Real-Time Detection of Small Aliphatic Compounds in Alcohol by Surface Plasmon Resonance Using N Doped Graphene

With the advancement of semiconductor manufacturing technology, the interest in high-purity isopropyl alcohol (IPA) has been growing, leading to increased demand for real-time detection of contaminants in IPA. Although various technologies have been developed to accurately detect impurities, there have been limitations in achieving rapid, reversible, and real-time detection. Herein, we report an N doped graphene (N-Gr) based surface plasmon resonance (SPR) sensor capable of detecting acetone at ppb-level dissolved in IPA and this sensor confirms the real-time detection of acetone with great reversibility and repeatability. Nitrogen dopants introduced into graphene via plasma treatment were thoroughly characterized using Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The nitrogen dopants have been identified to form three distinct types of sites in graphene – graphitic, pyrrolic, and pyridinic – each imparting unique electrostatic characteristic to the graphene lattice. The adsorption of acetone to N-Gr is found to be stronger than that to pristine graphene because of electrostatic interaction, and the doping effect of N-Gr is demonstrated through density functional theory calculations and enhancement in sensing performance of N-Gr based SPR sensor. This study offers experimental and theoretical insights into the adsorption kinetics of acetone dissolved in IPA and provides promising perspectives for real-time sensing technology utilizing N-Gr to detect impurities in high-purity cleaning agents. Keywords: Surface plasmon resonance, Aliphatic compounds , N doped Graphene, Density functional theory