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JP-2026075440-A - Ion interface, ion interface assembly, and plasma mass spectrometer

JP2026075440AJP 2026075440 AJP2026075440 AJP 2026075440AJP-2026075440-A

Abstract

[Problem] To reliably perform trace analysis of Fe, Ni, and Cr contained in a sample using a plasma mass spectrometer. [Solution] A plasma mass spectrometer comprising a plasma source that ionizes a sample with plasma to generate ions, an ion interface assembly that guides the ions generated by the plasma source, and an analysis unit that analyzes the ions guided by the ion interface assembly, wherein the ion interface assembly includes a low-impurity section 72 made of a metal having a total content of Fe, Ni, and Cr of 2% by mass or less. [Selection Diagram] Figure 4

Inventors

  • 二宮 香里
  • 飯田 雅直
  • 小松谷 俊介

Assignees

  • 日本電気硝子株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (17)

  1. An ion interface used in a plasma mass spectrometer, An ion interface characterized by having a low-impurity portion composed of metals with a total content of Fe, Ni, and Cr of 2% by mass or less.
  2. The ion interface according to claim 1, wherein the low-impurity portion is composed of titanium or a titanium alloy.
  3. The ion interface according to claim 1 or 2, wherein the ion interface is an ion lens.
  4. The ion interface according to claim 3, wherein the entire ion lens is composed of the low-impurity portion.
  5. The ion lens has a metal layer on the surface of the low-impurity portion, The ion interface according to claim 3, wherein the metal layer comprises a layer composed of elemental metals or alloys, including materials selected from cobalt, gold, silver, copper, tungsten, zinc, platinum, palladium, and tin.
  6. The ion interface according to claim 5, comprising: a first layer composed of a single metal or alloy containing a material selected from cobalt, gold, silver, copper, tungsten, zinc, platinum, palladium, and tin; and a second layer formed on the first layer and composed of a single metal or alloy containing a material selected from gold, silver, copper, tungsten, zinc, platinum, palladium, and tin, wherein the metal constituting the first layer is different from the metal constituting the second layer.
  7. The ion interface according to claim 6, wherein the total thickness of the metal layer is 1 to 200 μm.
  8. The ion interface according to claim 1 or 2, wherein the ion interface is a skimmer cone.
  9. The ion interface according to claim 8, wherein the entire skimmer cone is composed of the low-impurity portion.
  10. The skimmer cone has a metal layer on the surface of the low-impurity portion, The ion interface according to claim 9, wherein the metal layer comprises a layer composed of a single metal or alloy containing a material selected from gold, platinum, palladium, rhodium, and iridium.
  11. The ion interface according to claim 1 or 2, wherein the ion interface is a sampling cone.
  12. The central part of the sampling cone is the low-impurity portion, The ion interface according to claim 11, wherein the outer periphery of the sampling cone is a high thermal conductivity portion made of a metal having a higher thermal conductivity than the low impurity portion.
  13. The ion interface according to claim 12, wherein the thermal conductivity of the high thermal conductivity portion is 80 W/(m·K) or higher.
  14. The ion interface according to claim 12, wherein the high thermal conductivity portion is composed of a single metal or alloy containing a material selected from zinc, aluminum, gold, and silver.
  15. The sampling cone is provided with a metal layer on at least the surface of the low-impurity portion. The ion interface according to claim 11, wherein the metal layer comprises a layer composed of a single metal or alloy containing a material selected from gold, platinum, palladium, rhodium, and iridium.
  16. A plasma mass spectrometer comprising a plasma source that ionizes a sample with plasma to generate ions, an ion interface assembly that guides the ions generated by the plasma source, and an analysis unit that analyzes the ions guided by the ion interface assembly, A plasma mass spectrometer characterized in that the ion interface assembly comprises the ion interface described in claim 1 or 2.
  17. An ion interface assembly used in a plasma mass spectrometer, It comprises an ion lens, a skimmer cone, and a sampling cone. An ion interface assembly characterized in that each of the ion lens, the skimmer cone, and the sampling cone comprises a low-impurity portion composed of a metal with a total content of Fe, Ni, and Cr of 2% by mass or less.

