This work analyzes and discusses several physicochemical peptide chain properties that may generate partial or total BGE slip boundary conditions on the surface of peptides migrating as spherical and aspherical particles in CZE. A definition of the BGE slip length is presented that is able to account the effect of particle curvature through the associated metrical coefficients. This definition allows the distinction between partial and total BGE slip lengths. It is also shown that the BGE slip length must be variable on orthotropic aspherical particles surfaces.