A microfluidic emitter based on three-dimensional hydrodynamic focusing was developed to generate a wrapped charged aerosol plume, in which the distribution of the sample ion in the nanoelectrospray could be regulated. Deposition patterns of the wrapped spray from the proposed three-dimensional hydrodynamic focusing nanoelectrospray emitter (3D HFNE) were collected under different conditions to ensure the wrapped configuration. Moreover, sample ion intensities as well as their ratios to a focusing background ion were studied as a function of different displacements from the center of the wrapp...
