Study On Antibiotics Detection Method Based On Optical Properties Of Gold Nanoclusters

With the increasingly serious pollution of water resources in China,people are increasingly concerned about pollutants in water.Among them,antibiotics are one of the important pollutants in water.At present,most of the existing detection methods are incapable of real-time monitoring on site,or possible to cause secondary pollution of water resources.The fluorescence method has the characteristics of accurate detection,on site detection etc.,which attracts a lot of attentions.In this thesis,gold nanoclusters were investigated.The gold nanoclusters were prepared using different protecting agents.The two antibiotics were detected.The gold nanoclusters can be further used in the detection of actual water samples.(1)Preparation,screening,characterization and optimization of gold nanoclusters based sensor The gold nanoclusters were synthesized using bovine serum albumin,glutathione and L-cysteine as protective agents.The mercury nanoclusters with glutathione as the protective agent were also prepared.It is found that gold nanoclusters with glutathione as a protective agent were sensitive to antibiotics.Subsequently,the gold nanoclusters were characterize using transmission electron microscope,fluorescence spectrometer,ultraviolet-visible spectrometer,zeta potential meter,dynamic light scattering instrument,etc.The average diameter of the gold nanoclusters was 2.3 nm,and the lattice spacing was 0.240 nm,the UV absorption peak position is 400 nm.With the fluorescence excitation wavelength of 365 nm,the emission peak position is 590 nm.Then,the reaction conditions for gold nanocluster to detect antibiotics were optimized.The optimal conditions for the detection of tetracycline were pH 5,reaction time of 5 minutes,reaction temperature of 25°C,and metal nanocluster concentration of 5×10-5 mol/L.The optimal conditions for the detection of gentamycin were pH 6,reaction time of 2 minutes,reaction temperature of 25°C,and gold nanocluster concentration of 2.5×10-5 mol/L.(2)Gold nanoclusters for the detection of antibiotics in water Under optimal reaction conditions,tetracycline and gentamicin were detected in water.The detection range of tetracycline was 50μg/L~10mg/L.The detection limit was 5.31μg/L.The linear range of gentamicin was 0.5g/L~2.5g/L,and the detection limit was 62.85mg/L.The selectivity and reproducibility are good.The gold nanoclusters were used for the determination of actual water samples.The recoveries of tetracycline and gentamicin were 100%~107% and 102%~103%,respectively.The relative standard deviation was 0.56%~0.99%,and 0.50%~0.94%,respectively.Finally,the gold nanoclusters were immobilized on a paper substrate.The detection range of tetracycline ranged from 1 mg/L to 50 mg/L,and the detection range of gentamicin ranged from 0.5 g/L to 2.5 g/L.The detection limits were 1 mg/L and 0.5 g/L,respectively.Those gold clusters have potential on portable antibiotics detection strips.