Surface Acoustic Wave DMMP Gas Sensor with a Porous Graphene/PVDF Molecularly Imprinted Sensing Membrane.
Ontology highlight
ABSTRACT:
SUBMITTER: Xu S
PROVIDER: S-EPMC8152042 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A highly sensitive and selective Raman sensor has been developed by combining molecularly imprinted cavities, silver nanoparticles, and graphene oxide into a hybrid organic-inorganic film. The molecular imprinted nanocomposite material is an advanced platform that exhibits Graphene-mediated Surface-Enhanced Raman Scattering. The sensing layers have been prepared via sol-gel process and imprinted with rhodamine 6G to obtain selective dye recognition. Graphene oxide sheets decorated with silver nanoparticles have been incorporated into the matrix to enhance the Raman scattering signal. The template molecule can be easily removed from the films by ultrasonication in ethanol. A 712-fold Raman enhancement has been observed, which corresponds to a 2.15 × 1013 count·?mol-1 signal enhancement per molecular cavity. Besides Raman enhancement, the sensing platform has shown an excellent selectivity toward the test molecule with respect to similar dyes. In addition, the material can be reused at least 10 times without any loss of performance.
| S-EPMC6163847 | biostudies-other
Project description:A microfluidic film bulk acoustic wave resonator gas sensor (mFBAR) adapted specifically as an in-line detector in gas chromatography was described. This miniaturized vapor sensor was a non-destructive detector with very low dead volume (0.02 μL). It was prepared by enclosing the resonator in a microfluidic channel on a chip with dimensions of only 15 mm × 15 mm × 1 mm. The device with polymer coating showed satisfactory performance in the detection of organophosphorus compound, demonstrating a very low detection limit (a dozen parts per billion) with relatively short response time (about fifteen seconds) toward the simulant of chemical warfare agent, dimethyl methylphosphonate. The in-line detection of the mFBAR sensor with FID was constructed and employed to directly measure the concentration profile on the solid surface by the mFBAR with the controlled concentration profile in the mobile phase at the same time. The difference of peak-maximum position between mobile phase and solid phase could be a convenient indicator to measure mass transfer rate. With the response of the mFBAR and FID obtained in one injection, an injection mass-independent parameter can be calculated and used to identify the analyte of interest.
| S-EPMC8540273 | biostudies-literature
Project description:To improve the quality of modern life in the current society, low-power, highly sensitive, and reliable healthcare technology is necessary to monitor human health in real-time. In this study, we fabricated partially suspended monolayer graphene surface acoustic wave gas sensors (G-SAWs) with a love-mode wave to effectively detect ppt-level acetone gas molecules at room temperature. The sputtered SiO2 thin film on the surface of a black 36°YX-LiTaO3 (B-LT) substrate acted as a guiding layer, effectively reducing the noise and insertion loss. The G-SAWs exhibited enhanced gas response towards acetone gas molecules (800 ppt) in a real-time atmosphere. The high sensitivity of the G-SAW sensor can be attributed to the elasticity and surface roughness of the SiO2 film. In addition, the G-SAW sensor exhibited rapid response and recovery at room temperature. This study provides a potential strategy for diagnosing different stages of diabetes in the human body.
| S-EPMC10696977 | biostudies-literature
Project description:The development of a sensor based on molecularly imprinted polymer nanoparticles (nanoMIPs) and electrochemical impedance spectroscopy (EIS) for the detection of trace levels of cocaine is described in this paper. NanoMIPs for cocaine detection, synthesized using a solid phase, were applied as the sensing element. The nanoMIPs were first characterized by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering and found to be ~148.35 ± 24.69 nm in size, using TEM. The nanoMIPs were then covalently attached to gold screen-printed electrodes and a cocaine direct binding assay was developed and optimized, using EIS as the sensing principle. EIS was recorded at a potential of 0.12 V over the frequency range from 0.1 Hz to 50 kHz, with a modulation voltage of 10 mV. The nanoMIPs sensor was able to detect cocaine in a linear range between 100 pg mL-1 and 50 ng mL-1 (R2 = 0.984; p-value = 0.00001) and with a limit of detection of 0.24 ng mL-1 (0.70 nM). The sensor showed no cross-reactivity toward morphine and a negligible response toward levamisole after optimizing the sensor surface blocking and assay conditions. The developed sensor has the potential to offer a highly sensitive, portable and cost-effective method for cocaine detection.
| S-EPMC7146329 | biostudies-literature
Project description:A molecularly imprinted sol-gel is reported for selective and sensitive electrochemical determination of the drug naloxone (NLX). The sensor was developed by combining molecular imprinting and sol-gel techniques and electrochemically grafting the sol solution onto a functionalized multiwall carbon nanotube modified indium-tin oxide (ITO) electrode. The sol-gel layer was obtained from acid catalyzed hydrolysis and condensation of a solution composed of triethoxyphenylsilane (TEPS) and tetraethoxysilane (TES). The fabrication, structure and properties of the sensing material were characterized via scanning electron microscopy, spectroscopy and electrochemical techniques. Parameters affecting the sensor's performance were evaluated and optimized. A sensor fabricated under the optimized conditions responded linearly between 0.0 µM and 12 µM NLX, with a detection limit of 0.02 µM. The sensor also showed good run-to-run repeatability and batch-to-batch performance reproducibility with relative standard deviations (RSD) of 2.5-7.8% (n = 3) and 9.2% (n = 4), respectively. The developed sensor displayed excellent selectivity towards NLX compared to structurally similar compounds (codeine, fentanyl, naltrexone and noroxymorphone), and was successfully used to measure NLX in synthetic urine samples yielding recoveries greater than 88%.
