Methods and systems for providing a substantially quadrupole field with significant hexapole and octapole components

摘要

A system and method involving processing ions in a linear ion trap are provided, involving a two-dimensional asymmetric substantially quadrupole field having a hexapole and octopole component.

主权项

1. A method of processing ions in a linear ion trap, the method comprising:
establishing and maintaining a two-dimensional asymmetric substantially quadrupole field having a first axis, a first axis potential along the first axis, a second axis orthogonal to the first axis and a second axis potential along the second axis, wherein i) the first axis potential comprises a quadrupole harmonic of amplitude A21, a hexapole harmonic of amplitude A31 and an octapole harmonic of amplitude A41, A41 is greater than 0.01% of A21, A41 is less than 5% of A21 and 33% of A31, and for any other higher order harmonic with amplitude An1 present in the first axis potential, n1 being any integer greater than 4, A31 is greater than ten times An1; and, ii) the second axis potential comprises a quadrupole harmonic of amplitude A22, and an octapole harmonic of amplitude A42, wherein A42 is greater than 0.01% of A22, A42 is less than 5% of A22 and, for any other higher order harmonic with amplitude An2 present in the second axis potential of the field, n2 being any integer greater than 2 except 4, A42 is greater than ten times An2; introducing ions to the field.