title: In situ analysis of dynamic laminar flow extraction using surface-enhanced Raman spectroscopy.
abstract: In this study, we performed micro-scale dynamic laminar flow extraction and site-specific in situ chloride concentration measurements. Surface-enhanced Raman spectroscopy was utilized to investigate the diffusion process of chloride ions from an oil phase to a water phase under laminar flow. In contrast to common logic, we used SERS intensity gradients of Rhodamine 6G to quantitatively calculate the concentration of chloride ions at specific positions on a microfluidic chip. By varying the fluid flow rates, we achieved different extraction times and therefore different chloride concentrations at specific positions along the microchannel. SERS spectra from the water phase were recorded at these different positions, and the spatial distribution of the SERS signals was used to map the degree of nanoparticle aggregation. The concentration of chloride ions in the channel could therefore be obtained. We conclude that this method can be used to explore the extraction behaviour and efficiency of some ions or molecules that enhance the SERS intensity in water or oil by inducing nanoparticle aggregation.
authors.affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai, 200237, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai, 200237, P. R. China.
authors.forename: Hua-Lin
authors.initials: HL
authors.lastname: Wang
authors.affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai, 200237, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai, 200237, P. R. China.
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Bioreactor Engineering &Department of Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Yi-Tao
authors.initials: YT
authors.lastname: Long