Signal enhancements produced from externally generated ‘carrier’ particles in electrothermal vaporization-inductively coupled plasma mass spectrometry

An externally generated carbon particle aerosol produced from the pyrolysis of hexane vapor was introduced into an electrothermal vaporization inductively coupled plasma mass spectrometer (ETV-ICPMS) system in order to probe possible ‘carrier’ effects. Signal enhancements were seen upon the introduction of the externally generated aerosol for most metals studied. However, these enhancements were determined to be caused by changes in the plasma rather than increased transport from the ETV to the ICPMS. Because a pyrolyzed hydrocarbon was used to generate the aerosol, both hydrogen gas and carbon were introduced into the plasma. The source of the enhancements is believed to stem from an increased plasma temperature (from H2(g) addition) which increases the kinetic energy of the ions and enhances the transmission through the ion lenses. The carbon may also contribute to improved ionization efficiencies for those analytes with ionization potentials between 8.5 and 11 eV. Thus, the addition of the externally generated aerosol did produce signal enhancements, but the effect is believed to be unrelated to analyte transport and instead dependent upon changes in bulk properties of the plasma.