Ultra-long coiled channel ion mobility spectrometry apparatus

Abstract

In some examples, an ion mobility spectrometry apparatus may include a plurality of printed circuit boards (PCBs). Each PCB of the plurality of PCBs may include a cutout. A plurality of electrodes may be disposed within at least a portion of the cutout for each PCB of the plurality of PCBs. Further, the plurality of PCBs may be stacked such that the plurality of electrodes are arranged to define an ion channel.

Description

20240128-02ULTRA-LONG COILED CHANNEL ION MOBILITY SPECTROMETRY APPARATUSCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to U. S. Provisional Patent Application Serial Number 63 / 736,297, filed December 19, 2024, titled “ULTRA-LONG COILED CHANNEL ION MOBILITY SPECTROMETRY APPARATUS”, which is incorporated by reference in its entirety.BACKGROUND

[0002] With respect to ion mobility spectrometry, and more specifically hybrid ion mobility-mass spectrometry instrumentation, ion mobility spectroscopy (IMS) may be utilized as an analytical tool in chemical sample analysis and analyte three-dimensional structure determination. Ion mobility spectrometry may be described as a gas phase separation technique where analyte ions are transported through either a static or constant flow buffer gas medium, such as nitrogen, helium, argon, or mixtures thereof. Furthermore, ion transport through these devices is based on either a static direct-current (DC) electric field or a dynamically modulated electric field. The ion separation may be based on the interaction of ions with a buffer gas. For example, small ions have a relatively smaller collision cross section and move through the buffer gas faster compared to larger ions with larger collision cross sections experiencing higher number of collisions and thereby resulting in a higher drag force and slower ion movement.20240128-02 BRIEF DESCRIPTION OF DRAWINGS

[0003] Features of the present disclosure are illustrated by way of example and not limited in the following figure(s), in which like numerals indicate like elements, in which:

[0004] Figure 1 illustrates a cross-sectional view through a channel in a linear path design for an ultra-long coiled channel ion mobility spectrometry apparatus (coiled channel ion mobility spectrometry apparatus) in accordance with an example of the present disclosure;

[0005] Figure 2 illustrates a three-dimensional (3D) diagram for a single printed circuit board (PCB) to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0006] Figure 3 illustrates a front side and a back side of a single PCB to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0007] Figures 4A-4D illustrate enlarged views of a front side and a back side of the single PCB of Figure 3 including application of different types of electric fields to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0008] Figure 5 illustrates a 3D diagram for a linear channel using PCB electrodes to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0009] Figure 6 illustrates a schematic diagram of electrode alignment between PCBs and a scheme of voltage application to create a dynamically modulated DC electric field20240128-02 to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0010] Figure 7 illustrates an isometric back side view of a single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) and a PCB stack for a coiled channel design to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0011] Figure 8 illustrates a front side view and a back side view of the single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) of Figure 7 to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0012] Figure 9 illustrates an enlarged back side view of the single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) of Figure 7 to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0013] Figure 10 illustrates a diagram of a coiled channel design in a single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) and a PCB stacked assembly to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0014] Figure 11 illustrates a cross-sectional and transparent views of a 3D diagram20240128-02 for a coiled channel to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0015] Figure 12 illustrates a diagram of a dual coiled channel design of a single PCB with dual electrode arrays and a PCB stacked assembly to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0016] Figure 13 illustrates a cross-sectional and transparent views of a 3D diagram of a dual coiled channel to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure;

[0017] Figures 14A-14B illustrate field strength and related diagrams of a PCB to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure; and

[0018] Figures 15A-15B illustrate variations in effective potential based on application of a dynamically modulated electric field to the examples of Figures 14A-14B to illustrate operation of the coiled channel ion mobility spectrometry apparatus of Figure 1, in accordance with an example of the present disclosure.20240128-02 DETAILED DESCRIPTION

[0019] For simplicity and illustrative purposes, the present disclosure is described by referring mainly to examples. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be readily apparent however, that the present disclosure may be practiced without limitation to these specific details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure the present disclosure.

[0020] Throughout the present disclosure, the terms "a" and "an" are intended to denote at least one of a particular element. As used herein, the term "includes" means includes but not limited to, the term "including" means including but not limited to. The term "based on" means based at least in part on.

