119th General Meeting of the KCS

Type Poster Presentation
Area 분석화학
Room No. 포스터발표장
Time 4월 21일 (금요일) 13:00~14:30
Code ANAL.P-196
Subject Theoretical calculation of collision cross section for ions in nitrogen buffer gas
Authors 고태원, 김준곤*
고려대학교 화학과, Korea
Abstract In ion mobility spectrometry (IMS), repeated collisions between gas-phase ions and neutral buffer gas molecules occur under weak and uniform electric field. The collisions affect ion mobility, which is directly related to ion collision cross section (CCS). CCS is related to ion structure, and different structural isomers show different CCS to be separated during IMS. Then, ion structures can be revealed based on theoretical tools for calculating ion CCS. Accurate description of intermolecular interactions between gas-phase ions and neutral buffer gas molecules is a key factor in estimating theoretical CCS of ions. Nitrogen is a popular neutral buffer gas for IMS and is a linear molecule with quadrupole moment and a large polarizability. Thus, the use of nitrogen as the buffer gas in IMS allows separation of ions with similar structures but distinct dipole moments, which is typically not possible with other drift gases such as helium. At the same time, however, the complexity of the nitrogen gas makes it difficult to develop an accurate theoretical tool for calculating the CCS of ions in nitrogen. Here we present a more accurate calculation method for calculating ion CCS in nitrogen drift gas that are comparable with experimental results. We investigate the influence of van der Waals, ion-induced dipole, and ion-quadrupole interactions on theoretical CCS and optimize these interactions to reduce the error between experimental and theoretical CCS. Through these experiments and calculations, it becomes possible to obtain a more valid and powerful theoretical calculation method.
E-mail ktw7863@korea.ac.kr