The Collaborative International Dictionary of English v.0.48:

Spectrometry \Spec*trom"e*try\, n. (Physics)
   Art or process of using a spectrometer, of any type; -- when
   used alone, it usually refers to the use of a spectrometer
   using light in the visible, infrared, or ultraviolet region.
   -- Spec`tro*met"ric, a.
   [Webster 1913 Suppl. +PJC]

   mass spectrometry, the art or process of using a mass
      spectrometer to analyse chemical samples.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

mass spectrometry \mass spectrometry\ mass spectroscopy \mass
spectroscopy\n.
   1. (Physics, Chemistry) A method for identifying chemical
      composition of substances by use of a mass spectrometer.
      [PJC]