Small-molecule-based mass spectrometry methods

SMALL MOLECULE-BASED MASS SPECTROMETRY METHODS... 

Typical fragmentation of both types of base involves the loss of small neutral molecules such as HCN, CO, and CH3CN, as well as some extensive rearrangements in aromatic compounds. The most common derivatization, silylation under normal conditions (TMSC, HMDS/TMSC, BSA, or BSTFA/TMSC, V, 20 min - 2 hr), with or without pyridine as a solvent and base catalyst, usually leads to the enolic forms of the bases via the corresponding silyl ether. The persilylated derivatives are volatile enough to be used in gas chromatography-mass spectrometry (GC-MS). This enhancement of volatility compared to that of the free bases is the key factor making GC-MS a widely used analytical method in this area. 

This book is based on the reactions of thermal electrons with molecules. The ECD, negative-ion chemical ionization (NICI) mass spectrometry, and polaro-graphic reduction in aprotic solvents methods are used to determine the kinetic and thermodynamic parameters of these reactions. The chromatograph gives a small pure sample of the molecule. The temperature dependence of the response of the ECD and NIMS is measured to determine fundamental properties. The ECD measurements are verified and extended by correlations with half-wave reduction potentials in aprotic solvents, absorption spectra of aromatic hydrocarbons and donor acceptor complexes, electronegativities, and simple molecular orbital theory. 

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