More efficient ion transport for inductively coupled plasma mass spectrometry

摘要

A modification of the ion-lens system in an inductively coupled plasma mass spectrometer has been studied in an attempt to improve the ion transport efficiency. The modification consists of the placement of a metal rod down the axis of the lens-stack.The rod is suspended in place via a ceramic insulator inserted through the photon stop A negative potential is applied to the rod to help focus the positively charged ions into the quadrupole Pnor to the implementation of this modification, a simple model was developed to determine if the voltages required would be practical. The resulting simulated ion trajectories showed that focusing occurs with applied voltages on the order of -10 V, which was approximately the optimal voltage found experimentallyThe experimental data presented show that, with the modification, the limits of detection for 15 elements (m/z ranging from 24 through 238) improved by factors ranging from two to ten times over those of the unmodified instrument.