Gas phase ion/molecule reactions and analytical applications by tandem mass spectrometry

Guodong Chen, Purdue University

Abstract

Fundamental studies and analytical applications by tandem mass spectrometry are described in this thesis. Gas phase ion/molecule reactions involving W(CO)$\sb6$ and perfluorohexane (C$\sb6$F$\sb{14})$ are used to study mechanisms related to ion/surface collisions. A single collision event is suggested to be responsible for multiple fluorine atoms pick-up during collisions of tungsten-containing ions with fluorinated self-assembled monolayer surfaces. Gas phase "interrupted sigma bonds" are realized in the cluster ions involving TEMPO and phenoxyl radical with (OCNCO) $\sp{+},$ S$\sp{+.}$ and CS$\sp{+.}.$ Thermochemical information is obtained by the kinetic method, a procedure involving dissociation of mass-selected cluster ions. Various ionization methods are used to generate various cluster ions, including polyatomic cation bound dimers, proton-bound dimers, electron-bound dimers, dimeric radical cations and ionic cluster ions. Their dissociation yields valuable thermochemical quantities, including polyatomic cation affinity, proton affinity, electron affinity, ionization energy and heterolytic bond dissociation energy. Energy partitioning information is also available using the kinetic method and RRKM calculations. Desorption chemical ionization mass spectrometry is used in conjunction with statistical calculations to determine monomer distributions in isocyanate copolymers. The alkyl/alkoxy substituted isocyanate copolymers are shown to have random distributions and alkyl/fluorinated alkyl substituted isocyanate copolymers exhibit block distributions of monomers.

Degree

Ph.D.

Advisors

Cooks, Purdue University.

Subject Area

Analytical chemistry

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