TRACE ANALYSIS OF GLASSES BY MAGNETICALLY ENHANCED RF GDMS

A radiofrequency (rf) glow discharge ion source coupled to a commercia l double-focusing mass spectrometer was used for the direct trace elem ent analysis of glass samples. By utilizing an additional ring-shaped magnet located behind the flat sample in an rf glow discharge ion sour ce 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 elemen ts determined by rf glow discharge mass spectrometry at low mass resol ution (m/Delta m = 300) are 10-100 ng/g. Possible interferences of ato mic 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/Delta m = 3000. The detection limits for t hese elements were found to be about 100 ng/g. Relative sensitivity fa ctors (RSFs) for all elements of interest with respect to Sr (internal standard element) were determined in the range of 0.2-3.