Abstract
We established an interface of mass spectrometry based on nanofluidics. After applying a high voltage, liquid sample was converted to fL-droplets by gas-phase flow focusing in micro/nanochannels, and they were ejected into a mass spectrometer (MS) with 100% efficiency by trajectory control, which has been difficult for conventional MS interface by electrospray ionization (ESI) with sample dispersion. The injected droplets were evaporated to generate gas-phase analyte ions by heat transfer. We realized 290 times higher MS sensitivity compared to conventional ESI for the first time. The method will greatly contribute to the state-of-the-art analyses such as single-cell proteomics.