This paper shows the applicability of a disposable and inexpensive microfluidic chip for electrochromatographic separations. The chip, recently developed by us for chip-based LC, was fabricated from PDMS incorporating conventional chromatographic RP silica particles (C18) without the use of frits. Three cephalosporin antibiotics were used to demonstrate the applicability of the chip-based chromatographic packing for electrochromatographic determinations. The used sample injection method utilizes hydrodynamic pressure, thereby, reducing the propensity for sample bias during the injection.