[0021] An ultra-long coiled channel ion mobility spectrometry apparatus (hereinafter “coiled channel ion mobility spectrometry apparatus”) is disclosed herein. The term ultra-long as disclosed herein may refer to a coiled channel ion mobility spectrometry apparatus that provides extended ion trajectories within a comparable instrument footprint, enabling very high-resolution ion mobility separation. Also disclosed herein are a method of constructing an ultra-long ion mobility channel and a method of moving ions through this ultra-long ion mobility channel to achieve very high-resolution ion mobility separation. For the coiled channel ion mobility spectrometry apparatus disclosed herein, a coiled ion channel may be created in three-dimensional space, thus allowing a longer ion channel in a relatively smaller space.

[0022] With respect to ion mobility spectrometry, resolving power for ion mobility spectrometry based on either low field DC electric potential or dynamically modulated20240128-02 electric field ion manipulation may depend on channel length for separation. In this regard, resolving power is proportional to √L, where L is the channel length of the ion mobility separation. Thus, significantly longer separation paths may be needed to achieve higher resolving power ion mobility separations.

[0023] With respect to ion mobility techniques where static buffer gas is used, the resolving power is directly proportional to the length of the separation device, electric field used, and the charge state of the ion, and inversely proportional to the temperature of the buffer gas. Thus, in order to obtain higher resolving powers, one solution may be to increase the length of the separation device. With respect to instrument platforms that provide extended channel lengths and high ion mobility separation powers, such devices may utilize a travelling wave electric field for ion transportation through an ion mobility device and the separation may occur in a two-dimensional planar space or three-dimensional space.

[0024] In order to address technical challenges associated with ion mobility devices where separation may occur in a two-dimensional planar space, according to examples disclosed herein, the coiled channel ion mobility spectrometry apparatus disclosed herein provides an ultra-long ion channel in a coiled channel format to improve the utilization of three-dimensional space.

[0025] According to examples disclosed herein, a method for operating the coiled channel ion mobility spectrometry apparatus disclosed herein provides for transmitting ions through the ultra-long ion channel. An ion transmission direction may be different from the propagation direction of a dynamically modulated DC field as disclosed herein.

[0026] According to examples disclosed herein, a method of constructing ion channels20240128-02 disclosed herein provides for the creation of either linear or coiled ion channels. The linear channel design may be used to combine two or more coiled ion channels.

[0027] According to examples disclosed herein, a method of constructing a coiled channel may utilize printed circuit boards (PCBs). In particular, a cutout may be formed in each PCB along a curved or straight path, and electrodes may be patterned along the edges of the cutout and / or on the PCB surface. Multiple PCBs may then be stacked, for example, with controlled angular rotation between adjacent PCBs, to define a three- dimensional ion channel when assembled.

[0028] According to examples disclosed herein, a method of transporting ions through a coiled channel may utilize a combination of dynamically modulated DC electric field and radio frequency (RF) potential confinement. The RF and DC waveforms may be selected to provide stable ion trajectories for a mass-to-charge range of interest.

[0029] According to examples disclosed herein, an ion mobility spectrometry apparatus may include a plurality of printed circuit boards (PCBs). Each PCB of the plurality of PCBs may include a cutout. A plurality of electrodes may be disposed within at least a portion of the cutout for each PCB of the plurality of PCBs. Further, the plurality of PCBs may be stacked such that the plurality of electrodes are arranged to define an ion channel. In this regard, PCBs may be stacked with or without spacers between them and oriented parallel to each other.

[0030] According to examples of the ion mobility spectrometry apparatus disclosed herein, the ion channel may include a linear ion channel. A linear ion channel may be formed when the cutouts in the PCBs follow a straight path and the PCBs are not rotated with respect to one another. In such a configuration, the apparatus can be operated, for20240128-02 example, as a drift or travelling wave linear ion mobility separator or as an ion guide.

[0031] According to examples of the ion mobility spectrometry apparatus disclosed herein, the ion channel may include a coiled ion channel. A coiled ion channel may be formed when the cutouts in the PCBs follow an arc shape and the PCBs are rotated by a fixed or variable angle relative to one another. The resulting three-dimensional path may provide one or more full turns around a central axis, thereby extending the effective ion path length within a compact volume.

