Determination of metal cations on miniaturised planar polymeric separationdevices using isotachophoresis with integrated conductivity detection

The feasibility of using miniaturised planar polymeric separation devices f or the isotachophoretic separation of metal cations was demonstrated. Devic es were produced in silicone rubber using a cast moulding fabrication techn ique. Detection was performed using an integrated single electrode conducti vity detector, a design which offers simple fabrication and high resolution . The electrical characteristics of the devices were found to be suitable f or performing electroseparations with a power dissipation of up to 1.5 W m( -1) being achieved. The separation of a sample containing a mixture of the four metal ions lithium, lanthanum, dysprosium and ytterbium was reproducib ly achieved using miniaturised devices. A comparison with a capillary scale separation of the same mixture was made. The miniaturised separations were achieved in under 600 s, which is less than half the time taken for the ca pillary scale separations.