Publication: Contactless conductivity detector from printed circuit board for paper-based analytical systems
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Issued Date
2020
Resource Type
File Type
application/pdf
ISSN
399140
Other identifier(s)
2-s2.0-85070643037
Rights Holder(s)
Scopus
Bibliographic Citation
Talanta. Vol 206, (2020)
Suggested Citation
Chantipmanee N., Sonsa-Ard T., Fukana N., Kotakanok K., Mantim T., Wilairat P., Hauser P.C., Nacapricha D. Contactless conductivity detector from printed circuit board for paper-based analytical systems. Talanta. Vol 206, (2020). doi:10.1016/j.talanta.2019.120227 Retrieved from: https://hdl.handle.net/20.500.14740/4946
Abstract
This work presents a capacitively coupled contactless conductivity detector (C4D) etched out from a printed circuit board (PCB) as potential sensor for paper-based analytical systems. Two lines of any desirable pattern forming 35-μm thick planar copper electrodes were produced on a PCB plate (40 mm × 60 mm) by photolithography. The final PCB plate was covered with polypropylene film to serve as the insulating layer for the C4D detector. The film also protected the copper electrodes from corrosion. Electrodes made in this planar geometry make the PCB-C4D suitable as sensor for flat devices such as paper-based analytical devices. For this work, plain paper strips were employed as sample reservoir and as fluidic channel without hydrophobic pattern. A dried paper strip was first placed over the sensor, followed by dispensing a fixed volume of the liquid sample onto the paper. Entrapment of the liquid sample in the paper strip leads to reproducible size and position of the detection zone of the sample liquid for the capacitive coupling effect. High precision was obtained with %RSD ≤1% (n = 18) for standard solutions of KCl. Soil suspensions could be analyzed without prior filtration by placing a drop onto the paper strip extending away from the detector zone. The paper strip filtered out soil particles at the surface of the paper. Therefore, only soil filtrate moved towards the detection zone by lateral flow. The C4D detection using paper strip showed high tolerance to soil suspension with turbidity up to 6657 NTU, offering direct analysis of soil salinity. Cleaning with moist tissue paper between samples is adequate even for dirty samples such as soil suspension. We also monitored conductivity of acid-base reaction in the microfluidic paper channels, which was later applied to the quantification of bicarbonate in water and in antacid tablet (“Soda Mint Tablet”). © 2019 Elsevier B.V.
Subject(s)
Analytic equipment
Carbonates
Copper corrosion
Corrosion protection
Electrodes
Filtration
Geometry
Liquids
Particle size analysis
Plastic films
Polypropylenes
Potassium compounds
Sensors
Soils
Timing circuits
Capacitive coupling effects
Capacitively coupled
Contactless conductivity detector
Hydrophobic patterns
Paper-based analytical devices
Poly-propylene film
Printed circuit boards (PCB)
Soil salinity
Printed circuit boards
Carbonates
Corrosion Prevention
Electrodes
Filtration
Geometry
Liquids
Carbonates
Copper corrosion
Corrosion protection
Electrodes
Filtration
Geometry
Liquids
Particle size analysis
Plastic films
Polypropylenes
Potassium compounds
Sensors
Soils
Timing circuits
Capacitive coupling effects
Capacitively coupled
Contactless conductivity detector
Hydrophobic patterns
Paper-based analytical devices
Poly-propylene film
Printed circuit boards (PCB)
Soil salinity
Printed circuit boards
Carbonates
Corrosion Prevention
Electrodes
Filtration
Geometry
Liquids