Inductively coupled plasma mass spectrometer

An inductively coupled mass spectrometer for detecting impurities present in infinitesimal concentrations in a sample, said spectrometer comprising:

• a nebulizer connected to receive a solution of the sample;
• a first gas flow controller connected to deliver a gas at a controlled flow rate to said nebulizer for causing said nebulizer to produce a spray in the form of a mist composed of droplets of the sample solution;.
• a spray chamber disposed for receiving the spray and classifying the droplets in the spray;
• a plasma torch composed of three tubes, including an outer tube, a middle tube nested within said outer tube and a center tube nested within said middle tube, said center tube being connected to said spray chamber to receive said classified spray droplets from said spray chamber, and said outer tube and middle tube being connected to each receive a gas, said torch being operative for conducting a stream composed of the sample solution received by said center tube and the gas received by each of said middle tube and said outer tube
• a high frequency power source and a work coil coupled to said plasma torch for supplying energy to generate and maintain a plasma which ionizes the sample solution in the stream;.
• a mass detector disposed for receiving the ionized sample solution from said plasma torch and operative for detecting impurities in the ionized sample solution;
• and
• a second gas introducing means coupled to said center tube of said plasma torch for delivering a flow of argon gas into said plasma torch, wherein said second gas introducing means introduce the argon gas into said spray chamber along a path which is external to said nebulizer.