Q-Tof Mass Spectrometer

Invented a half-century ago by Nobel laureate Wolfgang Paul, the quadrupole mass filter has become an integral part of some of the most sophisticated mass spectrometers. Consisting of four parallel metal rods on which a fixed direct-current voltage and alternating radio-frequency voltage are applied, quadrupole mass filters allow users to selectively filter all ions except for those of a specified mass to charge ratio (m/z), depending on the applied voltage.