A tubular membrane sampling device in an online mass spectrometer ionization source

Abstract

The invention designs a tubular membrane sampling device in an on-line mass spectrometer ionization source, which comprises: a tubular membrane, a heating lamp, a sampling metal tube, a particle filter net and an emergency shut-off electromagnetic valve. The tubular membrane is a non-porous dense polydimethylsiloxane tubular membrane. In the device, the tubular membrane is directly placed in the ionization zone; a heating lamp is placed outside the membrane as a membrane heating device; both ends of the membrane are connected with metal capillaries as the sampling inlet and outlet. A pump is installed on the side wall of the ionization zone cavity, and the pump port has an adjustable valve to adjust the vacuum degree of the ionization zone; an array of tubular membranes can be used in the ionization zone to facilitate large-flow sampling; this device improves the penetration of samples in the membrane rate, and improve sample ionization efficiency.

Description

technical field [0001] The invention belongs to a mass spectrometry instrument, in particular to a device in which a tubular membrane is directly placed in an ionization region and a heating lamp is used to heat the surface of the membrane. The device can overcome the disadvantage of the large diffusion loss of the sample that is enriched first and then injected through a capillary tube by common membrane injection. Under the action of pressure difference inside and outside the membrane and heating, the tubular membrane sampling device in the ionization source allows the analysis sample to quickly pass through the membrane and be directly ionized by the ionization source on the surface of the membrane. The device improves the permeation rate of the sample in the membrane and the ionization efficiency of the sample. Background technique [0002] Membrane sampling is widely used as a mass spectrometry sampling device. The membrane mainly plays the role of separating, enrichi...

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Problems solved by technology

[0003] Ordinary sheet-shaped membrane sampling device, due to the need to ensure the vacuum degree of the mass spectrometer, the area of ​​the sheet-shaped membrane is required to be small enough, resulting in a small injection volume of the analysis sample, and the sheet-shaped membrane is thin and easy to break

However, the ordinary tubular membrane sampling device has a thick membrane wall, and the response time of the analysis sample on the membrane is relatively long, resulting in a serious memory effect of the analysis sample on the membrane, so it is not conducive to the rapid online detection of environmental samples.

In addition, the analysis sample is enriched through the membrane and then injected through the capillary. During this process, the analysis sample will have a part of the diffusion loss, which will affect the analysis results.

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