Solid phase extraction on microfluidic devices

A microfabricated device with C18-coated channels was used to demonstrate on-chip solid phase extraction. Sample solutions containing a neutral dye were enriched and eluted in less than 4 min. Distinct elution peaks with good signal-to-noise ratios were obtained even for highly dilute samples. The gain in concentration estimated from the enrichment and elution volumes was 80-fold.