Synthesis And Analysis Application Of Fluorescent Palladium Nanoclusters

Metal nanoclusters(NCs)are a kind of fluorescent nanomaterials composed of several or dozens of metal atoms.Due to their good fluorescent properties,nanometer size and low toxicity,they are considered as new nanomaterials that replace organic fluorophores and quantum dots.At present,metal nanoclusters inclede gold,silver,copper,palladium,platinum and other nanoclusters according to their composition atoms.Among them,palladium nanoclusters(Pd NCs)are mainly applied in the field of catalysis,and there are few reports on the fluorescence properties of palladium nanoclusters.Therefore,obtaining high stability and fluorescence intensity are the key scientific problems that need to be solved in the development field of Pd NCs fluorescence nanosensors.Based on this,this paper successfully synthesized Pd NCs with high stability and high fluorescence intensity by chemical reduction method using polyvinylpyrrolidone,glutathione,and polyethyleneimine as stabilizers,respectively.Luminescent nanosensors have been successfully applied to the analysis of tetracycline(TC),2,4-dinitrophenol(2,4-DNP)and oxytetracycline(Ot).The specific research contents are summarized as follows:Chapter 1: The performance,preparation methods and development status of metal nanoclusters(NCs)were introduced,and the research content of this paper is briefly described.Chapter 2: Highly fluorescent Pd NCs were synthesized by chemical reduction using polyvinylpyrrolidone(PVP)as the stabilizer and ascorbic acid as a reducing agent.Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)were used to characterize the functional groups existing on the surface of the Pd NCs.The results showed that the surface of the Pd NCs contained-NH2,-OH,-COOH and other groups,making them have good water solubility.We used it as a photoluminescentnanosensor.The Pd NCs have high fluorescence intensity,good stability under p H conditions and high ion concentration,and good photobleaching resistance under continuous UV irradiation.The Pd NCs was used as a highly selective and sensitive fluorescent nanosensors for detection of TC.Based on this,we established a fluorescence analysis method for the detection of TC.Its detection range is 10-220 n M and the detection limit is 0.03 n M.The developed polyvinylpyrrolid one-stabilized palladium nanoclusters have been successfully used for the determination of TC in honey spiked samples with good recovery.Chapter 3: Chemical reduction method was used to synthesize glutathione(GSH)stabilized fluorescent Pd NCs.The synthesized Pd NCs were characterized by UV-vis Abs spectra,FL spectra,X-ray electron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR),and high-resolution transmission electron microscopy(HR-TEM),etc.The Pd NCs can stably exist at various p H and high ion concentration,and has excellent light resistance under ultraviolet light irradiation.As a new type of fluorescent nanosensor,the Pd NCs can realize high sensitivity and high selectivity the detection of 2,4-dinitrophenol(2,4-DNP),and the concentration range of 2,4-DNP is in the range of 10-230 n M.There is a good linear quenching relationship between the fluorescence quenching and Pd NCs and 2,4-DNP,and its correlation coefficient is 0.9961.This method was successfully applied to the detection of 2,4-DNP in tap water.Chapter 4: Polyethyleneimine(PEI)stabilized Pd NCs was synthesized by a chemical reduction method and used as a fluorescent nanosensor for the detection of oxytetracycline(Ot).The reaction time,reaction temperature and stability of the synthesis of the fluorescent Pd NCs were investigated.The spectral characteristics,surface structure and morphology of the Pd NCs were studied.The selectivity,sensitivity and reproducibility of the nanosensor were also investigated.The experimental results show that the Pd NCs havegood biocompatibility,stability,and photobleaching resistance in aqueous solution.As a nano-sensor,it has high sensitivity,high selectivity and reproducibility.The fluorescence quenching effect showed a good linear relationship with the degree of fluorescence quenching of Pd NCs and Ot in the range of 10-440 n M,with a correlation coefficient of 0.99.Based on this,we have established a new nanosensing analysis method for detecting Ot.Chapter 5: The application of palladium nanoclusters as fluorescent nanosensors was summarized and gived outlook about this work.