Systematic Investigation on Difference in (+) APPI Efficiency of Ortho, Meta, and Para Isomers
Syful Islam1, Arif Ahmed1, Nissa Nurfajrin Solihat1, Thamina Acter1 and Sunghwan Kim1,2
1Kyungpook National University, Department of Chemistry, Daegu, 41566, Republic of Korea.
2Green-Nano Materials Research Center, Daegu, 41566, Republic of Korea.
Understanding the underlying principle behind the ionization technique is important to improve sensitivity and selectivity of mass spectrometry (MS) analysis. Analyte-solvent interaction is one of the important factors affecting ionization process. In this study, the analyte-solvent interaction was investigated by use of a series of ortho, meta and para isomers, (+) Atmospheric Pressure Photo-Ionization Mass Spectrometry (APPI-MS) and theoretical calculation. Experimental results show that isomers can have vastly different ionization efficiency despite that they have the same elemental formulae and functional groups. To understand the reason behind the phenomenon, various forms of analyte-solvent radical ion complexes were investigated by use of quantum mechanical calculations. The reasons that could contribute to this different ion formation behavior of compounds were thoroughly investigated.