Abstract
This paper reports a novel label-free concentration determination method for nanofluidics: solvent-enhanced photothermal optical diffraction. Our method realized concentration determination with a detection limit of fewer than 10 molecules. Furthermore, we applied our method to normal-phase chromatography and demonstrated femtoliter sample separation and label-free detection in 10 2 nm channel. Our method will be widely used for various chemical/biological analyses utilizing nanofluidics.