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Detection of volatile organic compounds by weight-detectable sensors coated with metal-organic frameworks.

Yamagiwa H, Sato S, Fukawa T, Ikehara T, Maeda R, Mihara T, Kimura M - Sci Rep (2014)

Bottom Line: Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper.The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors.Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan.

ABSTRACT
Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

No MeSH data available.


Related in: MedlinePlus

a) Responses of QCM sensors modified with Cu3(BTC)2 exposure to 100 ppm toluene vapor at 20 (), 30 (), 40 (), and 60°C (). Dotted line is a response of QCM sensor without Cu3(BTC)2 exposure to 100 ppm toluene vapor at 60°C. b) Frequency change versus toluene concentration at 60°C.
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f2: a) Responses of QCM sensors modified with Cu3(BTC)2 exposure to 100 ppm toluene vapor at 20 (), 30 (), 40 (), and 60°C (). Dotted line is a response of QCM sensor without Cu3(BTC)2 exposure to 100 ppm toluene vapor at 60°C. b) Frequency change versus toluene concentration at 60°C.

Mentions: Figure 2a shows the time course of the sensor responses (ΔF) of the QCMs coated with Cu3(BTC)2 responding to exposure to a 100 ppm toluene vapor at 20, 30, 40 and 60°C. The frequency of the QCM operated at 60°C rapidly decreased in response to the toluene vapor exposure, and the signal stayed constant at −ΔF = 3000 Hz after equilibrium was achieved. When the carrier gas changed to pure nitrogen gas, the frequency returned to the initial state within 5 min, which indicates reversible adsorption/desorption processes of toluene. The sensor exhibited a good repeatability for toluene sensing (Fig. S5). Although the maximum responses for a 100 ppm toluene vapor increased with decreasing operation temperature, the desorption process was slower than that at 60°C. The concentration-dependent responses to the toluene vapor are shown in Figure 2b. The response appeared to increase linearly in the concentration range of 0–100 ppm and saturated above 100 ppm, which was followed by the Langmuir sorption model based on the presence of a set number of nanospaces within the Cu3(BTC)2 layer. A concentration increase of 10 ppm in toluene vapor causes a frequency shift of 90 Hz for the QCM sensor with the Cu3(BTC)2 layer. The detection limit for the QCM sensor with the Cu3(BTC)2 layer was evaluated by a concentration change leading to a signal meeting the signal-to-noise ration conventions of the IUPAC (S/N: 3/1)34. We found that the detection limit for toluene was about 1 ppm (a noise level is ±1.5 Hz). This detection limit for the Cu3(BTC)2 layer is good compared to our previously reported values for polymer and nanoparticle-based sensing layers891011, suggesting that the porous MOF layers play an effective concentrator for the VOC vapors on weight-detectable sensors.


Detection of volatile organic compounds by weight-detectable sensors coated with metal-organic frameworks.

Yamagiwa H, Sato S, Fukawa T, Ikehara T, Maeda R, Mihara T, Kimura M - Sci Rep (2014)

a) Responses of QCM sensors modified with Cu3(BTC)2 exposure to 100 ppm toluene vapor at 20 (), 30 (), 40 (), and 60°C (). Dotted line is a response of QCM sensor without Cu3(BTC)2 exposure to 100 ppm toluene vapor at 60°C. b) Frequency change versus toluene concentration at 60°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150105&req=5

f2: a) Responses of QCM sensors modified with Cu3(BTC)2 exposure to 100 ppm toluene vapor at 20 (), 30 (), 40 (), and 60°C (). Dotted line is a response of QCM sensor without Cu3(BTC)2 exposure to 100 ppm toluene vapor at 60°C. b) Frequency change versus toluene concentration at 60°C.
Mentions: Figure 2a shows the time course of the sensor responses (ΔF) of the QCMs coated with Cu3(BTC)2 responding to exposure to a 100 ppm toluene vapor at 20, 30, 40 and 60°C. The frequency of the QCM operated at 60°C rapidly decreased in response to the toluene vapor exposure, and the signal stayed constant at −ΔF = 3000 Hz after equilibrium was achieved. When the carrier gas changed to pure nitrogen gas, the frequency returned to the initial state within 5 min, which indicates reversible adsorption/desorption processes of toluene. The sensor exhibited a good repeatability for toluene sensing (Fig. S5). Although the maximum responses for a 100 ppm toluene vapor increased with decreasing operation temperature, the desorption process was slower than that at 60°C. The concentration-dependent responses to the toluene vapor are shown in Figure 2b. The response appeared to increase linearly in the concentration range of 0–100 ppm and saturated above 100 ppm, which was followed by the Langmuir sorption model based on the presence of a set number of nanospaces within the Cu3(BTC)2 layer. A concentration increase of 10 ppm in toluene vapor causes a frequency shift of 90 Hz for the QCM sensor with the Cu3(BTC)2 layer. The detection limit for the QCM sensor with the Cu3(BTC)2 layer was evaluated by a concentration change leading to a signal meeting the signal-to-noise ration conventions of the IUPAC (S/N: 3/1)34. We found that the detection limit for toluene was about 1 ppm (a noise level is ±1.5 Hz). This detection limit for the Cu3(BTC)2 layer is good compared to our previously reported values for polymer and nanoparticle-based sensing layers891011, suggesting that the porous MOF layers play an effective concentrator for the VOC vapors on weight-detectable sensors.

Bottom Line: Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper.The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors.Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan.

ABSTRACT
Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

No MeSH data available.


Related in: MedlinePlus