Disclosed herein is a device for characterizing a biological sample or an airborne sample. According to embodiments of the present disclosure, the device comprises an electrospray source, a mass analyzer, a charge detector, and optionally, an ion guide. The present device is useful in analyzing the particle population in the biological or airborne sample based on the mass to charge (m/z) ratio and the charge (z) of each particle. Also disclosed herein are the methods of making a diagnosis of cancer by use of the present device, and methods of determining the mass distribution of particles in an airborne sample.