| With the increasing demands of automation and intellectualization,sensor technology,which is the main mean of obtaining information from the outside world has attracted the attention of researchers all over the world.Quartz crystal microbalance(QCM)is a resonant mass sensor based on the piezoelectric effect with the detection accuarcy of nanogram.By modifying sensitive material as sensing film on the quartz disc,QCM can be used as a gas sensor or a biosensor which can be applied in the fields of environmental monitoring,food industry,medical inspection and public safety However,traditional QCM sensors are limited by their "sandwich" structure and positive feedback excitation working way,which limits their working frequency,available resonant parameters and applicationsIn this thesis,instead of using the stimulation and detection method of the traditional QCM,the form of electromagnetic stimulation and detection was adopted.so as to overcome the defects of traditional QCM sensors.A wireless-eletrodeless QCM with dissipation system(WE-QCM-D)was developed,which was better in the sensing performance than traditional QCM.Combined with the gas detection and biochemical detection technique,gas sensors and biosensors with higher working frequency,more available parameters and more flexible applications were developed based on the WE-QCM-D system.The main contents and results of this thesis were as follow sWith the form of electromagnetic emission and reception,the wireless excitation and detection of quartz disc was realized.Based on this,the hardw are and the circuit of the WE-QCM-D system was designed and developed.The automatic and continuous acquisition of the data and the calculation of the resonant parameters were realized through the software platform based on Labview.Finally,the gas phase and the liquid phase detection chambers were designed and both the detection platforms for WE-QCM-D were builtNano-Ni(OH)2.was synthesized and coated to quartz disc as the sensitive film to develop a dibutyl phthalate(DBP)sensor.Under the condition of room temperature and fundamental frequency,the DBP sensor based on WE-QCM-D is consistent with the DBP sensor based on the traditional QCM.The ppb level DBP detection was realized and good repeatability,selectivity with better stability and signal to noise ratio was also achieved.In addition,WE-QCM-D can increase the working frequency through the excitation of higher overtone.With the same quartz disc and sensing film,higher sensitivity and lower detection limit for DBP detection were achievedNanosized In2O3 microspheres were synthesized and doped with gold nanoparticles.and ln2O3-Au microspheres were obtained.Both materials were respectively used to modify quartz discs,and a WE-QCM-D dimethyl methylphosphonate(DMMP)sensor was made.In the experiment,the thickness of the sensitive films were optimized,the sensitivity and selectivity of the sensors were also tested.The results showed that the sensitivity of the In2O3-Au film coated sensor was 4 times higher than the undoped film based one,and the selectivity of the sensor coated with the In2O3-Au film was also improved.By doping the In2O3 film with noble metal,better sensing performance was achieved.In addition,the relationship betw een frequency and dissipation was further analyze and the mechanism of the overshoot in desorption process was deduced.The results showed that the WE-QCM-D system could provide useful stratage in the dynamic analyysis of the detection obj ectsThe mechanism of reversible binding between boric acid and carbohydrates was known for a long time.Based of this.poly(acrylamide-co-3-acrylamideophenylboronic acid)based hydrogel film was successfully polymerized on quartz dise,and a noninvasive,non-enzme glucose sensor based on the WE-QCM-D was developed.To suppress the response to fructose.(3-acrylamidopropyl)tri-methylammonium chloride cation was added to the sensitive film.neutralizing the negative charge of the 1:1 binding of boric acid and fructose,and promoting the 1:2 binding of boric acid and glucose,thus improving the selectivity of the sensing film.In the experiment,the formulation of the sensitive film was optimized.and the sensitivity.selectivity and repeatability of the sensor were tested.At 37?.the sensor can achieve continuous.accurate and rapid detection of glucose within the physiological concentration range(3.3-6.1mM).It is believed that the WE-QCM-D system has the potential to achieve non-invasive continuous biochemical parameters monitoring in vivo. |
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