K. Mathwig, S. Kang, D. Mampallil and S. G. Lemay
Pushing the Limits of Electrical Detection of Ultralow Flows in Nanofluidic Channels
Proceeding of the 1st International Conference on Microfluidic Handling Systems, Enschede, The Netherlands, Oct. 10 – 12 (2012) 18.
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This paper presents improvements in flow detection by electrical cross-correlation spectroscopy. This new technique detects molecular number fluctuations of electrochemically active analyte molecules as they are transported by liquid flow through a nanochannel. These fluctuations are used as a marker of liquid flow as their time of flight in between two consecutive transducers is determined, thereby allowing for the measurement of liquid flow rates in the picoliter-per-minute regime. Here we show an enhanced record-low sensitivity below 1 pL/min by capitalizing on improved electrical instrumentation, an optimized sensor geometry and a smaller channel cross section.