Device for performing field asymmetric waveform ion mobility spectrometry

• Main Authors: Roch Andrzejewski, Roger Giles
• Format: Patent
• Language: English
• Published: 10.03.2021
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

A FAIMS device has segmented planar electrodes 820. Voltage waveforms are applied such that the asymmetric time dependent electric field has (near) straight electric field contour lines within the analytical gap, when viewed in a plane perpendicular to the analytical axis. This corresponds to establishing a linear gradient electric field across the gap. The straight/ linear contours may be achieved by using the segmented electrodes to emulate (Figs. 10C-D) the field due to truncated concentric cylindrical electrodes (Fig. 10B). This electric field focuses ions along the contour lines. Each ion species having a distinct differential mobility is focused on a distinct electric field contour line. The gradient may be adjusted to control the amount of focus. The length of the straight contours may be at least a quarter of the gap width. May have a transparent mode, exit slit and may be coupled to a mass spectrometer.