Ionic Liquid-Packed Microfluidic Device with Non-Planar Microelectrode as a Miniaturized Electrochemical Gas Sensor

Sreerag Kaaliveetil, Yun Yang Lee, Zhenglong Li, Yu Hsuan Cheng, Niranjan Haridas Menon, Saudagar Dongare, Burcu Gurkan, Sagnik Basuray

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Integrating transducer/sensing materials into microfluidic platforms has enhanced gas sensors′ sensitivity, selectivity, and response time while facilitating miniaturization. In this manuscript, microfluidics has been integrated with non-planar microelectrode array and functionalized ionic liquids (ILs) to develop a novel miniaturized electrochemical gas sensor architecture. The sensor employs the IL 1-ethyl-3-methylimidazolium 2-cyanopyrolide ([EMIM][2-CNpyr]) as the electrolyte and capture molecule for detecting carbon dioxide (CO2). The three-layer architecture of the sensor consists of a microchannel with the IL sandwiched between glass slides containing microelectrode arrays, forming a non-planar structure. This design facilitates electric field penetration through the IL, capturing CO2 binding perturbations throughout the channel volume to enhance sensitivity. CO2 binding with [EMIM][2-CNpyr] generates carboxylate ([EMIM]+-CO2]), carbamate ([2-CNpyr]-CO2]), and pyrrole-2-carbonitrile (2-CNpyrH) species, significantly decreasing the conductivity. The viscosity is also increased, leading to a further decrease in conductivity. These cumulative effects increase charge transfer resistance in the impedance spectrum, allowing a linear calibration curve obtained using Langmuir Isotherm. The sensitivity and reproducibility in CO2 detection are demonstrated by two electrode configurations using the calibration curve. The developed sensor offers a versatile platform for future applications.

Original languageEnglish (US)
Article number087508
JournalJournal of the Electrochemical Society
Issue number8
StatePublished - 2023

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry


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