[0032] According to examples of the ion mobility spectrometry apparatus disclosed herein, the cutout for each PCB of the plurality of PCBs may be disposed at a different linear position relative to an adjacent PCB of the plurality of PCBs. For example, a cutout in one PCB may be shifted by a distance corresponding to one or more electrode blocks relative to the cutout in an adjacent PCB, such that electrode blocks are staggered or aligned in a manner that produces a continuous dynamically modulated DC field pattern along the ion channel.

[0033] According to examples of the ion mobility spectrometry apparatus disclosed herein, the cutout for each PCB of the plurality of PCBs may be disposed at a different angular position relative to an adjacent PCB of the plurality of PCBs. In one example, each PCB may be rotated by an angular increment such as 6°, 8°, 10°, 12°, or another suitable angle relative to the preceding PCB. The resulting angular offsets may combine to produce a helical channel geometry when a sufficient number of PCBs are stacked together. The angular offset may be selected based on factors such as desired channel pitch, total channel length, electrode density, RF confinement requirements, or available system footprint. In other examples, the angular displacement between PCBs may be20240128-02 non-uniform, allowing tailored ion path curvature or variable channel pitch profiles along the ion trajectory.

[0034] According to examples of the ion mobility spectrometry apparatus disclosed herein, the plurality of electrodes may include dynamically modulated DC electric field electrodes and radio-frequency (RF) electrodes. The combination of these electrodes may provide both axial ion transport and radial confinement.

[0035] According to examples of the ion mobility spectrometry apparatus disclosed herein, the ion channel may include RF electrodes, for example, to define boundaries of the ion channel.

[0036] According to examples of the ion mobility spectrometry apparatus disclosed herein, an ion entrance and an ion exit may be disposed on a same side of the plurality of stacked PCBs, for example, to form dual ion channels.

[0037] According to examples of the ion mobility spectrometry apparatus disclosed herein, an ion entrance and an ion exit may be disposed on different sides of the plurality of stacked PCBs, for example, to form a single ion channel.

[0038] According to examples of the ion mobility spectrometry apparatus disclosed herein, the plurality of PCBs forms an ion guide including a linear geometry.

[0039] According to examples of the ion mobility spectrometry apparatus disclosed herein, the plurality of PCBs forms an ion guide including a coiled geometry.

[0040] According to examples disclosed herein, an ion mobility spectrometry apparatus may include a plurality of PCBs. Each PCB of the plurality of PCBs may include at least one cutout. A plurality of electrodes may be disposed in at least a portion of the20240128-02 at least one cutout for each PCB of the plurality of PCBs. Further, the plurality of PCBs may be stacked to arrange the plurality of electrodes to define at least one ion channel.

[0041] According to examples of the ion mobility spectrometry apparatus disclosed herein, the at least one ion channel may include at least one linear ion channel.

[0042] According to examples of the ion mobility spectrometry apparatus disclosed herein, the at least one ion channel may include at least one coiled ion channel.

[0043] According to examples of the ion mobility spectrometry apparatus disclosed herein, the at least one ion channel may include two coiled ion channels. In this regard, the two coiled ion channels may be joined by a linear ion channel.

[0044] According to examples of the ion mobility spectrometry apparatus disclosed herein, an ion mobility spectrometry apparatus may include a plurality of PCBs. Each PCB of the plurality of PCBs may include at least one cutout. At least one electrode block may be disposed in at least a portion of the at least one cutout for each PCB of the plurality of PCBs. Further, the plurality of PCBs may be stacked to arrange the at least one electrode block to define at least one ion channel.

[0045] According to examples of the ion mobility spectrometry apparatus disclosed herein, the apparatus may be operated with dynamically modulated DC voltage or static DC voltage (e.g., constant DC electric field).

[0046] According to examples of the ion mobility spectrometry apparatus disclosed herein, the apparatus may be operated as an ion guide (e.g., without ion mobility separation).

[0047] With respect to operating pressures for the ion mobility spectrometry20240128-02 apparatus, when operated as an ion mobility separator, the operating pressures may be 10 millitorr to 1000 torr. When operated as an ion guide, the operating pressures may be 0.01 millitorr to 1000 torr.

