| Potential chemical contaminants in food are serious threats to human health.Complex matrices in food sample can interfere with the analysis of trace chemical contaminants.Therefore,it is of great significance to develop highly selective,fast and sensitive sensing methods.Solid-state nanochannel technology based on spatial confinement effect has received extensive attention as a promising analytical detection technology due to its high sensitivity,but related research is still less.Therefore,this dissertation aims to design and construct novel functionalized anodized aluminum oxide（AAO）nanochannels sensors with ultra-large channel density for efficient and accurate analysis of typical chemical contaminants in food.The main works carried out are as follows:A nanochannel detection system was built.The laboratory-built nanochannel system includes a homemade flow cell,2450 digital Source Meter/patch clamp amplifier,signal shielding box,Ag/Ag Cl electrodes and data acquisition/analysis system.The flow cell was designed with the aid of Auto CAD and its size was optimized for practical application.3 nm nanopores in Si3N4 membrane were successfully prepared and enabled the effective acquisition and analysis of the current signal produced by the flow through of the single aptamer molecule.The amplitude and dwell time of the current signals are in a normal distribution.The steady-state current of functionalized nanochannels showed good stability.The developed nanochannel detection system lays the foundation for the subsequent studies on the detection typical hazardous substances in food based on solid-state nanochannels,and provides a powerful platform for the laboratory to carry out other research in the field of food safety in the future.An aptamer self-assembly（AAs）-functionalized nanochannel sensor was developed for highly sensitive determination of chloramphenicol（CAP）in food samples.To realize the detection of trace CAP in complex food systems,CAP-specific AAO nanochannels functionalized with AAs（AAs@AAO）were designed and fabricated.When CAP is present,CAP interacts with AAs to change the surface charge of AAs@AAO.Accordingly,a new method for the detection of CAP based on AAs@AAO was developed,with a linear range of 0.32-1600 pg mL-1,a limit of detection（LOD 3s）of 0.1 pg mL-1,and a relative standard deviation of 2.9%for 11replicate determinations of 32.3 pg mL-1 CAP.The developed method allows accurate detection of CAP,even in the presence of several common interferants such as thiamphenicol,florfenicol,kanamycin and gentamicin.The proposed method was successfully applied for the determination of CAP in milk,milk powder and honey samples with the recoveries of 93.4%-102.2%.The AAs functionalized nanochannel is expected to become a simple,sensitive and precise universal sensor for the detection of other analytes by changing the type of aptamer.A two-dimensional covalent organic framework（2D COF）functionalized AAO sensor was fabricated for the rapid and accurate detection of mercury in food.The slow interaction between recognition group and target makes the detection time of the nanochannel sensor greatly increase,so accelerating the kinetics of the recognition group and the target is the key to the development of rapid detection methods based on nanochannels.The ordered channels of 2D COF endow COF with the fast mass transfer efficiency of the analyte,so the irreversible thiourea 2D COF（JNU-3）functionalized nanochannel sensor（JNU-3@AAO）was prepared.In the presence of Hg（Ⅱ）,the thiourea group of JNU-3 can selectively interact with Hg（Ⅱ）,changing the surface charge of JNU-3@AAO and realizing the specific detection of Hg（Ⅱ）.Due to the highly ordered channel of JNU-3,stable signal can be obtained in in only 90 s.The developed method gave a LOD（3s）of 3.28 fg mL-1,and an RSD of 3.8%for 11replicate determinations of Hg（Ⅱ）at 10 pg mL-1.The recoveries of spiked Hg（Ⅱ）in tap water,river water,lake water,and rice samples were 90.4%-99.8%.This work demonstrates the great potential of 2D COF functionalized nanochannel for rapid and precise detection of typical contaminants in food. |
