Methods for identifying a biological particle in a sample medium include generating an Electrophoretic Quasi-elastic Light Scattering (EQELS) spectrum for the biological particle in the sample medium. The EQELS spectrum is compared to a reference database comprising a plurality of spectra, and each of the plurality of spectra correspond to an EQELS spectrum for one of a plurality of known biological particles. The biological particle in the sample medium is identified from the comparison.