Trace analysis of glasses by magnetically enhanced rf GDMS

A radiofrequency (rf) glow discharge ion source coupled to a commercial double-focusing mass spectrometer was used for the direct trace element analysis of glass samples. By utilizing an additional ring-shaped magnet located behind the flat sample in an rf glow discharge ion source compared with a configuration without a magnet, the sputtering and ionization efficiency of glass samples was enhanced and the detection power for trace elements was improved. The detection limits for elements determined by rf glow discharge mass spectrometry at low mass resolution (m/Δm = 300) are 10–100 ng/g. Possible interferences of atomic ions of analyte and molecular ions which limited the determination of some elements (e.g. Ti, Mn, Fe, Ni, Co, Cu, Zn) could be resolved at the mass resolution of m/Δm = 3000. The detection limits for these elements were found to be about 100 ng/g. Relative sensitivity factors (RSFs) for all elements of interest with respect to Sr (internal standard element) were determined in the range of 0.2–3.