Diathermy knife ionisation source

Patent metadata

Field	Value
Publication number	US-9947524-B2
Application number	US-201514727941-A
Country	US
Kind code	B2
Filing date	Jun 2, 2015
Priority date	Jun 3, 2011
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A method of detecting one or more compounds, chemicals or contaminants in a substrate by mass spectrometry is disclosed. A non-living substrate is analyzed by contacting the substrate with a diathermy knife. An electric current is applied to the diathermy knife such that the diathermy knife vaporizes a portion of the substrate. The vapor is aspirated via a sampling tube pumped by a venturi pump into a vacuum chamber of a mass spectrometer. Analyte molecules are aspirated into the vacuum chamber whereupon they impact a surface of the vacuum chamber and are ionized to form analyte ions which are then mass analyzed.

First claim

The invention claimed is:

1. A non-surgical method of mass spectrometry comprising:
probing a substrate with an electrode, a jet of fluid, or a laser probe at atmospheric pressure to cause a portion of the substrate to vaporise to generate a plurality of gas-phase analyte molecules, wherein the substrate comprises a food product;
transporting at least a portion of the generated gas-phase analyte molecules into a vacuum chamber of a mass spectrometer, wherein a surface of the vacuum chamber is arranged for ionising analyte molecules;
causing at least a portion of the generated gas-phase analyte molecules to be ionized by impacting upon said surface of the vacuum chamber of the mass spectrometer to form analyte ions;
mass analysing at least a portion of the analyte ions; and
further comprising detecting if one or more contaminants are present in the substrate above a predetermined concentration.

2. A method as claimed in claim 1 , wherein the electrode comprises an electrode of a diathermy knife or an electrosurgical RF knife.

3. A method as claimed in claim 1 , further comprising aspirating the analyte molecules via a tube or supply line into the mass spectrometer.

4. A method as claimed in claim 1 , further comprising using a pump to draw the analyte molecules into the mass spectrometer, wherein the pump is not directly connected to an exhaust port of a vacuum chamber.

5. A method as claimed in claim 1 , wherein at least a portion of the analyte molecules are ionised upon impacting an RF ion-optical component located within the vacuum chamber.

6. A method as claimed in claim 1 , wherein a portion of the analyte molecules are ionised by an ion source located within the vacuum chamber.

7. A method as claimed in claim 1 , wherein the step of probing the substrate with the probe generates a mixture of analyte molecules and droplets, the method comprising:
transporting at least a portion of the mixture into the vacuum chamber of the mass spectrometer; and
mass analysing at least a portion of the analyte ions and the droplets or at least a portion of further analyte ions derived from the droplets.

8. A method as claimed in claim 1 , comprising using a portable mass spectrometer to perform the step of mass analysing at least a portion of the analyte ions.

9. A method as claimed in claim 1 , wherein the substrate comprises a solid, gel or powder.

10. A method as claimed in claim 1 , wherein said contaminant is selected from the group comprising: (i) a pesticide; (ii) a steroid; (iii) chloramphenicol; (iv) a bulking material; or (v) a mycotoxin.

11. A method as claimed in claim 1 , wherein said contaminant comprises histamine, putrescine or cadaverine.

12. A method as claimed in claim 1 , further comprising determining a freshness of the food product.

13. A method of mass spectrometry comprising:
probing a substrate with an electrode, a jet of fluid, or a laser probe at atmospheric pressure to cause a portion of the substrate to vaporise to generate a plurality of gas-phase analyte molecules;
transporting at least a portion of the generated gas-phase analyte molecules into a vacuum chamber of a mass spectrometer, wherein a surface of the vacuum chamber is arranged for ionising analyte molecules;
causing at least a portion of the generated gas-phase analyte molecules to be ionized by impacting upon said surface of the vacuum chamber of the mass spectrometer to form analyte ions; and
mass analysing at least a portion of the analyte ions.

14. A method as claimed in claim 13 , wherein the substrate comprises a food product, the method further comprising determining a freshness of the food product.

15. A non-surgical method of mass spectrometry comprising:
probing a substrate with an electrode, a jet of fluid, or a laser probe at atmospheric pressure to cause a portion of the substrate to vaporise to generate a plurality of gas-phase analyte molecules;
transporting at least a portion of the generated gas-phase analyte molecules into a vacuum chamber of a mass spectrometer, wherein a surface of the vacuum chamber is arranged for ionising analyte molecules;
causing at least a portion of the generated gas-phase analyte molecules to be ionized by impacting upon said surface of the vacuum chamber of the mass spectrometer to form analyte ions; and
mass analysing at least a portion of the analyte ions;
wherein the substrate comprises a pharmaceutical tablet and wherein the method comprises detecting one or more active ingredients or bulking agents in the substrate.

Assignees

• Micromass Ltd

Inventors

• Pringle Steven Derek
• Morris Michael Raymond
• Smith Stephen
• Mccullagh Michael

Classifications

• H01J49/16 Primary

  using surface ionisation, e.g. field-, thermionic- or photo-emission · CPC title

• H01J49/06

  Electron- or ion-optical arrangements · CPC title

• H01J49/10

  Ion sources; Ion guns · CPC title

• A61B17/320068

  using mechanical vibrations, e.g. ultrasonic (A61B17/22012 takes precedence; dental tooth drilling devices operated by vibration A61C3/03; removing intra-ocular material using mechanical vibrations A61F9/00745) · CPC title

• A61B17/3203

  Fluid jet cutting instruments · CPC title