Inductively coupled plasma mass spectrometry with ambient helium surrounding ion source

摘要

An enclosed device surrounding the argon inductively coupled plasma torch was fabricated to exclude air entrainment and attenuate background interferences. Helium was introduced into the enclosure, and ambient helium plasma was formed stably. Under cold plasma condition, we found that the spectral background decreased about 1 order of magnitude averagely compared with that in typical operation condition. For laser ablation with a Nd:YAG laser, the limits of detection of ~(28)Si,~(29)Si, ~(31)P, and ~(32)S in an iron matrix were improved significantly; the linearity of their calibration curves was greatly improved as well compared with standard mode and cool mode ICP-MS with no ambient helium. The result indicates that polyatomic interferences from nitrogen, oxygen, hydrogen, carbon, etc. were effectively reduced in helium ambient ICP-MS.