Plasma mass spectrum ion focusing deflection sample introduction interface and working mode

Abstract

The invention discloses a plasma mass spectrometry ion focusing deflection sample introduction interface and a working mode, and relates to an ion optical device. The interface comprises a plasma source for forming plasma through a gas ionization mode; a plurality of focusing deflection plates, wherein each focusing deflection plate is provided with a circular central channel, deflection electrode pairs are distributed on the edge of each circular central channel, and the plurality of focusing deflection plates are distributed between the plasma source and the mass spectrum sample introduction interface at a certain angle relative to the motion trail of the plasma. According to the invention, effective separation of photons and neutral particles and ion focusing are simultaneously realized in the ion transmission process.

Description

technical field [0001] The invention relates to an ion optical device, in particular to a plasma mass spectrometer ion focusing deflection sampling interface and a working mode. Background technique [0002] The sampling interface of the plasma mass spectrometer refers to the device that connects the plasma source and the mass spectrometer detector, and controls the target ion that is excited and ionized from the matrix to enter the mass spectrometer detector inlet. The ion sampling interface is in the middle hub between the plasma source that excites the sample and the mass analyzer. Its importance is to efficiently transmit the sample ions generated by the plasma source to the mass analyzer, which is important for the ion detection sensitivity and detection limit performance. influences. During the excitation process of the sample by the plasma source, with the generation of ions, a large number of photons and neutral particles will be generated at the same time. One of t...

AI Technical Summary

Problems solved by technology

Commonly used ion transmission interfaces include photon baffle type, off-axis deflection type, and 90-degree deflection type, etc. The photon baffle type has the problems of large ion loss, low transmission efficiency and mass discrimination; in the off-axis deflection type transmission interface, the sample substrate directly It is difficult to clean and maintain the lens parts on the surface of the ion lens, and the photon baffle type and off-axis deflection type mostly use horizontally placed rectangular tubes. Due to the thermal diffusion effect of the rectangular tube and plasma, there is a temperature difference between the upper and lower ends, which affects the temperature of the sample. ionization efficiency

Vertically placing the rectangular tube can solve the problem of the temperature difference of the rectangular tube. The existing vertically placed instruments mostly use deflection electrodes plus ion lenses or ion funnels during ion introduction. Although this method improves the selectivity of ions, but due to The flight path is longer, and the number of target ions entering the mass spectrometer will be reduced, resulting in a decrease in detection sensitivity

In addition, the combination of the two methods increases the volume of key components, which is extremely sensitive to trace moisture in the aerosol, and cannot fully atomize the sample metal elements.

When the sample enters the mass spectrometer through the plasma flame, it mostly exists in the form of metal ion conjugates composed of sample elements and different anions or water molecules, which are reflected in the mass spectrum as multiple mass spectrum peaks with different mass numbers, causing interference to mass spectrometry detection , which also reduces the sensitivity of the sample

Images