Ion mobility spectrometer migration region with enhanced ion focusing effect

Abstract

The invention provides an ion mobility spectrometer migration region with an enhanced ion focusing effect. The region comprises a migration region inner electrode which is a metal cylinder and is connected with a radio frequency power supply; a migration region outer electrode which is a metal hollow cylindrical column body, is connected with a ground electrode, is sleeved outside the migration region inner electrode, and is provided with a comb-shaped structure in the middle of the cylindrical column body along the axial direction, and gaps of the comb-shaped structure being disconnected at intervals; and an insulating spacer of an annular structure of which the shape is consistent with that of the broken gap of the comb-shaped structure, and arranged in the comb-shaped structure, so thatthe shape of the cylinder wall of the migration region outer electrode is kept complete. The outer electrode of the migration region is designed into the comb-shaped electrode, and compared with a traditional cylindrical migration region, the non-uniformity degree of an electric field in the gas flow channel is further increased, so that the migration region has a more obvious ion focusing effect. The insulating spacer is additionally arranged between the two metal electrode plates of the comb-shaped electrode, so that the surface area of the metal electrode is reduced, the ion loss is further reduced, and better signal quality can be obtained.

Description

technical field [0001] The invention relates to the field of ion migration, in particular to a migration region of an ion mobility spectrometer which adopts a cylindrical migration region with a grid electrode structure to enhance ion focusing effect. Background technique [0002] The migration region in the high-field asymmetric waveform ion migration region mostly adopts a flat plate structure or a cylindrical structure. Among them, the cylindrical transition region is widely used because of its ion focusing characteristics. [0003] However, although the cylindrical transition zone has the characteristics of ion focusing, compared with the flat transition zone, the ion signal of the large-gap cylindrical transition zone is weaker, because the gas channel gap and the volume of the cylindrical transition zone Larger, the volume flow rate of the gas is smaller than the gas volume flow rate in the plate-type migration zone, so that when the ions move forward with the carrier...

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Problems solved by technology

[0003] However, although the cylindrical transition zone has the characteristics of ion focusing, compared with the flat transition zone, the ion signal of the large-gap cylindrical transition zone is weaker, because the gas channel gap and the volume of the cylindrical transition zone Larger, the volume flow rate of the gas is smaller than the gas volume flow rate in the plate-type migration zone, so that when the ions move forward with the carrier gas and continue to diffuse, more ions will hit the electrode surface and be neutralized. Therefore, under the same gas flow rate, the ion loss in the cylindrical migration zone with a large gap is serious.

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