Preparation of ion pulse for time-of-flight and for tandem time-of-flight mass analysis

A tandem time-of-flight mass spectrometer comprising:

• (a) a pulsed ion source;
• (b) a first time-of-flight mass spectrometer connected to the ion source for selecting pulses of precursor ions for further analysis;
• (c) a fragmentor in communication with the first time-of-flight mass spectrometer for receiving the pulses of precursor ions and dissociating at least a portion of the precursor ions into fragment ions;
• (d) an ion trap in communication with the fragmentor for receiving pulses of precursor and fragment ions;
• (e) a power supply coupled to the ion trap providing RF and DC voltages to the ion trap for dynamically trapping and confining the pulses of precursor and fragment ions;
• (f) a gas supply for regulating the pressure within the trap to produce collisional cooling of the precursor and fragment ions confined therein;
• (g) a source of pulsed voltages applied to the ion trap for extracting pulses of precursor and fragment ions from the trap;
• and
• (h) a second time-of-flight mass spectrometer receiving the extracted pulses of ions.

A tandem mass spectrometer utilizing the same time-of-flight analyzer for both precursor ion selection and analysis of fragment ions comprising:

• (a) an ion source having an accelerating chamber;
• (b) an annular detector mounted in the accelerating chamber with an inner hole through which accelerated ions pass;
• (c) an ion mirror receiving the ions and redirecting the ions out of the mirror;
• (d) a timed ion selector for selecting precursor ions from the ions generated by the ion source;
• (e) a fragmentor for dissociating and dynamically trapping the precursor ions in a quadrupolar field for a pre-selected trapping time;
• (f) means for accelerating ions out of the fragmentor slightly off angle to the direction from which they entered, the fragments and any remaining precursor ions being redirected toward the ion mirror, thereby to energy focus the ions and redirect them toward the surface of the detector.

A method of analysis by mass spectrometry comprising the steps of:

• (a) producing ion pulses;
• (b) confining the ion pulses in a segmented ion trap;
• (c) regulating the pressure of a gas supplied to the segmented ion trap to produce collisional cooling of the confined ions;
• and
• (d) directing the collisionally cooled ions from the segmented ion trap to a time-off-light mass analyzer.

A method of analysis by tandem mass spectrometry comprising the steps of:

• (a) using a first time-of-flight mass analyzer to select pulses of precursor ions;
• (b) fragmenting at least a portion of the precursor ions;
• (c) confining the pulsed precursor and fragmented ions in an ion trap;
• (d) regulating the pressure of a gas supplied to the ion trap to produce collisional cooling of the ions confined therein;
• and
• (e) directing the collisionally cooled ions from the ion trap to a second time-of-flight mass analyzer for further analysis.