Elemental and isotopic analysis of powders by inductively coupled plasma mass spectrometry with arc nebulization

A powdered sample is mixed with graphite and pressed into a conducting pellet. The pellet is eroded by an intermittent arc, and the resulting sample particles are injected into an inductively coupled plasma mass spectrometer (ICP-MS). This provides rapid survey analysis and determination of elemental and isotope ratios without dissolution of the sample. Small peaks for ArC+, Ar0+, and Ar2+ are the only species detected in the background spectrum above m/z 45. The absence of nebulized water effectively suppresses formation of metal oxide ions. Detection limits are 30-50 μg g-1 for the elements studied. Isotopic ratios may be determined with a precision of approximately 1% relative standard deviation for major constituents. Various rare earth elements are determined quantitatively at 0.1-1% levels in the original sample. (author)