[0048] With respect to RF electric field conditions for the ion mobility spectrometry apparatus, examples of RF electric field frequency may be 100 Hz to 100 MHz, and RF electric field amplitude may be 1-10000 V peak-to-peak.

[0049] With respect to dynamically modulated DC field information, frequency and amplitude for the ion mobility spectrometry apparatus, examples of DC electric potential used may be 0-1000 V and the speed of the DC modulation may be 10 m / s to 10000 m / s.

[0050] Figure 1 illustrates a cross-sectional view through a channel in a linear channel design for an ultra-long coiled channel ion mobility spectrometry apparatus (hereinafter “coiled channel ion mobility spectrometry apparatus 100”) in accordance with an example of the present disclosure.

[0051] Referring to Figure 1, the coiled channel ion mobility spectrometry apparatus 100 may be constructed using printed circuit boards (PCBs). A schematic diagram of a linear ion channel 102 is shown as being constructed using stacked PCBs, where a plurality of PCBs 104 are shown. In one example, each PCB and / or electrodes as disclosed herein may be individually addressable, enabling fine control over local electric potential. In other examples, groups of PCBs and / or electrodes may be addressed in blocks to reduce wiring complexity and signal routing specifications.

[0052] Figure 2 illustrates a three-dimensional (3D) diagram for a single PCB 200 to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in20240128-02 accordance with an example of the present disclosure.

[0053] Referring to Figure 2, along the axis of a PCB 200, electrodes 202 may be placed inside the cut-out edge on both top and bottom surfaces. These electrodes may be part of either a dynamically modulated DC electric field network, RF confining field network or a combined dynamically modulated DC electric field and RF field network. Electrode placement along the top and bottom surfaces may permit differential field shaping and symmetrical confinement.

[0054] Referring to Figures 1 and 2, and particularly to Figure 1, the direction of the wave propagation for dynamically modulated DC electric field is depicted by arrow 106, whereas the direction of ion motion is depicted by arrow 108. The dynamically modulated DC electric field propagation direction depicted by arrow 106 may thus form an angle relative to the ion motion direction depicted by arrow 108. Ions may travel from ion entrance 110 to ion exit 112. The ion channel 102 may be physically bounded by combined dynamically modulated DC electric field electrodes 114 and RF field electrodes 116 (superimposed RF fields on dynamically modulated DC electric field electrodes or separate dynamically modulated DC electric field and RF electrodes) on top and bottom surfaces, and RF field electrodes 116 in the horizontal axis (right and left side surfaces when viewed along the axis of the ion channel). Ion movement may be confined by both dynamically modulated DC electric field and RF fields. For the coiled channel Ion mobility spectrometry apparatus 100, transportation of ions along an axis that is at an angle to the principal dynamically modulated DC electric field propagation axis allows for the creation of a coiled channel in a three-dimensional space. In this regard, a coiled channel may be constructed using stacked PCBs as disclosed herein with respect to Figure 10-13.20240128-02

[0055] With reference to Figure 2, with respect to the PCB 200, in the example shown, the length, height, and width of the PCB may be 514 mm, 25 mm, and 1 mm, respectively. The cut-out dimension may be 36 mm long and 5 mm tall. Electrodes may be placed on the top and bottom edges of the cut-out region. The top and bottom electrodes may be connected to both a dynamically modulated DC electric field generator and an RF generator (not shown). As shown in the inset of cutout 208, each block 204 may represent a set of 8 electrodes (or an integer multiple of 8 electrodes). This 8-electrode unit may represent one complete dynamically modulated DC electric field waveform (e.g., as shown in Figure 4). In the example of Figure 2, the dimension of one electrode may be 1.5 mm x 1mm with 0.5 mm gap between electrodes along the PCB cut-out axis. Other electrode dimensions may be used depending on factors such as field gradient, ion mass range, and / or channel geometry.

[0056] An RF confining electrode 206 may be placed on the surface of the PCB at either side of the cut-out region. The RF confining electrodes may keep an ion beam at a center of the ion channel 102. In another embodiment, these surface electrodes may have both dynamically modulated DC electric field and RF confining electric field. In yet other embodiments, the RF electrodes may be patterned as segmented electrodes to provide spatially varying RF amplitudes along the ion channel 102.

