University of Missouri-Columbia homepage    University of Missouri-Columbia
MURR Introduction to the nation's premier university research reactor MURR Research and Development--R&D at the nation's premier university research reactor MURR Education--training tomorrow's nuclear scientists, engineers and technicians MURR Products and Services--providing quality nuclear products and services to a global community MURR Operations--safe and reliable MURR Research Opportunities for MU faculty and students
quality elemental analytical services that respond to your needs...click here to return to Analytical Chemistry main page
neutron activation analysis, chemical analysis
ICP-MS — The Quadrupole Mass Analyzer
This analyzer consists of four cylindrical rods onto which is applied both RF and DC electric fields. The four rods are arranged such that they form two pairs, one pair in the X plane and one in the Y.

Quadrupole Schematic
quadrupole schematic


As ions enter the quadrupole, they begin to oscillate in both the X and Y planes. In such a system, the lower m/e ions will be destabilized in the quadrupole whenever the alternating (RF) component of the electric field exceeds the direct (DC) component. In this instance, the lower m/e ions will quickly be thrown out of the quadrupole and will not reach the detector. This mode of operation makes an effective low mass filter.

If the direct component exceeds the alternating component then the reverse is true. High m/e ions become unstable while lower m/e ions are stabilized by the presence of the alternating component. This makes an effective high mass filter.

In the quadrupole, the mass analyzer is created by connecting the two pairs of rods in such a way that the X plane acts as a low mass filter and the Y plane acts as a high mass filter. By carefully matching the two fields, only ions of a particular mass are able to resonate at the correct frequency and pass through the quadrupole at any point in time.

The quadrupole mass analyzer is a very fast and efficient system.

to "ICP-MS--The High-Resolution Mass Analyzer"
Detection Limits Request a Quote

back to The Mass Analyzer Intro forward to The High-Resolution Mass Analyzer

MURR Introduction to the nation's premier university research reactor MURR Research and Development--R&D at the nation's premier university research reactor MURR Education--training tomorrow's nuclear scientists, engineers and technicians MURR Products and Services--providing quality nuclear products and services to a global community MURR Center homepage MURR Center homepage MURR Operations--safe and reliable University of Missouri-Columbia homepage MURR Site Map


MURR Relicensing
The reactor is in the process of relicensing for another 20 years of nuclear-based research, education and medical and other applications. Check here for project updates.


Content Copyright © 2003-2008 The Curators of the University of Missouri
DMCA and other copyright information. All rights reserved.
An equal opportunity/ADA institution.
If you would like more information or experience difficulty with any of these pages,
please contact our web editor.
Last updated August 2008