The analyte ions enter the high vacuum area of the mass spectrometer and are drawn into a small hexapole with rf voltage only applied. With rf voltage only and no dc voltage applied, no ions are filtered. Therefore, all ions enter the first quadrupole. The quadrupole functions exactly as it did in the GC/MS. The operator can select the ions they wish to exit the first quadrupole. The selected ions are drawn into a component known as the collision cell. The collision gas, either nitrogen or argon, is introduced into the collision cell. As the selected ions enter the collision cell they collide with atoms of collision gas and fragment. The ion fragments are directed into the second quadrupole where the operator has selected the fragments desired to exit the second quadrupole and impact the electron multiplier.