METHOD AND APPARATUS TO IMPROVE THE SEPARATION CAPACITY IN A SEQUENCE OF ION FILTERS INCORPORATING AT LEAST TWO ION MOBILITY ANALYZERS

摘要

A method and an apparatus are described to improve the separation capacity of an ion analyzer incorporating at least two stages of ion mobility analysis. The new invention utilizes possible use of different mixtures of gases and dopants in each stage, control over different concentrations of gases and dopants in each stage, and allowance of passage of the selected ions from one stage to the next while avoiding the mixing of the gases and dopants among stages. The new invention also includes a method to reduce the time required to identify the physical properties in a set of ion filters where at least one of the filters is a scannable ion mobility analyzer. The present invention also includes how to provide a set of scannable ion mobility analyzers operating in series, wherein each stage can be operated as a filter, or allowing for the passage of all ions.

主权项

1. An apparatus to separate ions simultaneously in different mixtures of gases and dopants with an enhanced separation capacity and with an improved transmission of ions, said apparatus comprising at least two ion mobility analyzers, each of said ion mobility analyzers having an inlet of ions and an outlet of ions,
wherein at least one among said two ion mobility analyzers is a scannable filter of the type: a Field Asymmetric Ion Mobility Spectrometer (FAIMS), a Differential Mobility Analyzer (DMA), or a Variable Electric Field Mobility Analyzer (VEFMA), for which said inlet of ions and said outlet of ions is a orifice or an slit, wherein said ion mobility analyzers are arranged in a linear sequence, having at least a first ion mobility analyzer, which receives a plurality of ions through a first inlet, and a last ion mobility analyzer which outputs a flow of selected ions through a last outlet, wherein said outlet of ions of said ion mobility analyzers, excluding said last ion mobility analyzer, serves at the same time as an inlet for the next ion mobility analyzer, and wherein ions classified in one stage are passed to a next for further classification, wherein a different mixture of gasses and dopants, which produce different shifts in the mobilities of each type of said ions, is introduced in each of said last ion mobility analyzers through a secondary inlet in each analyzer, wherein said plurality of ions is consecutively classified in said sequence of ion mobility analyzers.