The effects of analyte mass and collision gases on ion beam formation in an inductively coupled plasma mass spectrometer

Planar laser induced fluorescence (PLIF) was used to evaluate the effect of matrix components on the formation and focusing of a Ba ion beam in a commercial inductively coupled plasma mass spectrometer. Cross sections of the ion beams were taken in the second vacuum stage, in front of the entrance to the mass analyzer. Under normal operating conditions, the addition of Pb shifted the position of the Ba ion beam to the right. PLIF was also used to evaluate the effect of a collision reaction interface (CRI) on Ca and Ba ion beams. A wider velocity distribution of ions and a decrease in overall intensity were observed for the CRI images. The fluorescence and mass spectrometer signals decreased with increased CRI flow rates. These effects were most obvious for Ca ions with He gas. - Highlights: • Planar laser induced fluorescence imaging is used to view ions in a working ICP-MS. • A Pb matrix shifts the position of Ba ions in a Varian 820 ICP-MS. • CRI increases the ion velocity distribution and decreases signal intensities.