Bipolar Electrode Focusing: Faradaic Ion Concentration Polarization

作者：Anand Robbyn K; Sheridan Eoin; Knust Kyle N; Crooks Richard M^*

来源：Analytical Chemistry, 2011, 83(6): 2351-2358.

DOI：10.1021/ac103302j

Bipolar electrode (BPE) focusing locally enriches charged analytes in a microchannel along an electric field gradient that opposes a counter-flow. This electric field gradient forms at the boundary of an ion depletion zone generated by the BPE. Here, we demonstrate concentration enrichment of a fluorescent tracer by up to 500 000-fold. The use of a dual-channel microfluidic configuration, composed of two microchannels electrochemically connected by a BPE, enhances the rate of enrichment (up to 71-fold/s). Faradaic reactions at the ends of the BPE generate ion depletion and enrichment zones in the two, separated channels. This type of device is equivalent to previously reported micro/nanochannel junction arrangements used for ion concentration polarization, but it is experimentally more flexible and much simpler to construct.

• 出版日期2011-3-15