Answer 15.3

a) Write down a collection of the ionization methods of inorganic mass spectrometry. Give their full name, the usual acronym, and describe the working principle with a few words.

Thermal ionization mass spectrometry, TIMS: uses high temperature to create ions of metals, metal oxides, and salts deposited on a tungsten or rhenium ribbon and to desorb them.

Spark source mass spectrometry, SSMS: high voltage discharges between electrodes made of the sample or at least containing it in an inert matrix (C, Ag, Au) are used to create atomic ions.

Glow discharge mass spectrometry, GDMS: a glow discharge, i.e., a low-temperature plasma, between an ion source housing a cathode bearing the sample ablates atoms and ionizes them in a dilute argon atmosphere.

Inductively coupled plasma mass spectrometry, ICP-MS: particulate sample or sample solution is injected into an argon plasma that is maintained by a radiofrequency magnetic field.

Secondary ion mass spectrometry, SIMS: energetic primary ions cause desorption/ionization from surfaces. Proper choice of primary ions and their energy allows variation of the process to analyze atomic or – to a certain degree – molecular species.

Accelerator mass spectrometry, AMS: highly accurate quantification of trace isotopes such as 14C by creation of multiply charged atoms and charge inversion in a MeV-accelerator. Mass analysis of ions entering the accelerator and of those exiting is required.

b) Which of the methods you just collected could be used for

1. quality control of an alloy: SSMS or GDMS

2. dating of archeologic samples: AMS

3. surface analysis of semiconductors: SIMS