[0057] With continued reference to Figures 1 and 2, electrode dimensions may vary. For example, in one example, a gap between electrodes may be 0.5 mm, an electrode length may be approximately 2 mm, and an electrode pitch may be approximately 2.5 mm.

[0058] Figure 3 illustrates a front side and a back side of a single PCB to illustrate20240128-02 operation of the apparatus 100, in accordance with an example of the present disclosure. The PCB may include mirrored electrode structures or distinct electrode patterns on opposing sides, enabling symmetric or asymmetric field configurations.

[0059] Referring to Figure 3, front side and back side views of a single PCB 300 are shown at 302 and 304, respectively. The front side 302 and the back side 304 may include electrically isolated routing layers connecting electrode pads to external connectors. These connectors may interface with one or more voltage drivers, arbitrary waveform generators, RF amplifiers, control electronics, or digital logic circuits configured to supply predetermined voltage sequences to the electrodes.

[0060] Figures 4A-4D illustrate enlarged views of a front side and a back side of the single PCB 300 of Figure 3 including application of different types of electric fields to illustrate operation of the apparatus 100, in accordance with an example of the present disclosure.

[0061] Referring to Figure 4A, the front side 302 and the back side 304 of the single PCB 300 show application of RF fields (positive and negative phases) applied to surface electrodes 400 and 406, respectively. Edge electrodes 402 may include both RF and dynamically modulated electric fields. Further, RF fields (positive and negative phases) may be applied at 404.

[0062] Referring to Figure 4B, the front side 302 and the back side 304 of the single PCB 300 show application of dynamically modulated electric and RF fields applied to surface electrodes 400 and 406, respectively. Edge electrodes 402 may include both RF and dynamically modulated electric fields. Further, RF fields (positive and negative phases) may be applied at 404.20240128-02

[0063] Referring to Figure 4C, the front side 302 and the back side 304 of the single PCB 300 show application of RF fields (negative phases) applied to surface electrodes 400 and 406, respectively. Edge electrodes 402 may include both RF and dynamically modulated electric fields. Further, RF fields (positive phase) may be applied at 404.

[0064] Referring to Figure 4D, the front side 302 and the back side 304 of the single PCB 300 show application of dynamically modulated electric and RF fields (negative phase) applied to surface electrodes 400 and 406, respectively. Edge electrodes 402 may include both RF and dynamically modulated electric fields. Further, RF fields (positive phase) may be applied at 404.

[0065] Figure 5 illustrates a 3D diagram for a linear channel using PCB electrodes to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in accordance with an example of the present disclosure.

[0066] Referring to Figure 5, a 3D diagram for a linear channel 500 using 83 PCB electrodes (cross-sectional view) is shown. The side walls 502 along the channel 500 may represent RF confining electrodes. For the example of Figure 5, the ion channel 500 may be created by sliding the adjacent PCB by one block of electrodes (e.g., 8 individual electrodes) such that electrode blocks align across all PCBs (e.g., see Figure 6). For the example of Figure 5, an 84 mm stack length may be used to create a 492 mm long ion channel 500. As shown at 504, a DC field may be applied to move ions into the channel 500.

[0067] Figure 6 illustrates a schematic diagram of electrode alignment between PCBs and a scheme of voltage application to create a dynamically modulated DC electric field to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in20240128-02 accordance with an example of the present disclosure.

[0068] Referring to Figure 6, an ion channel 600 may be created by sliding the adjacent PCB by one block of electrodes 602 (e.g., 8 individual electrodes) such that electrode blocks align across all PCBs. For example, a PCB with 48-electrode cutout may be shifted by 8 electrodes, or a 96-electrode cutout may be shifted by 16 electrodes. The blocks may represent electrodes that need to be aligned to generate a continuous dynamically modulated DC electric field along the entire channel. T = 0 shows where no voltage is applied to DC electrodes. T = 1 through T = 9 (skipping T = 2, 3, 5, 6 and 7 for simplicity) show which electrodes are activated to create the dynamically modulated DC field wave. For the example of Figure 6, dynamically modulated DC fields may include different shapes, such as sine wave, square wave, triangle wave, step wave, ramp, etc. Further, in one example, electrodes may be aligned with the same dynamically modulated DC field phase.

