| Antibiotic sensor refers to a sensor that uses antibiotic action substances and signal input-output devices to measure the content of antibiotics.The content of antibiotics usually reflects the level of resistance growth of bacteria and viruses in the hydrological environment.The existence of excessive antibiotics in the hydrological environment will lead to an increasingly serious threat to the survival of life by bacteria and viruses.Therefore,the detection of antibiotics in the hydrological environment is of great significance for the early warning of life and disease prevention.In recent years,a variety of detection methods have been reported,but these methods usually contain various defects,such as detection limits,short linear detection ranges,or special detection conditions.Therefore,it is an important challenge for researchers that to develop sensing methods which can be used for actual sample detection.Among these methods,the photoelectrochemical（PEC）antibiotic sensing detection technology has attracted attention because of its low instrument price,simple operation,fast analysis speed,and good analytical performance.PEC refers to the energy conversion based on photoelectricity or electroluminescence,through the chemical reaction between substances to form bonds to achieve the impact on energy.This effect will cause the change of photocurrent macroscopically,and the signal variation has a linear relationship with the content of the target molecule.Consider the difference approach between the energy input and output,this method has strong anti-interference performance,while taking into account extremely low detection limits and strong sensitivity,and has strong application advantages.This thesis uses water-soluble zinc selenide quantum dots（Zn Se QDs）with semiconductor properties as photoelectric active materials to construct MIP/Zn Se/EDC@NHS/GCB@MWNTs/FTO and Et OH/Zn Se@Ti O2/DNL-6/CNH@CNTs/GCE PEC sensors respectively.The content of antibiotics was measured as follows:（1）MIP/ZnSe/EDC@NHS/GCB@MWNTs/FTO PEC sensor detects norfloxacin（NFX）.Through a simple and mature preparation method,Zn Se QDs modified with mercaptopropionic acid（3-MPA）were successfully synthesized,and modified on a glassy carbon electrode to construct a MIP/Zn Se/EDC@NHS/GCB@MWNTs/FTO sensor,and the sensor has been applied to NFX detection successfully.The preparation conditions of the prepared sensor were optimized,and the performance of the sensor was characterized and the mechanism of NFX detecting was explored.The sensor can form hydrogen bonds between NFX and pyrrole（PYR）to immobilize NFX at the electrode surface holes,thereby enhancing the photocurrent signal for accurate determination of NFX concentration.The composite of glassy carbon spheres and multi-walled carbon nanotubes（GCB@MWNTs）not only has a high specific surface area to carry a large amount of Zn Se QDs,but also can enhance the photocurrent transmission capability of the sensor.The linear detection range of the NFX sensor in 0.2 M p H 9.5 phosphate buffer solution（PBS）containing 0.1 M potassium chloride（KCl）and 8 m M tri-n-propylamine（TPr A）was tested as 1×10-10-1×10-4 M,the detection limit reached 3.3×10-11 M.The actual sample of NFX was verified,and it was confirmed that the sensor has high precision and good selectivity.（2）EtOH/ZnSe@TiO2/DNL-6/CNH@CNTs/GCE PEC sensor detects clindamycin（CLI）.By using the DNL-6 molecular sieve,Zn Se QDs and titanium dioxide composite（Zn Se@Ti O2）nanocomposite materials and carbon nanohorns and ordered carbon nanotubes（CNH@CNTs）separately,we constructed Et OH/Zn Se@Ti O2/DNL-6/CNH@CNTs/GCE sensor through layer-by-layer assembly.And it has a quenching response ability to CLI.The amidation reaction formed between CLI and Zn Se,due to its insoluble properties hinders the photoelectric signal transmission of Zn Se QDs,thereby realizing signal quenching and successfully constructing an accurate detection method for CLI content.CNH@CNTs has the ability to carry materials on the electrode surface and conduct electricity efficiently.DNL-6 was used as a photoelectric conversion platform to achieve uniform distribution of Zn Se QDs and enhance the stability of antibiotic sensor signals.Ethanol（Et OH）plays a role in Zn Se and DNL as the catalysis of ester-forming condensation between Zn Se and DNL-6,which enhances the transmission capacity of photocurrent.The linear detection range of the sensor for CLI was 5×10-11 M-5×10-4M,and the detection limit achieved 1×10-11 M.Finally,a new CLI measurement method was developed for actual sample detection successfully. |
PDF Full Text Request