Improving sensitivity of electrochemical sensors with convective transport in free-standing, carbon nanotube structures

SENSORS AND ACTUATORS B-CHEMICAL

卷:246

Article

Brownlee, Benjamin J.¹  Marr, Kevin M.¹  Claussen, Jonathan C.²  Iverson, Brian D.¹ 

[1] Brigham Young Univ, Dept Mech Engn, Provo, UT 84602 USA

[2] Iowa State Univ, Dept Mech Engn, Ames, IA 50011 USA

关键词: Electrochemical;    Amperometric sensing;    Carbon nanotube;    Platinum;    Microfluidics;    Convection;   

DOI  :  10.1016/j.snb.2017.02.037

来源: Elsevier

【 摘 要 】

High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convective mass transfer enhancement was shown to improve PN-CNT sensor performance in the non-enzymatic, amperometric sensing of hydrogen peroxide (H2O2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in stirred environments for sensors with through-channel diameters of 16 Through-flow sensing produced drastically higher signals than stirred sensing with over 90% of the H2O2 being oxidized as it passed through the PN-CNT sensor, even for low concentrations in the range of 50 nM to 500 mu M. This effective utilization of the analyte in detection demonstrates the utility of exploiting convection in electrochemical sensing. For through-flow at 100 mu Ls(-1), a sensitivity of 24,300 mu A mM(-1) cm(-2) was achieved based on the frontal projected area (871 mu A mM(-1) cm(-2) based on the nominal microchannel surface area), with a 0.03 mu M limit of detection and a linear sensing range of 0.03-500 mu M. (C) 2017 Elsevier B.V. All rights reserved.

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