There is provided an integrated system for liquid separation, such as LC, CE, affinity chromatography, and ion exchange chromatography, comprising a column and end-fittings embedded in a plastic material, such as a thermoplastic polymer. The system may further comprise an electrospray emitter directly connected with the outlet of the column, wherein a substantial part of the emitter is covered with the polymer material. There is also provided a method by which a separation column along with the accompanying end fittings for connection with adjacent liquid conduits is embedded in a polymer matrix. This configuration e.g. ensures that the factory-made, correct attachment of the fittings to the column is preserved (since the matrix prevents further user intervention, accidental or otherwise). Accordingly, the responsibility for the correct attachment of the fittings is shifted from the end user to the manufacturer.