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MOF-based Sensors for Volatile Organic Compounds
Published in Ram K. Gupta, Tahir Rasheed, Tuan Anh Nguyen, Muhammad Bilal, Metal-Organic Frameworks-Based Hybrid Materials for Environmental Sensing and Monitoring, 2022
Shuvendu Tripathy, Santimoy Khilari
Thus, QCR sensors determine the change in the mass per unit area by measuring the variation in their oscillatory frequency. Here, the physicochemical property of the MOF (for example, specific surface area) plays an important part in the detection of the analyte. The major advantages of the QCM-based sensing technique are simple, low cost, operate at room temperature, have a rapid response time, and have excellent sensitivity.
Mechanical Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
The quartz crystal microbalance (QCM) is a mass-sensing device capable of measuring mass changes in the nanogram range (Kanazawa and Cho 2009). It is basically a quartz crystal resonator with the ability to measure very small mass changes in real time.
Bio-Nanoparticles: Nanoscale Probes for Nanoscale Pathogens
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Mohamed S. Draz, Yiwei Tang, Pengfei Zhang
QCM is a simple, cost-effective, high-resolution mass-sensing technique. The core part of the QCM is the piezoelectric AT-cut quartz crystal sandwiched between a pair of electrodes. When the electrodes are connected to an oscillator and an AC voltage is applied over the electrodes, the quartz crystal starts to oscillate at its resonance frequency due to the piezoelectric effect [28,191,192]. QCM sensors modified with gold nanoparticle–DNA conjugates were applied for the detection of DENV type 1 (DENV-1) (Table 20.3). Gold nanoparticles have a definite mass and relatively large surface area for conjugation and molecular interaction, and when integrated with QCM, gold nanoparticles act as effective mass amplifiers to enhance the detection sensitivity. In this system, the QCM works as a highly sensitive transducer for the mass increase of the DNA-modified quartz crystal upon DNA hybridization, and gold nanoparticles were applied as a signal amplifier (Figure 20.6) [28].
Recent advances in the synthesis of and sensing applications for metal-organic framework-molecularly imprinted polymer (MOF-MIP) composites
Published in Critical Reviews in Environmental Science and Technology, 2023
Yongbiao Hua, Deepak Kukkar, Richard J. C. Brown, Ki-Hyun Kim
QCM is a mass sensing technique that can sense nanogram levels of the target analytes by measuring variations in the oscillating frequency when target analytes are loaded onto the surface of a resonator (Malik et al., 2019). On the basis of mass change, QCM is well suited as a transducer element for the fabrication of sensors because of its rapid response, simple operation, highly stable signal, and portability (Emir Diltemiz et al., 2017). To improve selectivity toward the target species, MIPs with high intrinsic selectivity are combined with QCM techniques, which enables outstanding recognition of imprinted polymeric receptors and efficient gravimetric transduction for the trace-level, real-time detection of target analytes (Mujahid et al., 2018). Recently, a UiO-66 immobilized MIP–based QCM sensor was proposed for the specific and sensitive determination of tyramine (Yao et al., 2020). The high specific surface area of UiO-66 provided many imprinted sites for tyramine recognition with the aid of tailor-made MIPs. On the basis of the frequency response (Δƒ) of QCM against tyramine concentrations, a good linear relationship was obtained between the frequency change and tyramine concentration across a range of 583–3640 nM (Figure S4(C)). This UiO-66@MIP-based QCM sensor exhibited an LOD of 4.49 × 105 pM for sensing tyramine (Yao et al., 2020).
An approach to compare performance of surgical masks for fighting against the COVID-19 pandemic
Published in Aerosol Science and Technology, 2022
QCM is a mass sensitive technique that can measure mass changes on the sensor surface at nano gram sensitivity. In this technique, mass on the sensor is measured in real time, thus allowing close monitoring of changes such as mass increase or decrease on the sensor surface (Lu, Czanderna, and Townshend 1987). More information is given in the Supporting Information. The schematic diagram of the PLL based QCM system and block diagram of QCM controller are given in Figure 2a and 2b, respectively. Experimental test setup is given in Figure 2c. QCM uses a AT-cut quartz sensor that vibrates at its own resonant frequency, and the resonant frequency of the sensor is monitored by a PLL (Phase-Locked Loop). PLL-based piezoelectric sensor was developed for the first time by Hu et al. (2016). The temperature stability of the system is very important. Due to the properties of quartz, the resonance frequency of the QCM crystals depends on the temperature (Bradshaw 2000; Sauerbrey 1959). The room temperature and sensor temperature was kept at 22 °C during the experiments. Laboratory relative humidity (RH) level was measured 34%. The PLL-based QCM controller includes a high-bandwidth locked amplifier (LIA) to measure the sensor vibration amplitude and phase. There are two PID based feedback control systems to lock the phase and amplitude of the sensor signal. The phase lock feedback loop generates frequency shift data and the amplitude feedback loop produces a signal that can be correlated with the mechanical properties of the thin film on the sensor.
Mass loading induced frequency shift of a thickness-shear vibrating quartz crystal plate considering size effect based on the modified couple stress theory
Published in Mechanics of Advanced Materials and Structures, 2020
Xuan Xie, Jiemin Xie, Shan Jiang, Jian Lei
The quartz crystal plate with thickness shear vibration mode (TSM) [1] is widely used as a high sensitivity sensor to sense the surface substance, such as coatings [2], liquid [3], film-liquid layers [4–6] or micro/nano structures [7–9]. This kind of quartz crystal resonator (QCR) based sensor is also called quartz crystal microbalance (QCM). In order to achieve high sensitivity, the quartz crystal plate is usually made very thin to improve fundamental frequency. For example, a typical QCM with a fundamental frequency of 10 MHz is only 165 μm thick [10]. Nowadays ultrahigh fundamental frequency (35 ∼ 65MHz) QCMs (25 ∼ 50μm thick) gradually come into application [11–13]. On the other hand, the novel or unusual mechanical behavior of micro sized structures has been often observed by many researcher (e.g., Lam et al. [14]; McFarland and Colton [15]). Various nonlocal theories such as nonlocal elasticity theory [16], modified strain gradient theory [14] and modified couple stress theory [17–20] have been widely accepted as an alternative to account for the size effects of these micro-structures. In recent years, the mode of size dependent linear piezoelectric material based on the modified couple stress theory has been established and used by many researchers [21–24].