A method for determining at least one characteristic parameter of a sample of a substance comprising readable particles in a liquid is disclosed. The method is specifically beneficial where the readable particles comprises a plurality of particle species. The method comprises obtaining Taylor dispersion data comprising a plurality of data sets describing a Taylor dispersion signal profile of the readable particles of the sample; fitting the Taylor dispersion data to a fitting equation (2) Stot(t)=f(p(t); α, β*A+B, wherein Stot(t) is the total signal at the time t, A is a response factor, B is a baseline constant, p(t) is an instrument factor function and α and β are fitting constants; determine at least one of the fitting constants α and β; and determining the at least one characteristic parameter of the sample based on the one or more of the fitting constants α and β.