Ion Mobility Separation Using Mass-Filter Timing Windows
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Solution Overview
Problem
Conventional ion mobility separators (IMS) require ions to be trapped and pulsed into the separation region, which limits the scalability and complexity of experiments.
Innovation Solution
The instrument uses a mass filter or other selective transmission device to define the start time of the ion mobility separation cycle without axial trapping, allowing ions to be transmitted with varying physicochemical properties at different times, enhancing the timescales and complexity of experiments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ions are trapped and pulsed into the ion mobility separation region, then the ion mobility separation can be performed, but the scalability and complexity of experiments are limited
Solution Approach 1:
The invention extracts the ion trapping function from the ion mobility separator by using a separate mass filter device positioned upstream. This allows the ion mobility separator to focus solely on separation while the mass filter handles ion selection and timing, thereby increasing experimental complexity without adding device complexity in the mobility separator itself.
Solution Approach 2:
The mass filter device performs preliminary ion selection and defines the start time of the ion mobility separation cycle before ions enter the separation region. By pre-defining which ions to transmit and when, the system enables more complex experimental designs without requiring complex trapping mechanisms in the mobility separator.
2Measurement precision
If a mass filter is provided upstream of the ion mobility separator, then ions can be selected by mass to charge ratio, but the ions must still be trapped downstream of the mass filter which adds complexity
Solution Approach 1:
The invention merges the ion selection function of the mass filter with the timing control of ion mobility separation. The mass filter's transmission windows are used to define both which ions are selected and when they enter the mobility separator, eliminating the need for separate trapping arrangements and reducing overall device complexity.
Solution Approach 2:
The mass filter device performs multiple functions: it selects ions by mass to charge ratio, controls the timing of ion entry into the mobility separator, and defines the start time of the separation cycle. This multi-functionality eliminates the need for dedicated trapping mechanisms, reducing device complexity while maintaining precise mass selection.
3Loss of time
If ions are axially trapped between the mass filter and ion mobility separator, then the separation cycle can be defined, but the timescales are limited
Solution Approach 1:
The invention eliminates axial trapping to enable continuous ion transmission from the mass filter directly into the ion mobility separator. The mass filter's transmission windows continuously define which ions enter the separator and when, allowing for faster separation cycles and improved timescales without compromising ease of operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the scalability and complexity of ion mobility separation by defining the start time of the separation cycle based on physicochemical properties, enabling more selective analysis and simultaneous separation based on both properties and mobility.
Implementation Method 1
the mass filter may be a resolving quadrupole rod set mass filter to which RF and DC voltages are applied such that only ions having a mass to charge ratio, or ratios, within the window are able to be onwardly transmitted
Implementation Method 2
These ions are then pulsed into the separation region and are driven through a background gas arranged therein, such that the ions separate according to their mobilities through the background gas. The ions may be driven through the background gas by a static DC potential gradient
Implementation Method 3
Alternatively, the mass filter may be a notched mass filter to which a broadband AC frequency waveform is applied so as to eject all ions other than those that oscillate at a frequency corresponding to one or more notched portion of the broadband frequency waveform
Data Source
AI summary
An instrument for analysing ions is disclosed comprising: a first device (4) configured to onwardly transmit ions having a restricted range of physicochemical property values at any given time, and to change said range with time such that the first device (4) is capable of transmitting ions having different physicochemical property values at different times; and an ion mobility separator (6) arranged to receive ions transmitted by the first device (4); wherein the instrument is configured such that the time that any given ion enters the ion mobility separator (6) and begins to be separated from other ions is defined by its time of transmission by the first device.