Smartphone-based sensing system using ZnO and graphene modified electrodes for VOCs detection

Liu, Lei; Zhang, Diming; Zhang, Qian; Chen, Xing; Xu, Gang; Lu, Yanli; Liu, Qingjun

doi:10.1016/j.bios.2016.09.084

Cited by 98 publications

(27 citation statements)

References 45 publications

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“…The concentration of 2-methylcyclopentanone was calculated in ppm using the following equation. 47 where C is the vapor concentration required, ρ is the density of the liquid (g mL –1 ), T is the temperature (K), V s is the volume of the liquid analyte (μL), M is the molecular weight of the liquid analyte (g mol –1 ), and V is the volume of the test chamber (L). All experiments were carried out at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO₂–Polymer Nanocomposites

Okechukwu¹,

Mavumengwana²,

Hümmelgen

et al. 2019

ACS Omega

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Polymer nanocomposite-based sensors were prepared using cellulose acetate (CA), carbon nanoparticles (CNPs), and manganese dioxide (MnO 2 ) nanorods to detect and to understand the sensing mechanism of 2-methylcyclopentanone vapor. A sensor with a mass ratio of 1:1.5:3 of MnO 2 /CNPs/CA as well as MnO 2 /CA and MnO 2 /CNP composite and MnO 2 sensors were prepared. The sensor with the three sensing materials combined exhibited an enhancement of response for 2-methylcyclopentanone vapor, ascribed to a synergistic effect between MnO 2 /CNPs/CA. An in situ Fourier-transform infrared (FTIR)-combined online LCR meter setup was used to understand the sensing mechanism of the sensor. The sensing mechanism involved a deep oxidation decomposition of the analyte to CO 2 . This was confirmed from the in situ FTIR-combined online LCR meter results, where a new distinct CO 2 bending mode IR band was recorded. To optimize the performance of the sensor, the composites were prepared by varying the amount of metal oxide added into the composites; sensor A (composition of mass ratio 1:1.5:3), sensor B (composition of mass ratio 2:1.5:3), and sensor C (composition of mass ratio 2.5:1.5:3); their compositions are MnO 2 /CNPs/CA. The performance of sensor B was higher than that of the other two sensors. The sensors also show relatively good response–recovery time. All fabricated sensors were found to have the sensing ability regenerated after the analyte was removed from the system without losing its sensing and recovery abilities. The structural and morphological features of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy.

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Section: Methodsmentioning

confidence: 99%

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO₂–Polymer Nanocomposites

Okechukwu¹,

Mavumengwana²,

Hümmelgen

et al. 2019

ACS Omega

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“…Recently more and more peripherals have begun using Bluetooth to wirelessly transmit data to and from the smartphone, as seen in the examples in Figure . The obvious benefit is that these types of peripherals are compatible with all types of smartphones regardless of the make or model.…”

Section: Integration With Smartphonementioning

confidence: 99%

“…Hence, most of the PoC oriented EIS sensors require power sources such as a 9 V lithium ion battery. As is true with the other two measurement modes, there exists a popular commercial IC solution, AD5933 , which is able to fit a complete digital signal generator (DDS) core, DAC, ADC, and discrete Fourier transform (DFT) hardware into a single small chip as is shown in Figure (A) . However, the main issues with this IC are that the smallest potential stimulus it can apply is ∼200 mV peak‐to‐peak and the bias point cannot be set independently of the amplitude.…”

Section: Poc Implementations Of E‐chem Techniquesmentioning

confidence: 99%

Point‐of‐Care Smartphone‐based Electrochemical Biosensing

Sun

Hall

2018

Electroanalysis

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Point‐of‐care (PoC) biosensors offer promising solutions to today's adverse and costly healthcare issues by moving diagnostic tools closer to the patient. The ubiquity of smartphones has brought about an emergence of PoC devices, which leverage the smartphone's capabilities, enabling the creation of low‐cost and portable biosensors. Electrochemical biosensors are well suited for PoC testing since the transducers can be miniaturized and inexpensively fabricated. This review paper discusses recent developments in smartphone‐based electrochemical biosensors for PoC diagnostics. These peripherals utilize the various connectivity options (for example proprietary ports, audio headphone‐jack, or wireless radio) to offload functionality to the smartphone. The smartphone‐based implementations of various electrochemical techniques, such as amperometry, potentiometry, and impedance spectroscopy are explored. Major challenges include reducing power, area, and cost of measurement circuitry, while maintaining adequate performance for PoC diagnostic applications.

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“…The merits of smartphones brought new possibilities for biomedical and biosensor research. Recently, many studies on smartphone-controlled platforms at the point of care (POC) have been published and several electrochemical methods have been combined with smartphone for quantitative electrochemical detections, such as chronoamperometry (CA), cyclic voltammetry (CV), differential pulse voltammetry (DPV) [13,14] and electrochemical impedance spectroscopy (EIS) [14][15][16][17]. Among them, DPV is capable of detection of low-level concentrations of analytes.…”

Section: Introductionmentioning

confidence: 99%

Salivary Cortisol Determination on Smartphone-Based Differential Pulse Voltammetry System

Liu

Men

et al. 2020

Sensors

Self Cite

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Cortisol is commonly used as a significant biomarker of psychological or physical stress. With the accelerated pace of life, non-invasive cortisol detection at the point of care (POC) is in high demand for personal health monitoring. In this paper, an ultrasensitive immunosensor using gold nanoparticles/molybdenum disulfide/gold nanoparticles (AuNPs/MoS2/AuNPs) as transducer was explored for non-invasive salivary cortisol monitoring at POC with the miniaturized differential pulse voltammetry (DPV) system based on a smartphone. Covalent binding of cortisol antibody (CORT-Ab) onto the AuNPs/MoS2/AuNPs transducer was achieved through the self-assembled monolayer of specially designed polyethylene glycol (PEG, SH-PEG-COOH). Non-specific binding was avoided by passivating the surface with ethanolamine. The miniaturized portable DPV system was utilized for human salivary cortisol detection. A series current response of different cortisol concentrations decreased and exhibited a linear range of 0.5–200 nM, the detection limit of 0.11 nM, and high sensitivity of 30 μA M−1 with a regression coefficient of 0.9947. Cortisol was also distinguished successfully from the other substances in saliva. The recovery ratio of spiked human salivary cortisol and the variation of salivary cortisol level during one day indicated the practicability of the immunosensor based on the portable system. The results demonstrated the excellent performance of the smartphone-based immunosensor system and its great potential application for non-invasive human salivary cortisol detection at POC.

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Smartphone-based sensing system using ZnO and graphene modified electrodes for VOCs detection

Cited by 98 publications

References 45 publications

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO₂–Polymer Nanocomposites

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO₂–Polymer Nanocomposites

Point‐of‐Care Smartphone‐based Electrochemical Biosensing

Salivary Cortisol Determination on Smartphone-Based Differential Pulse Voltammetry System

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Smartphone-based sensing system using ZnO and graphene modified electrodes for VOCs detection

Cited by 98 publications

References 45 publications

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO2–Polymer Nanocomposites

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO2–Polymer Nanocomposites

Point‐of‐Care Smartphone‐based Electrochemical Biosensing

Salivary Cortisol Determination on Smartphone-Based Differential Pulse Voltammetry System

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Product

Resources

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Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO₂–Polymer Nanocomposites

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO₂–Polymer Nanocomposites