A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices

In this work, a new capacitively coupled contactless conductivity detection (C<sup>4</sup>D) sensor for microfluidic devices is developed. By introducing an LC circuit, the working frequency of the new C<sup>4</sup>D sensor can be lowered by the adjustments of the inductor an...

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Main Authors: Yuchen He, Qiang Huang, Yu He, Haifeng Ji, Tao Zhang, Baoliang Wang, Zhiyao Huang
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/21/19/6381
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author Yuchen He
Qiang Huang
Yu He
Haifeng Ji
Tao Zhang
Baoliang Wang
Zhiyao Huang
author_facet Yuchen He
Qiang Huang
Yu He
Haifeng Ji
Tao Zhang
Baoliang Wang
Zhiyao Huang
author_sort Yuchen He
collection DOAJ
description In this work, a new capacitively coupled contactless conductivity detection (C<sup>4</sup>D) sensor for microfluidic devices is developed. By introducing an LC circuit, the working frequency of the new C<sup>4</sup>D sensor can be lowered by the adjustments of the inductor and the capacitance of the LC circuit. The limits of detection (LODs) of the new C<sup>4</sup>D sensor for conductivity/ion concentration measurement can be improved. Conductivity measurement experiments with KCl solutions were carried out in microfluidic devices (500 µm × 50 µm). The experimental results indicate that the developed C<sup>4</sup>D sensor can realize the conductivity measurement with low working frequency (less than 50 kHz). The LOD of the C<sup>4</sup>D sensor for conductivity measurement is estimated to be 2.2 µS/cm. Furthermore, to show the effectiveness of the new C<sup>4</sup>D sensor for the concentration measurement of other ions (solutions), SO<sub>4</sub><sup>2−</sup> and Li<sup>+</sup> ion concentration measurement experiments were also carried out at a working frequency of 29.70 kHz. The experimental results show that at low concentrations, the input-output characteristics of the C<sup>4</sup>D sensor for SO<sub>4</sub><sup>2−</sup> and Li<sup>+</sup> ion concentration measurement show good linearity with the LODs estimated to be 8.2 µM and 19.0 µM, respectively.
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spelling doaj.art-826a83c146e744f4a5e9e76c7c6da9902023-11-22T16:45:14ZengMDPI AGSensors1424-82202021-09-012119638110.3390/s21196381A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic DevicesYuchen He0Qiang Huang1Yu He2Haifeng Ji3Tao Zhang4Baoliang Wang5Zhiyao Huang6State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaState Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaState Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaState Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaState Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaState Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaState Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaIn this work, a new capacitively coupled contactless conductivity detection (C<sup>4</sup>D) sensor for microfluidic devices is developed. By introducing an LC circuit, the working frequency of the new C<sup>4</sup>D sensor can be lowered by the adjustments of the inductor and the capacitance of the LC circuit. The limits of detection (LODs) of the new C<sup>4</sup>D sensor for conductivity/ion concentration measurement can be improved. Conductivity measurement experiments with KCl solutions were carried out in microfluidic devices (500 µm × 50 µm). The experimental results indicate that the developed C<sup>4</sup>D sensor can realize the conductivity measurement with low working frequency (less than 50 kHz). The LOD of the C<sup>4</sup>D sensor for conductivity measurement is estimated to be 2.2 µS/cm. Furthermore, to show the effectiveness of the new C<sup>4</sup>D sensor for the concentration measurement of other ions (solutions), SO<sub>4</sub><sup>2−</sup> and Li<sup>+</sup> ion concentration measurement experiments were also carried out at a working frequency of 29.70 kHz. The experimental results show that at low concentrations, the input-output characteristics of the C<sup>4</sup>D sensor for SO<sub>4</sub><sup>2−</sup> and Li<sup>+</sup> ion concentration measurement show good linearity with the LODs estimated to be 8.2 µM and 19.0 µM, respectively.https://www.mdpi.com/1424-8220/21/19/6381contactless conductivity detectioncapacitively coupled contactless conductivity detection (C<sup>4</sup>D)microfluidiclab on a chip
spellingShingle Yuchen He
Qiang Huang
Yu He
Haifeng Ji
Tao Zhang
Baoliang Wang
Zhiyao Huang
A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices
Sensors
contactless conductivity detection
capacitively coupled contactless conductivity detection (C<sup>4</sup>D)
microfluidic
lab on a chip
title A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices
title_full A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices
title_fullStr A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices
title_full_unstemmed A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices
title_short A Low Excitation Working Frequency Capacitively Coupled Contactless Conductivity Detection (C<sup>4</sup>D) Sensor for Microfluidic Devices
title_sort low excitation working frequency capacitively coupled contactless conductivity detection c sup 4 sup d sensor for microfluidic devices
topic contactless conductivity detection
capacitively coupled contactless conductivity detection (C<sup>4</sup>D)
microfluidic
lab on a chip
url https://www.mdpi.com/1424-8220/21/19/6381
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