| S-EPMC8001154 | biostudies-literature
Project description:The Growing demands for humidity detection in commercial and industrial applications led to the rapid development of humidity sensors based on different techniques. Surface acoustic wave (SAW) technology is one of these methods that has been found to provide a powerful platform for humidity sensing owing to its intrinsic features, including small size, high sensitivity, and simple operational mechanism. Similar to other techniques, the principle of humidity sensing in SAW devices is also realized by an overlaid sensitive film, which serves as the core element whose interaction with water molecules is responsible for overall performance. Therefore, most researchers are focused on exploring different sensing materials to achieve optimum performance characteristics. This article reviews sensing materials used to develop SAW humidity sensors and their responses based on theoretical aspects and experimental outcomes. Herein the influence of overlaid sensing film on the performance parameters of the SAW device, such as quality factor, signal amplitude, insertion loss, etc., is also highlighted. Lastly, a recommendation to minimize the significant change in device characteristics is presented, which we believe will be a good step for the future development of SAW humidity sensors.
| S-EPMC10222494 | biostudies-literature
Project description:The removal of radioiodine from the exhaust gas streams produced in spent fuel reprocessing plants is of paramount importance for the nuclear fuel cycle's security. Here, millimeter-sized poly(vinylidene fluoride) (PVDF) composites containing zirconium-based metal-organic frameworks, MOF-808, were synthesized by a facile phase inversion method to adsorb the volatile iodine. MOF-808@PVDF composites have inherited the crystallinity and pore accessibility of MOF-808, as well as its outstanding iodine capture performance. The MOF-808@PVDF composite beads containing 70 wt% MOFs, exhibited ultrahigh iodine adsorption capacity, 1.42 g g-1 at 80 °C, much higher than other millimeter-sized adsorbents reported in the literature. Raman mapping suggests that the negative iodine ions were formed at the early stage of iodine adsorption, while the close-packed iodine molecules were subsequently trapped in the frames. Using dynamic adsorption, the influences of iodine concentration, operating temperature and humidity were analyzed to evaluate its application potential in industrial conditions. The iodine adsorption capacity could reach 1.36 g g-1 at 80 °C, 100 °C and 120 °C in flow gas. And the elevated temperature (120 °C) is beneficial to accelerating the mass transfer of iodine vapor, as well as slightly inhibiting the competitive adsorption of water molecules under humidity. Besides, only one-third of the loaded iodine was released in nitrogen purging after saturated adsorption. The remaining majority was trapped firmly by the beads due to their strong interactions with the frameworks. This work highlights the millimeter-sized MOF-808@polymer composite beads with ultrahigh iodine adsorption capacity, providing experimental references for their application in radioiodine removal from hot and moist streams.
| S-EPMC9058509 | biostudies-literature
Project description:In recent years, finite element analysis is increasingly adopted to simulate the mechanism of metal oxide semiconductor (MOS) resistive gas sensors. In this article, the chemical reaction engineering module in the COMSOL Multiphysics tool is used to describe the dynamic equilibrium process of oxygen ions in the sensor. The boundary conditions of temperature transfer, conductivity model, and mass transfer are applied to simulate the convection, diffusion, and penetration processes. The response of the sensor at different temperatures (445 K-521 K) and different target gas concentrations (1-500 ppm) is simulated. In this paper, the dynamic model of oxygen ions is used creatively as a bridge between gas concentration and sensor response instead of the traditional direct parameter fitting method. The simulated result of the surface oxygen ion control and permeability control model of the MOS gas sensor shows a good agreement with the real sensor. For explaining the principle of metal oxide semiconductor gas sensors simulations has been performed on COMSOL Multiphysics software. The proposed method in this paper is based on the underlying transfer logic of the sensor signal, it is expected to predict the sensor signal and assist the sensor design.
| S-EPMC8387441 | biostudies-literature
Project description:We report ZnO/glass surface acoustic wave (SAW) humidity sensors with high sensitivity and fast response using graphene oxide sensing layer. The frequency shift of the sensors is exponentially correlated to the humidity change, induced mainly by mass loading effect rather than the complex impedance change of the sensing layer. The SAW sensors show high sensitivity at a broad humidity range from 0.5%RH to 85%RH with < 1 sec rise time. The simple design and excellent stability of our GO-based SAW humidity sensors, complemented with full humidity range measurement, highlights their potential in a wide range of applications.
| S-EPMC4244623 | biostudies-literature
Project description:In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro?polymerization in an aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples.
| S-EPMC6468396 | biostudies-literature