Instrument, including an electrostatic linear ion trap, for analyzing ions

An instrument for analyzing ions, comprising:

• an ion source configured to generate ions from a sample,
• at least one ion processing instrument configured to receive the generated ions from the ion source and to process the generated ions by one or a combination of filtering the ions according to a molecular characteristic and dissociating the ions,
• an electrostatic linear ion trap (ELIT) positioned to receive ions exiting the at least one ion processing instrument and configured to trap at least one of the received ions therein, the ELIT including first and second ion mirrors and a charge detection cylinder positioned between the first and second ion mirrors, and
• at least one voltage source coupled to the first and second ion mirrors, the at least one voltage source configured to establish electric fields in each of the first and second ion mirrors configured to reflect the trapped at least one ion entering a respective one of the first and second ion mirrors from the charge detection cylinder back through the charge detection cylinder and into the other of the first and second ion mirrors such the trapped at least one ion oscillates back and forth between the first and second ion mirrors each time passing through the charge detection cylinder,
• wherein time spent by the trapped at least one ion passing through the charge detection cylinder is approximately equal to a sum of time spent by the trapped at least one ion travelling from a stopped position within one of the first and second ion mirrors into a respective end of the charge detection cylinder and time spent by the trapped at least one ion traveling from an opposite respective end of the charge detection cylinder to a stopped position within the other of the first and second ion mirrors.

A method for analyzing ions, comprising:

• generating ions from a sample,
• processing the generated ions by one of filtering the ions according to a molecular characteristic and dissociating the ions to produce first processed ions,
• processing the first processed ions by the other of filtering the ions according to the molecular characteristic and dissociating the ions to produce second processed ions, and
• analyzing the second processed ions with an electrostatic linear ion trap, having first and second ion mirrors and a charge detection cylinder positioned between the first and second ion mirrors, by (i) establishing a first electric field in the first ion mirror, the first electric field configured to stop in the first ion mirror at least one of the second processed ions exiting a first end of the charge detection cylinder, proximate to the first ion mirror, and traveling into the first ion mirror, and to accelerate the stopped at least one of the second processed ions in the first ion mirror back into the first end of the charge detection cylinder, and (ii) establishing a second electric field in the second ion mirror, the second electric field configured to stop in the second ion mirror the at least one of the second processed ions exiting a second end of the charge detection cylinder, proximate to the second ion mirror, and traveling into the second ion mirror, and to accelerate the stopped at least one of the second processed ions in the second ion mirror back into the second end of the charge detection cylinder, such that the at least one of the second processed ions oscillates back and forth between the first and second ion mirrors under the influence of the first and second electric fields each time passing through the charge detection cylinder,
• wherein time spent by the at least one of the second processed ions passing through the charge detection cylinder is approximately equal to a sum of time spent by the at least one of the second processed ions travelling from a stopped position within one of first and second ion passageways into a respective end of the charge detection cylinder and time spent by the at least one of the second processed ions traveling from an opposite respective end of the charge detection cylinder to a stopped position within the other of the first and second ion passageways.