Study On The Determination Of Trace Amino Acids Using High SERS Activity Gold Nanoflowers As Substrate

Gold nanoflowers(AuNF)with better surface-enhanced Raman scattering(SERS)activity were rapid prepared by microwave irradiation,to further form AuNF/AgCl substrate with high SERS activity,and using the blue-violet complex Ruhemann’s purple(RP)produced by the reaction of amino acid with ninhydrin as probe,a new rapid,highly selective and non-invasive method was established for the determination of trace amino acids with SERS spectral.The new method was applied to detect the content of amino acids in fruit juice,and the results were satisfactory.The main contents of the paper as the following:1.The characteristics of SERS spectral and their application were briefly introduced.The Common SERS substrates and their preparation methods were reviewed,and the characteristics and preparation method of AuNF were introduced emphatically.The significance,method and application of amino acid determination were summarized.The research content,purpose and significance of this paper were briefly described.2.AuNFs with high SERS activity were prepared by Microwave assisted method.Under the condition of microwave-assisted and 40℃ water bath heating,the novel AuNF sol was prepared by reducing the chloroauric acid with the newly prepared triethanolamine with ethylene glycol as the dispersant and stabilizer,its properties were studied by transmission electron microscopy,absorption spectra,RRS spectra and SERS spectra.The results showed that AuNF particle size was between 50～100 nm with more tips and rough surface,its maximum absorption peak at 601 nm with good tip effect,700 W microwave heating suitable time was 20 s.Taking the AuNF as the substrate and VBB as the probe,the intensity of SERS peak at 1618 cm-1 enhanced as increasing the concentration of’ AuNF.The AuNF/AgCI aggregates formed by the strong hydrophobic interaction can greatly enhance the SERS signal.3.Determination of Trace Amino Acids using high SERS activity AuNF/AgCl as substrate.The optimal conditions for the determination of Trace amino acids using AuNF/AgCI as substrate with high SERS activity as follows:pH 6.2 PBS.reaction at 85℃of 10 min,10.035 umol/L AuNF,0.23 mmol/L AgNO3 and 45 μmol/L NaCl.The intensity of SERS peak at 655 cm-1 increased linearly as amino acids concentration in the linear range(LR)of 0.0665~46.55 pmol/L with a detection limit(DL)of 0.05 pmol/L.The method was highly selective and sensitive to method of UV-vis and RRS.4.Determination of amino acids in fruit juice using high SERS activity AuNF/AgCl as substrate.The amino acid content of mango juice and litchi juice was determined by SERS working curve of isoleucine and arginine using high SERS activity AuNF/AgCl as substrate,the results of the amino acid content were 9.08 mmol/1 and 17.52 mmol/1,the recoveries of standard addition were 98.39%and 105.1%,and the relative standard deviations were 6.72%and 5.58%respectively with satisfactory results.5.Summary and Prospect of the paper.In this paper,the main work were briefly summarized,and the application prospect and the improvement direction of the new SERS method for the detection of trace amino acids were prospected.