Electrochemical Analysis in Picoliter Microvials

Lithographically fabricated templates have been used to imprint picoliter to femtoliter microvials in polystyrene. The clear microvials produced in conjunction with a transmission optical microscope and micromanipulators make it possible to handle volumes as small as 1 pL. Voltammetry has been carried out in these well-defined microenvironments with restriction of reagents near the electrode surface. Ferrocenecarboxylic acid has been utilized to characterize the electrochemical response in these ultrasmall volumes. Sigmoidal voltammograms (0.4−2 V/s) are obtained for vial sizes down to 1 pL.