THERMOSPRAY DEVICE OF IMPROVED DESIGN FOR APPLICATION IN ICP-MS

A new thermospray device for sample introduction in ICP-MS has been de veloped, Three design principles were followed in order to minimize bl ank values which originate from chemical erosion of the utilized mater ials: the aerosol comes exclusively in contact with chemically inert m aterials; a fused silica capillary is used instead of the usually appl ied steel capillary; and a double desolvation system is applied for an effective reduction of the solvent load to the plasma, With careful o ptimization of the temperature of the capillary, aerosol gas flow rate , sample uptake rate, operation of the desolvation system and the ICP, a considerable improvement was achieved. Blank values in the mass reg ion of Fe, as appear with steel capillaries, were reduced by orders of magnitude, so that this important region became accessible for analyt ical determination with satisfying detection limits, Sensitivity,vas i mproved by a factor of about 20 for the elements measured in compariso n with two commercial pneumatic nebulization systems and ICP-MS instru ments with low and high resolution, Standard deviations of less than o r equal to 3.8%, and about 10 times lower detection limits in the mean were achieved for a variety of elements in comparison with pneumatic nebulization. In spite of remaining restrictions from blank values, de tection limits at pg ml(-1) levels and below were realized for several elements.