Description

This invention relates to an ion interface, an ion interface assembly, and a plasma mass spectrometer. Plasma mass spectrometers such as inductively coupled plasma mass spectrometers (ICP-MS) and microwave plasma mass spectrometers (MIP-MS) can analyze inorganic elements, especially trace amounts of metals, with high precision (see, for example, Patent Document 1). This type of plasma mass spectrometer comprises a plasma source that ionizes a sample using plasma to generate ions, an ion interface that guides the ions generated by the plasma source, and an analysis unit that analyzes the ions guided by the ion interface. An ion interface assembly is composed of a combination of ion interfaces such as ion lenses, skimmer cones, and sampling cones. Japanese Patent Publication No. 2009-043608 This is a schematic diagram showing a plasma mass spectrometer according to an embodiment of the present invention.This is a front view showing the sampling cone.This is a front view showing the skimmer cone.This is a front view showing an ion lens.This is a cross-sectional view taken along line A-A in Figure 4. The embodiments for carrying out the present invention will be described below with reference to the drawings. (Plasma mass spectrometer) As shown in Figure 1, an inductively coupled plasma mass spectrometer (ICP-MS) is exemplified as the plasma mass spectrometer 1 according to this embodiment. The plasma mass spectrometer 1 comprises a plasma source 2, an ion interface assembly 3, and an analysis unit 4. Plasma source 2 ionizes sample X using plasma (e.g., argon plasma) and generates ions originating from sample X. Sample X is a liquid containing not only the analyte such as glass powder, but also an acid such as hydrofluoric acid for sample preparation, and is sprayed into the plasma. The plasma temperature is, for example, 5000°C to 10000°C. The ion interface assembly 3 guides ions generated by the plasma source 2 to the analysis unit 4. The ion interface assembly 3 is a combination of multiple ion interfaces, and in this embodiment, it comprises, in order from the plasma source 2 side, a sampling cone 5, a skimmer cone 6, and an ion lens 7. Ions generated by the plasma source 2 are rapidly drawn towards the ion lens 7 by the sampling cone 5 and skimmer cone 6. Ions that have passed through the sampling cone 5 and skimmer cone 6 are focused by the ion lens 7 and introduced into the analysis unit 4 (collision/reaction cell 8). In this process, the ion lens 7 separates ions from other particles such as photons. The analysis unit 4 analyzes ions induced by the ion interface assembly 3. The analysis unit 4 comprises a collision-reaction cell 8, a quadrupole mass filter 9 as a mass separation unit, and an ion detector 10. Ions focused by the ion lens 7 are introduced into the collision-reaction cell 8. Unwanted ions are removed in the collision-reaction cell 8. Ions primarily derived from the sample components pass through the collision-reaction cell 8 and are introduced into the quadrupole mass filter 9. Only ions with a specific mass-to-charge ratio selectively pass through the quadrupole mass filter 9 and are introduced into the ion detector 10. The ion detector 10 detects ions with the specific mass-to-charge ratio that have passed through the quadrupole mass filter 9. Next, the sampling cone 5, skimmer cone 6, and ion lens 7, which constitute the ion interface assembly 3, will be described in detail. (Sampling cone) As shown in Figure 2, the sampling cone 5 is substantially conical in shape and has an ion passage 51 at its apex. In this embodiment, the sampling cone 5 comprises a low-impurity section 52 located in the center and a high-thermal-conductivity section 53 located on the outer periphery. The ion passage 51 is located in the center of the low-impurity section 52. The low-impurity portion 52 is composed of a metal with a total content (Fe + Ni + Cr) of 2 mass% or less of Fe, Ni, and Cr. Preferably, the Fe + Ni + Cr content in the low-impurity portion 52 is 2 mass% or less, more preferably 0.5 mass% or less, and even more preferably 0.1 mass or less. This ensures that Fe, Ni, and Cr originating from the sampling cone 5 are reliably detected by the ion detector 10. The Fe, Ni, and Cr content in the low-impurity portion 52 can be measured using, for example, LA-ICP-MS, X-ray fluorescence analysis, GD-OES, LA-ICP-OES, etc. The Fe content in the low-impurity portion 52 is preferably 2% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. The Ni content in the low-impurity portion 52 is preferably 2% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. The Cr content in the low-impurity portion 52 is preferably 2% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. The low-impurity portion 52 is preferably composed of titanium or a titanium alloy. Titanium and tit