[0069] Figure 7 illustrates an isometric back side view of a single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) and a PCB stack for a coiled channel design to illustrate operation of the apparatus 100, in accordance with an example of the present disclosure.

[0070] Referring to Figure 7, an isometric back side view of a single PCB 700 and a PCB stack 702 for a coiled channel design are shown. The PCB stack 702 may be formed by repeating the PCB 700 multiple times, each with rotational or translational offsets, to define a coiled ion path. Signal routing elements may pass through or around the stack to provide electrical power and control voltages to each electrode group.

[0071] Figure 8 illustrates a front side view and a back side view of the single PCB20240128-02 700 with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) of Figure 7 to illustrate operation of the apparatus 100, in accordance with an example of the present disclosure.

[0072] Referring to Figures 7 and 8, and particularly Figure 8, a front side view 800 and a back side view 802 of the single PCB 700 are shown, for example, to illustrate the electrodes placed on the surface of the PCB.

[0073] Figure 9 illustrates an enlarged back side view of the single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) of Figure 7 to illustrate operation of the apparatus 100, in accordance with an example of the present disclosure (e.g., to illustrate the electrodes placed on the surface of the PCB and the electrodes placed on the inside edge of the cutout).

[0074] Referring to Figures 7 and 9, and particularly Figure 9, an enlarged back side view 900 of the single PCB 700 is shown. The enlarged view illustrates an example of electrode segment spacing.

[0075] Figure 10 illustrates a diagram of a coiled channel design in a single PCB with an electrode array (both edge electrodes inside the cutout and surface electrodes next to the cutout) and a PCB stacked assembly to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in accordance with an example of the present disclosure.

[0076] Referring to Figure 10, a diagram of a coiled channel design in a single PCB 1000 and a PCB stacked assembly 1002 (e.g., including 87 PCBs) are shown. For the example of Figure 10, a 72° cut-out may be used. Within this cutout, 96 edge electrodes20240128-02 are placed on both top and bottom edges. These 96 electrodes correspond to 12 blocks of 8 electrode units. Each 8-electrode unit corresponds to one block of dynamically modulated DC electric field electrodes. The coiled ion channel (e.g., see coiled ion channel 1100 of Figure 11) may be formed by adding the 87 PCBs, with each PCB being rotated 12° or by two blocks of 8-electrode units with respect to the preceding PCB. In the example of Figure 10, the cut-out inner diameter may be 300 mm, and the cut-out outer diameter may be 310 mm. The radius of the coiled ion channel 1100 may be 152.5 mm, and the length of the ion channel 1100 for one complete coil turn may be approximately 958 mm. Thus, for the example of Figure 10, 87 PCBs may be stacked to create a three-turn coiled ion channel 1100 resulting in an approximately 2875 mm long ion channel. In the example of Figure 10, each PCB may be estimated to be 1 mm thick, and the resulting PCB stack height may be 88 mm. The aforementioned dimensions are provided as an example only, and may be varied as needed. For example, instead of a 72° cut-out, a 36° cut-out may be used, with a 6° turn (e.g., PCB being rotated 6° with respect to the preceding PCB). In this regard, 60 PCBs may be utilized to complete one turn.

[0077] Figure 11 illustrates a cross-sectional and transparent views of a 3D diagram for the coiled ion channel 1100 to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in accordance with an example of the present disclosure.

[0078] Referring to Figure 11, a cross-sectional view 1102 and transparent views 1104 and 1106 of a 3D diagram for the coiled ion channel 1100 are illustrated. In this example, the distance between two adjacent ion channels is 29 mm. The aforementioned dimension is provided as an example only, and may be varied as needed. For example,20240128-02 instead of an 88 mm width and a 29 mm pitch as shown in Figure 10, the PCB stack may include a 184 mm width and a 60 mm pitch. Larger pitches may accommodate higher voltage operation, larger electrodes, or alternative channel geometries.

[0079] Figure 12 illustrates a diagram of a dual coiled channel design of a single PCB with dual electrode arrays and a PCB stacked assembly 1202 to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in accordance with an example of the present disclosure.

