Malaysian Journal of Analytical Sciences, Vol 26 No 6 (2022): 1249 - 1259

 

MODELING THE TIME RESPONSE OF CURRENT USING INTERDIGITATED ARRAYS IN A SHALLOW

ELECTROCHEMICAL CELL

 

(Pemodelan Respons Arus Mengunakan Susunan Interdigital dalam Sel Elektrokimia Cetek)

 

Cristian F. Guajardo Yévenes1,2,* and Werasak Surareungchai3,4

 

1Biological Engineering Program, Faculty of Engineering,

2Pilot Plant Development and Training Institute,

3Nanoscience and Nanotechnology Graduate Program,

4School of Bioresources and Technology,

King Mongkut’s University of Technology Thonburi,

49 Soi Thian Thale 25, Thanon Bang Khun Thian Chai Thale

Bangkok 10150, Thailand

 

*Corresponding author: cristian.gua@kmutt.ac.th

 

 

Received: 9 February 2022; Accepted: 25 July 2022; Published:  27 December 2022

 

 

Abstract

The interdigitated array of electrodes (IDAE) is a common choice for integration in small electrochemical sensors due to the amplified currents and fast response times. The design and assessment of IDAE performance in microfluidic cells require the use of mathematical models, in which the diffusion equation is widely applied. Analytical solutions for this equation are available for IDAEs in tall cells; however, they are not currently available for shallow cells, as is the case with microfluidic devices. The issue of whether it is possible to model the time response of IDAEs in shallow cells using simple exponential functions is addressed in this work. This is achieved by numerically solving the diffusion equation to obtain the time response of the current and later by applying non-linear regression to obtain exponential models. The current response is generally complex due to the many Fourier harmonics involved. However, the findings reveal that when the elapsed time is greater than some characteristic time, the current response can be approximated by an exponential curve. Furthermore, higher currents can be obtained at the expense of longer response times when the cell is tall, while shorter response times can be obtained at the expense of lower currents when the cell is shallow.

 

Keywords: Shallow electrochemical cell, Interdigitated arrays, Numerical simulation, Current response.

 

Abstrak

Elektrod susunan interdigital (IDEA) adalah pilihan biasa bagi intergrasi dalam sensor elektrokimia kecil berdasarkan arus teramplikasi dan respons masa yang pantas. Rekabentuk dan penilaian bagi prestasi IDEA di dalam sel mikrobendalir memerlukan pemodelan matematik, di mana persamaan resapan digunakan secara meluas. Penyelesaian analitikal bagi persamaan ini sesuai bagi IDEA dalam sel tinggi; namun belum ada bagi sel cetek, khusus bagi kes bersama mikrobendalir. Isu terhadap kebarangkalian ia berhasil terhadap model respons masa di dalam sel cetek menggunakan fungsi eksponen mudah telah dikaji. Ia dicapai melalui penyelesaian berangka persamaan resapan untuk mendapatkan respons masa bagi arus dan kemudian digunakan bagi regresi tak linear untuk mendapatkan model eksponen. Respons arus secara umum adalah kompleks disebabkan oleh penglibatan harmonik Fourier. Namun, hasil kajian mendapati apabila masa berlalu lebih kuat berbanding masa pencirian, responsa arus boleh dianggar oleh lengkung eksponen. Selanjutnya, arus yang tinggi boleh diperolehi pada masa respons yang lebih lama apabila susunan sel adalah tinggi, sebaliknya masa respons yang lebih pendek diperolehi pada arus yang rendah di mana kedudukan sel adalah cetek.

 

Kata kunci: sel elektrokimia cetek, susunan interdigital, simulasi berangka, respons arus

 

Graphical Abstract


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