Daughter ion spectra with time-of-flight mass spectrometers

US6300627A · kind A · utility

Assignee

• Bruker Daltonik GmbH · DE

Inventors

• Claus Koster · Lilienthal, DE
• Armin Holle · Oyten, DE
• Jochen Franzen · Bremen, DE

Key dates

• Filing date: Dec 1, 1999
• Grant date: Oct 9, 2001
• Expiry date: Dec 1, 2019

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J49/40
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

The invention relates to time-of-flight mass spectrometers for the measurement of daughter ion spectra (also called fragment ion spectra or MS/MS spectra) and corresponding measurement methods. According to the invention, the ions of an ion source are initially accelerated only to an intermediate level of energy, allowing them to decompose at that energy level by metastable decomposition or by collisionally induced fragmentation (CID). The ions are then accelerated in a second step to a high energy level. Light fragment ions gain a higher velocity than heavier fragment ions or non-decomposed parent ions. The spectrum of fragment ions can be detected separated by mass in either linear or reflector mode. An ion selector at the low energy level selects a single type of parent ion in order to avoid superpositions with fragment ions of other parent ions. A particularly preferred embodiment raises the potential of ions, for there second acceleration, during their flight through a small electrically isolated flight path chamber.