Attenuation of matrix effects in inductively coupled plasma mass spectrometry with a supplemental electron source inside the skimmer

Electrons are added from a heated filament at the base of the skimmer to reduce the space charge repulsion in the ion beam. This technique improves the analyte sensitivity moderately and also minimizes the matrix effects caused by other elements in the sample significantly. The suppression of signal for even the most troublesome combination of light analyte and heavy matrix elements can be attenuated from 90 to 99% to only 2-10% for 2 mM matrix solutions with an ultrasonic nebulizer. The supplemental electron current can be adjusted to "titrate" out the matrix effects as desired.