axis time-of-flight mass spectrometry, J ANAL ATOM, 16(11), 2001, pp. 1253-1258
A simple and small-sized direct current glow discharge (dc-GD) ion source h
as been designed and constructed for direct analysis of solid samples. The
glow discharge (about 100 mm(3) of internal volume) was coupled to a commer
cial on-axis time-of-flight mass spectrometer (TOFMS) for fast simultaneous
multielement-selective detection. The commercial TOFMS used was originally
coupled to an inductively coupled plasma (ICP) ion source. Therefore, the
GD source presented in this study was designed aiming at being easily excha
nged with the ICP source of a commercial ICP-TOFMS instrument (LECO Corpora
tion). The distance between the cathode (sample) and the sampler cone was k
ept at about 4 mm. The proposed source is able to analyse planar conducting
samples of different sizes with good long-term stability (better than +/-5
% when isotope ratioing techniques were applied). The spectral mass resolvi
ng power was about 1520 (at mass 120 u). Finally, the expected benefits of
the fast simultaneous multielemental capabilities of TOFMS detection to car
ry out direct depth profile analysis of solid samples are demonstrated and
discussed.