[0080] Referring to Figure 12, a dual coiled channel design of a single PCB 1200 and a PCB stacked assembly 1202 including 87 PCBs (e.g., 87 single PCBs with surface and edge electrode arrays) is illustrated. Each single PCB 1200 may include two 72° cut¬ outs. The coiled ion channel (e.g., coiled ion channel 1300 of Figure 13) may be constructed by adding 87 PCBs, with each PCB being rotated 12° with respect to the preceding PCB. In the example of Figure 12, an inner diameter of cutout 1204 is 300 mm, and an outer diameter of the cutout 1204 is 310 mm. In the example of Figure 12, a radius of the coiled ion channel 1300 is 152.5 mm and a length of the coiled ion channel 1300 for one turn is approximately 958 mm. Thus, for the example of Figure 12, 87 PCBs may be stacked to create two 3-turn coiled channels resulting in an approximately 5751 mm long combined ion channel (without accounting for the length of the connecting linear ion channel). The two coiled channels may be connected using a linear channel creating one long coiled ion channel. In the example of Figure 12, each PCB may be estimated to be 1 mm thick, with the resulting PCB stack height being 88 mm. The aforementioned dimensions are provided as an example only, and may be varied as needed.

[0081] Figure 13 illustrates a cross-sectional view 1302 and transparent views 130420240128-02 (cross-sectional) and 1306 of a 3D diagram of a dual coiled ion channel 1300 to illustrate operation of the coiled channel ion mobility spectrometry apparatus 100, in accordance with an example of the present disclosure.

[0082] Referring to Figure 13, for the coiled ion channel 1300, in one example, the distance between two adjacent ion channels (e.g., coil pitch) may be specified at 14 mm. For the example of Figure 13, the two coiled channels may be connected using a linear channel (e.g., the linear channel of Figure 1), thus creating one long ion channel. Furthermore, for the example of Figure 13, ion entrance 1308 and ion exit 1310 may be on the same side of the PCB stack (e.g., the PCB stacked assembly 1202). This may allow for the coupling of two or more PCB stacks to generate a combined design with different ion channel path lengths. The aforementioned dimensions for the coiled ion channel 1300 are provided as an example only, and may be varied as needed.

[0083] Figures 14A-14B illustrate field strength and related diagrams of a PCB to illustrate operation of the apparatus 100, in accordance with an example of the present disclosure.

[0084] Referring to Figure 14A, Figure 14A illustrates a first implementation 1400, including a front view 1402, a view along section A-A at 1404, and a field strength plot 1406. The first implementation 1400 corresponds to Figure 4C. The field strength plot 1406 shows a field strength of the dynamically modulated electric field. The field strength is strongest closest to the edge electrodes where the dynamically modulated electric field is applied.

[0085] Referring to Figure 14B, Figure 14B illustrates a second implementation 1420, including a front view 1422, a view along section A-A at 1424, and a field strength plot20240128-02 1426. The second implementation 1400 corresponds to Figure 4D. The field strength plot 1426 shows a field strength of the dynamically modulated electric field, and a uniform field strength.

[0086] Figures 15A-15B illustrate variations in effective potential based on application of a dynamically modulated electric field to the examples of Figures 14A-14B to illustrate operation of the apparatus 100, in accordance with an example of the present disclosure.

[0087] Referring to Figures 15A-15B, Figures 15A-15B illustrate variations 1500 and 1520 in effective potential based on application of a dynamically modulated electric field to the first through third implementations 1400 and 1420, respectively, of Figures 14A-14B. The effective potential at 1500 may represent a dynamically modulated electric field on side electrodes (top and bottom electrodes are RF) for the first implementation 1400. The effective potential perpendicular to the ion path at 1502 may represent a dynamically modulated electric field applied on all electrodes for the second implementation 1402. The effective potential at 1500 shows that when a dynamically modulated electric field is limited to application to side electrodes, this can lead to loss of ions. In this regard, for a given applied electric field strength, a finite effective potential depth (defined by the applied RF frequency and amplitude) may limit the mass range of a device, and for a given effective potential depth (defined by RF frequency and amplitude), the maximum applicable electric field strength may be limited, limiting the resolution of the device. The effective potential at 1502 shows that when a dynamically modulated electric field is applied to all electrodes compared to the effective potential at 1500, all of the lines of the graph at 1502 show a local minimum, which is preferred. In this regard, application of the electric field to all electrodes allows for application of field strengths that are large20240128-02 enough to perform high field asymmetric waveform ion mobility spectrometry (FAIMS) implemented as an asymmetric travelling waveform.

