Triple quadrupole mass spectrometer with capability to perform multiple mass analysis steps

A method of analyzing a substance, the method comprising:

• (1) ionizing the substance to form a stream of ions;
• (2) subjecting the ion stream to a first mass analysis, to select ions having a desired mass to charge ratio, as precursor ions;
• (3) introducing the precursor ions into a collision cell to promote fragmentation of the precursor ions, thereby to generate primary fragment ions;
• (4) in the collision cell, selecting primary fragment ions having a desired mass to charge ratio, and rejecting other ions by removing ions of a mass to charge ratio greater than the mass to charge ratio of the selected primary fragment ions and separately removing ions with a mass to charge ratio less than the mass to charge ratio of the selected primary fragment ion, the removal of the ions with mass to charge ratios higher and lower than the mass to charge ratio of the selected primary fragment ion being effected in either order;
• (5) causing the selected primary fragment ions to collide, to promote further fragmentation, generating secondary fragment ions;
• and
• (6) mass analyzing the secondary fragment ions to generate a mass spectrum.

A method of analyzing a substance, the method comprising:

• (1) ionizing the substance to form a stream of ions;
• (2) subjecting the ion stream to a first mass analysis, to select ions having a desired mass to charge ratio, as precursor ions;
• (3) accelerating the precursor ions together with a collision gas into a low pressure section, to promote fragmentation of the precursor ions, thereby to generate primary fragment ions;
• and
• (4) subjecting the fragment ions to a second mass analysis, to generate a mass spectrum.