A magnetically excited microwave plasma source for atomic emission spectroscopy with performance approaching that of the inductively coupled plasma

A novel magnetically excited microwave plasma emission source was developed and tested. Unlike previous microwave plasma sources which couple energy from the microwave electric field, this source couples energy from the magnetic field. The resultant plasma shape allows easy entrainment of wet sample aerosol, such as is produced by a conventional inductively coupled plasma (ICP) nebulizer and spray chamber, into the core of the plasma. Plasma support gas can be either nitrogen or air although better sensitivity is achieved using nitrogen. Good stability of operation was observed for both aqueous and organic solvents over a wide range of sample flows. The measured performance when used as a spectroscopic source in conjunction with an echelle polychromator showed detection limits approaching those of commercial ICP sources.