[0088] What has been described and illustrated herein is an example along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Many variations are possible within the spirit and scope of the subject matter, which is intended to be defined by the following claims - and their equivalents - in which all terms are meant in their broadest reasonable sense unless otherwise indicated.

Claims

20240128-02 What is claimed is:

1. An ion mobility spectrometry apparatus comprising:a plurality of printed circuit boards (PCBs), wherein each PCB of the plurality of PCBs includes a cutout; anda plurality of electrodes disposed within at least a portion of the cutout for each PCB of the plurality of PCBs,wherein the plurality of PCBs is stacked such that the plurality of electrodes are arranged to define an ion channel.

2. The ion mobility spectrometry apparatus according to claim 1, wherein the ion channel comprises a linear ion channel.

3. The ion mobility spectrometry apparatus according to claim 1, wherein the ion channel comprises a coiled ion channel.

4. The ion mobility spectrometry apparatus according to claim 1, wherein the cutout for each PCB of the plurality of PCBs is disposed at a different linear position relative to an adjacent PCB of the plurality of PCBs.

5. The ion mobility spectrometry apparatus according to claim 1, wherein the cutout for20240128-02 each PCB of the plurality of PCBs is disposed at a different angular position relative to an adjacent PCB of the plurality of PCBs.

6. The ion mobility spectrometry apparatus according to claim 1, wherein the plurality of electrodes includes dynamically modulated electric field electrodes and radiofrequency (RF) electrodes.

7. The ion mobility spectrometry apparatus according to claim 1, wherein the ion channel includes radiofrequency (RF) electrodes.

8. The ion mobility spectrometry apparatus according to claim 1, further comprising:an ion entrance and an ion exit on a same side of the plurality of stacked PCBs to form dual ion channels.

9. The ion mobility spectrometry apparatus according to claim 1, further comprising:an ion entrance and an ion exit on different sides of the plurality of stacked PCBs to form a single ion channel.

10. The ion mobility spectrometry apparatus according to claim 1, wherein the plurality of PCBs forms an ion guide comprising a linear geometry.20240128-02 11. The ion mobility spectrometry apparatus according to claim 1, wherein the plurality of PCBs forms an ion guide comprising a coiled geometry.

12. The ion mobility spectrometry apparatus according to claim 1, wherein the apparatus operates with dynamically modulated DC voltage or static DC voltage.

13. An ion mobility spectrometry apparatus comprising:a plurality of printed circuit boards (PCBs), wherein each PCB of the plurality of PCBs includes at least one cutout;a plurality of electrodes disposed in at least a portion of the at least one cutout for each PCB of the plurality of PCBs; anda plurality of further electrodes disposed on at least a portion of a surface of each PCB of the plurality of PCBs,wherein the plurality of PCBs is stacked to define at least one ion channel.

14. The ion mobility spectrometry apparatus according to claim 13, wherein the at least one ion channel includes at least one linear ion channel.

15. The ion mobility spectrometry apparatus according to claim 13, wherein the at least one ion channel includes at least one coiled ion channel.20240128-02 16. The ion mobility spectrometry apparatus according to claim 13, wherein the at least one ion channel includes two coiled ion channels.

17. The ion mobility spectrometry apparatus according to claim 16, wherein the two coiled ion channels are joined by a linear ion channel.

18. The ion mobility spectrometry apparatus according to claim 13, further comprising:an ion entrance and an ion exit on a same side of the plurality of stacked PCBs forming dual ion channels.

19. The ion mobility spectrometry apparatus according to claim 13, further comprising:an ion entrance and an ion exit on different sides of the plurality of stacked PCBs forming a single ion channel.

20. The ion mobility spectrometry apparatus according to claim 13,wherein the plurality of PCBs forms an ion guide comprising a linear geometry, or wherein the plurality of PCBs forms an ion guide comprising a coiled geometry.

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