Fluid Temperature Measurement in Aqueous Solution via Electrochemical Impedance

Baldwin, Alex; Yoon, Eugene; Hudson, Trevor; Meng, Ellis

doi:10.1109/jmems.2019.2939811

Cited by 6 publications

(2 citation statements)

References 43 publications

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“…Despite its extensive use in biological and biomedical systems, its application in sensors for quantifying physical quantities remains limited [19][20]. Accurate EI measurements allowed precise flow rate measurements using a thin-film metallic heater with reported sensitivities and resolutions in temperature measurements [21,22]. Despite achieving a resolution of 17 μL/min and an overheat of 6.17 °C, challenges persist in the accurate detection of flow rates over a range of 43-200 μL/min [22].…”

Section: Fig 1: Principles Of Physics For Flow Rate Measurementmentioning

confidence: 99%

Modeling the coulometric data for on-chip flow rate detection as a first order decay problem in a microfluidic device

Deswal,

Pandey,

Singh

et al. 2024

Microfluidics, BioMEMS, and Medical Microsystems XXII

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On-chip detection of flow rates in microfluidics is critical to lab-on-chip technology. Thermal sensing techniques although widely used are limited by temperature rise of the fluid and issues involving integration inside a microchannel. Electrochemical methods present a reliable alternative. Among the widely used electrochemical techniques, Coulometry measures the charge consumed in a redox reaction at electrode surface. In present work, constant potential coulometry at 2V was performed using an electrochemical workstation on Titanium-Platinum microelectrodes (micropatterned on Si wafer substrate) submerged in a moving 0.1 M NaCl electrolyte solution. The sensing platform consists of Si wafer plasma bonded to a PDMS (poly-dimethyl siloxane) microchannel on top of the electrodes. For a constant applied voltage, the rate of decay of current with time is observed to be a function of the flow rate (flux of ions per unit time). As the flow rate increased, the ions available at the electrode surface increased per unit time leading to slower decay rates. The model equation for current-time curve was obtained as I = αe-(t/τ); where α = 0.0002 ± (1% of 0.0002) and τ = 0.312 to 0.797 for electrolyte (0.1 M NaCl) flow rates ranging from 0 to 200 μL/min. The sensitivity and 3σ resolution of the flow sensor are 0.10 sec/(μL/min)/mm2 and 3.64 μL/min respectively. This work models the coulometric current-time curve as a first order decay problem.

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Section: Fig 1: Principles Of Physics For Flow Rate Measurementmentioning

confidence: 99%

Modeling the coulometric data for on-chip flow rate detection as a first order decay problem in a microfluidic device

Deswal,

Pandey,

Singh

et al. 2024

Microfluidics, BioMEMS, and Medical Microsystems XXII

View full text Add to dashboard Cite

show abstract

“…Also, the fluids flowing inside microfluidic devices are an unknown entity to the end user and the device is prone to failure problems [6]. Therefore, it becomes critical to provide the end user with sufficient information about fluid (including pressure, flow rate, and viscosity) and the device to decide the accuracy of the results [10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

On-chip resistive microfluidic flow sensor with reduced analysis time using transient analysis

Deswal,

Kanaparthi,

Singh

et al. 2024

Preprint

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In the realm of microfluidics, a critical issue prevails: the majority of flow sensors are situated external to the microfluidic chip itself, resulting in an inherent deficiency of precise operational insights. Fields like drug development, concentration gradient generation, and proactive healthcare demand meticulous, dependable data for broader utilization. In our current work, we introduce a microfluidic flow sensor designed to gauge electrochemical resistance within a circuit comprising electrolytic fluid and inter-digitated electrodes. This sensor's design features a Si wafer substrate housing micropatterned Ti/Pt electrode seamlessly bonded to a polydimethylsiloxane microchannel using oxygen plasma. What sets this innovation apart is the placement of microelectrodes within the microchannel, enabling on-chip flow rate measurements. Employing aqueous NaCl with variable solute concentrations ranging from 0.1 M to 0.4 M, we optimized the microchannel dimensions to accommodate flow rates spanning 0-500 µL/min. The sensor achieves a limit of detection (LOD) at 1 µL/min and boasts a resolution of 5 µL/min for lower flow rates (0 to 100 µL/min), while maintaining a resolution of 100 µL/min for higher flow rates (100 to 500 µL/min). Moreover, we have implemented an algorithm based on the trapezoidal rule, enabling flow rate prediction within 5 seconds. With its capability to swiftly and accurately measure flow rates across a wide spectrum, this proposed device emerges as an invaluable tool for applications mandating continuous flow rate monitoring.

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On-chip resistive microfluidic flow sensor with reduced analysis time using transient analysis

Deswal,

Kanaparthi,

Singh

et al. 2024

Exp Fluids

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Fluid Temperature Measurement in Aqueous Solution via Electrochemical Impedance

Cited by 6 publications

References 43 publications

Modeling the coulometric data for on-chip flow rate detection as a first order decay problem in a microfluidic device

Modeling the coulometric data for on-chip flow rate detection as a first order decay problem in a microfluidic device

On-chip resistive microfluidic flow sensor with reduced analysis time using transient analysis

On-chip resistive microfluidic flow sensor with reduced analysis time using transient analysis

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