Inductively coupled plasma mass spectrometry with an electrically floating sampling interface.

In conventional inductively coupled plasma mass spectrometry devices, the sampler and skimmer are grounded. In this work, modest DC voltages (+ 10 to + 50 Vl are applied to either (or both) sampler and skimmer. Alternatively, the skimmer is biased, and the sampler is merely left floating. The latter arrangement improves sensitivity for Co(+) by sixfold, provides nearly the same molar sensitivity for CO(+), Rh(+), and Ho(+), and extends the upper end of the linear dynamic range to approximately 100 ppm. These changes to the interface do not affect the background perceptibly. The relationship between applied potential and the potential actually measured on the sampler and skimmer is also discussed.