Diathermy Knife Ionisation Source

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 analysed by contacting the substrate with a diathermy knife. An electric current is applied to the diathermy knife such that the diathermy knife vaporises a portion of the substrate. The vapour 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 ionised to form analyte ions which are then mass analysed.

1 . A non-surgical method of mass spectrometry comprising:
 probing a substrate with a probe at atmospheric pressure to generate analyte molecules;   transporting at least a portion of the generated analyte molecules into a vacuum chamber of a mass spectrometer;   causing at least a portion of the generated analyte molecules to be ionised within the vacuum chamber of the mass spectrometer to form analyte ions; and   mass analysing at least a portion of the analyte ions.   
     
     
         2 . A method as claimed in  claim 1 , wherein the probe comprises an electrode and wherein the method further comprises applying an electric current to the electrode to generate the analyte molecules. 
     
     
         3 . A method as claimed in  claim 2 , wherein the step of applying the electric current to the electrode causes a portion of the substrate to vaporise and form the analyte molecules. 
     
     
         4 . A method as claimed in  claim 1 , wherein the probe comprises a diathermy knife or an electrosurgical RF knife. 
     
     
         5 . A method as claimed in  claim 1 , wherein the probe is arranged to direct a jet of fluid onto the substrate to generate the analyte molecules. 
     
     
         6 . A method as claimed in  claim 1 , wherein the probe comprises an ultrasonic probe or a laser probe. 
     
     
         7 . A method as claimed in  claim 1 , further comprising aspirating the analyte molecules via a tube or supply line into the mass spectrometer. 
     
     
         8 . 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. 
     
     
         9 . A method as claimed in  claim 1 , wherein at least a portion of the analyte molecules are ionised upon impacting a surface within the vacuum chamber. 
     
     
         10 . 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. 
     
     
         11 . A method as claimed in  claim 1 , wherein the analyte molecules are ionised by an ion source located within the vacuum chamber. 
     
     
         12 . 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.   
     
     
         13 . 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. 
     
     
         14 . A method as claimed in  claim 1 , further comprising detecting if one or more compounds, chemicals or contaminants are present in the substrate above a predetermined concentration. 
     
     
         15 . A method as claimed in  claims 14 , wherein at least one of the compounds, chemicals or contaminants comprises a pesticide, a steroid or other drug. 
     
     
         16 . A method as claimed in  claim 14 , wherein at least one of the compounds, chemicals or contaminants comprises a bulking material. 
     
     
         17 . A method as claimed in  claim 1 , wherein the substrate comprises a pharmaceutical tablet or other pharmaceutical product and wherein the method comprises detecting one or more active ingredients or bulking agents in the substrate. 
     
     
         18 . A method as claimed in  claim 1 , wherein the substrate comprises a solid, gel or powder. 
     
     
         19 . A method of mass spectrometry comprising:
 probing a substrate with a probe at atmospheric pressure to generate analyte molecules;   transporting at least a portion of the generated analyte molecules into a vacuum chamber of a mass spectrometer;   causing at least a portion of the analyte molecules to be ionised within the vacuum chamber of the mass spectrometer upon impacting a surface within the vacuum chamber so as to form analyte ions; and   mass analysing at least a portion of the analyte ions.   
     
     
         20 . A method as claimed in  claim 19 , wherein the probe is selected from the group consisting of an electrode, a diathermy knife, an electrosurgical RF knife, a laser probe, an ultrasonic probe, and a jet of fluid.