Molecular Orbital Studies on the Relative Sensitivity and the Nature of the Fragmentation from Molecular Ion of Some Biologically Important Compounds for Analytical Application of Negative Ion Chemical Ionization Mass Spectrometry

Abstract

In order to gain an insight into the effective derivatization of biologically important compounds for enhancing the sensitivity of NICIMS, the semiemprical molecular orbital calculations supported by the MINDO/3 method were carried out on the some fluorinated compounds as models of the commonly used fluorinated reagents and trifluoroacetic derivatives related to the biologically active compounds. Furthermore, to examine the nature of the fragmentation of their molecular ions, openshell molecular orbital calculations supported by the MINDO/3-UHF method were also carried out on the anion radical of the TFA-derivatives of p substituted phenols.
The results pertaining to the present calculations provided the useful informations concerning the effective derivatization for the analytical application of NICIMS.