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The measurement of the concentration profile on the solid surface by the PEI-coated mFBAR with the controlled concentration profile in the mobile phase by FID at the same time. (a,b) Simulated analyte concentration profile in the mobile gas phase (top) and in the stationary phase (bottom) for the fast mass transfer (a) and slow mass transfer (b). K is the equilibrium constant; í µí° ¶ , í µí° ¶ , í µí° ¶ , í µí° ¶ , í µí° ¶ and í µí° ¶ are the analyte concentration on the solid surface and in the mobile phase, respectively. (c,d) The comparison of chromatogram from FID (top) with that from the PEI-coated mFBAR (bottom) at the different flow rates for analyte DMMP (c) and ethanol (d).
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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...
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... result demonstrated that the device is stable at ambient condition and the stability in sensor response is mainly dependent on the stability of sorption materials. Figure S4 shows the stability test of PEI-coated FBAR at ambient condition. We did not observe a significant change in response, indicating a good stability of PEI-polymer coating in nine months. ...
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... we compared the chromatogram of FID with the PEI-coated mFBAR. It should be noted that, through changing the coating material, the same procedure could be applied to analyze interaction of analytes with any other popular stationary phase materials such as OV-1, SE-30, etc. Figure 4a,b shows the simulated concentration profile of the two analytes in the mobile gas phase (top) and in the stationary phase (bottom) for the fast mass transfer and slow mass transfer. In the fast mass transfer, the peak maximums in the mobile phase and solid phase are located at the same position because of reaching equilibrium quickly. ...
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... the slow mass transfer, the peak maximums are far away from each other, where the equilibrium is not achieved. In Figure 4c, we show that the mass transfer of DMMP between the mobile gas phase and the solid surface reaches equilibrium quickly, thus giving the peak maximum at the closed position in the concentration profile when the flow rate is 1 mL min −1 . The flow rate appears to have an insignificant effect on the mass transfer between DMMP and PEI polymer since there is no significant difference of concentration profile from 1 mL min −1 to 7 mL min −1 . ...
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... flow rate appears to have an insignificant effect on the mass transfer between DMMP and PEI polymer since there is no significant difference of concentration profile from 1 mL min −1 to 7 mL min −1 . As can be seen in Figure 4c, the difference in peak position remains the same when the flow rate is 7 mL min −1 for DMMP. In comparison, shown in Figure 4d, the adsorption/desorption of ethanol between the mobile gas phase and the solid surface deviate significantly from the equilibrium due to a relatively slow mass transfer rate when the flow rate is 1 mL min −1 , giving the different peak maximum positions far away from each other. ...
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... can be seen in Figure 4c, the difference in peak position remains the same when the flow rate is 7 mL min −1 for DMMP. In comparison, shown in Figure 4d, the adsorption/desorption of ethanol between the mobile gas phase and the solid surface deviate significantly from the equilibrium due to a relatively slow mass transfer rate when the flow rate is 1 mL min −1 , giving the different peak maximum positions far away from each other. The flow rate appears to have a significant effect on the mass transfer between ethanol and PEI polymer. ...
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... Materials: The following are available online at www.mdpi.com/1424-8220/21/20/6800/s1, Figure S1: Fabrication process of mFBAR, Figure S2: GC-mFBAR-FID system set-up, Figure S3: Linearity of uncoated FBAR sensor for various vapors, Figure S4: Stability test of PEI-coated FBAR, Figure S5: Flow disturbance, Table S1: Variation value of peak maximum positions for the two vapors at the different flow rates, Figure S6: Response of mFBAR and FID for ethanol and DMMP, Table S2: The dependence of S value on the flow rates for ethanol and DMMP. 11 ...
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Fibrous composite materials provide distinct advantages in large surface area and enhanced molecular transport through the media, lending themselves to diverse applications. Despite substantial development in synthetic methods, it is still lacking in insights into structure–property relationships that can correlate features of the functional materi...
Citations
... Table 4 shows various coatings used with piezoelectric crystal detectors in gas chromatography. To enable in-line detection in gas chromatography, Hu et al. [119] developed a revolutionary microfluidic film bulk acoustic wave resonator gas sensor (mFBAR) in 2021, Figure 23a. The detecting element FBAR within this detector is contained within a microfluidic flow channel and operates via a desorption or adsorption mechanism. ...
... (a) mFBAR developed by Hu et al.[119]; (b) 1-dimensional separation of the chromatogram for 11 gases[119]. ...
... (a) mFBAR developed by Hu et al.[119]; (b) 1-dimensional separation of the chromatogram for 11 gases[119]. ...
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