A Quartz Crystal Microbalance Aptamer Sensor For Tetracycline Detection In Food Based On Gold Nanoparticles And MOFs

Tetracycline is a widely used tetracycline antibiotic.As a kind of feed additive in animal breeding,tetracycline is used to prevent and cure diseases and promote the growth of animals.Because of the irrational use of tetracycline,it remains in animals and enters the human body through the food chain,which affects people's health.At present,the test method of tetracycline aiming at residue in the food has been reported frequently.Because the traditional test method has the disadvantages of expensive equipment and instrument,low sensitivity and difficulty in real-time detection.Therefore,it is necessary to establish a low cost,simple operation,high sensitivity and stable and reliable method to detect tetracycline residue in food.Quartz crystal microbalance has the advantages of low cost,high sensitivity and real-time online detection.Gold nanoparticles can combine with biological macro-molecules without changing their activity and high conductivity.Metal organic framework materials(metal organic frameworks,MOFs)have high porosity and large specific surface area.The aptamers have the advantages of high specificity,high affinity,easy synthesis,good stability and wide range of targets.The experiment established a quartz crystal microbalance aptamer sensor based on gold nanoparticles and MOFs which is used to realize the rapid,high sensitivity and high selectivity detection of tetracycline.Meanwhile,it can test tetracycline in milk.Concrete content is as following:First,preprocess Quartz Auelectrode(QAu E)and modify HKUST-1 on the surface of the treated electrode by drop-coating.Then,gold nanoparticles were modified by electrodeposition.The aptamer with sulfhydryl group is fixed to the surface of the modified electrode by Au-S bond.The sensing interface of quartz crystal microbalance aptamer sensor was constructed by sealing the modified electrode surface with 6-mercaptohexanol.Characterization of sensor's constructing process is adopted methods of cyclic voltammetry,differential pulse voltammetry and scanning electron microscope.The conditions affecting the detection performance of quartz crystal microbalance aptamer sensor including aptamer modification concentration,incubation time between aptamer and electrode,phosphate buffer solution p H were optimized.The experimental results showed that the optimal concentration of aptamer modification was 0.6 ?mol/L,the optimal incubation time between aptamer and electrode was 60 min,and the optimal p H of phosphate buffer solution was 7.0.The performance of the constructed tetracycline quartz crystal microbalance aptamer sensor is evaluated,including the establishment of standard curve,selectivity,anti-interference ability,reproducibility and stability of the constructed sensor.Experimental results show that the linear relationship between the frequency variation of the quartz crystal microbalance aptamer sensor and the logarithmic value of tetracycline concentration is from 1×10-10 g/m L to 1×10-5 g/m L.The correlation between them is 0.979,and the low detection limit of 0.8×10-11 g/m L.Besides,the sensor has good selectivity,anti-interference ability,good reproducibility and stability.Tetracycline in milk samples was detected by the method of recovery,and good results were obtained.The recovery rate was 85.3%~91.4%.