Multiscale modeling of VOC-graphene nanostructure interactions: designing new sorbents for portable mass spectrometric applications

In this study, we conducted an extensive computational investigation using various theoretical approaches to elucidate the molecular-level interactions between ten representative volatile organic compounds (VOCs) and functionalized graphene nanosheets. Our objective was to identify graphene modifications capable of binding the selected VOCs, which are otherwise challenging to trap and analyze in portable membrane inlet mass spectrometric (MIMS) systems. This computational study employed a combination of semiempirical and quantum mechanical calculations complemented by molecular dynamics (MD) simulations. Semiempirical quantum mechanical calculations were performed using the GFN2-xTB method to obtain binding energy information between VOCs and nanostructures. Quantum mechanical calculations based on density functional theory (DFT) with selected density functionals were utilized to study the most important local reactivity descriptors and to analyze the intermolecular noncovalent interactions. Additionally, MD simulations were employed further to evaluate the binding and desorbing capabilities of the selected system. The findings of our study suggest that graphene surfaces functionalized with OH groups have significant potential to serve as a foundation for designing new sorbents capable of efficiently trapping butyric and isobutyric acids in portable MIMS systems. In this study, we conducted an extensive computational investigation using various theoretical approaches to elucidate the molecular-level interactions between ten representative volatile organic compounds and functionalized graphene nanosheets.