Gold nanoparticle-enhanced microchip capillary electrophoresis

We describe here the use of gold nanoparticles in conjunction with chip-bas ed capillary electrophoresis to improve the selectivities between solutes a nd to increase the efficiency of the separation. We coated the microchannel wall of a microfluidic device with a layer of poly(diallyldimethylammonium chloride) (PDADMAC) and then collected on it citrate-stabilized gold nanop articles. The resolutions and the plate numbers of the solutes were doubled in the presence of the gold nanoparticles. Such selectivity improvements r eflect changes in the observed mobility accrued from interactions of solute s with the particle surface. The electrochemical detection and the quantita tion of the solutes were not effected by the PDADMAC and the gold nanoparti cles.