End Labelled Free Solution Electrophoresis (ELFSE) provides a means of separating polymer molecules such as ssDNA according to their size, via free solution electrophoresis, thus eliminating the need for polymer separation via gels or polymer matrices. Here, significant improvements in ELFSE are disclosed via concurrent exposure of the polymer molecules to an electroosmotic flow. When the methods are applied to DNA sequencing by ELFSE, significant improvements in read length are observed.