Toward sol-gel electrochromatographic separations on a chip

A porous photopolymerized sol-gel (PSG) monolith was synthesized in the separation channel of a borosilicate glass chip via UV irradiation (5 min) of a mixture of 3-methacryloxypropyltrimethoxysilane, an acid catalyst, a porogen, and a photoinitiator. The PSG monolith adhered strongly to the chemically untreated channel walls. The chip was fabricated using standard lithography procedures to give channels that are 35-m deep and 90-m wide. Masking the other channels defined the 4.7-cm PSG section in the separation channel. Two dyes Coumarin 314 and 510 were successfully separated within baseline resolution in 225 s when fluorescent detection occurred immediately after the PSG section. The separation time was reduced to 80 s with little loss in resolution by detecting the dyes 1.2 cm from the front of the PSG monolith.