Absorption and Resonance Rayleigh ScatteringSpectra of 6-Benzylaminopurine-Cu(Ⅱ)-Triphenylmthane Dyes Systems and Their Analytical Applications

Abstract

In HAc-NaAc buffer medium with pH=5.37~5.58,6-benzylaminopurine(6-BA) reacted with Cu(Ⅱ) to form a chelate [6-BA·Cu]2+,which further reacted with triphenylmethane dyes to form 2∶1(Lissamine green system),3∶1(fast green system) and 2.5∶1(water-soluble aniline blue system) ternary ion-associations,respectively.It resulted in the change of the absorption spectra,the great enhancement of resonance Rayleigh scattering(RRS) spectra and frequency doubling scattering(FDS) intensities.The maximum RRS wavelengths were all located at 372 nm.And the increased amount of absorption,the enhancement degree of RRS(ΔIRRS),FDS(ΔIFDS) were all proportional to the concentration of 6-BA during a certain range.The detection limits of methods for Lissamine green system were 5.48 μg/L,119.70 μg/L and 64.20 μg/L,respectively.Therefore,a sensitive method for determination of trace 6-BA with RRS spectrum in 6-BA-Cu(Ⅱ)-LG system has been developed.The method could be applied to the determination of 6-BA in bean sprouts with satisfactory results.In this paper,we used Gaussview 3.07 and Gaussian 03W softwares at a B3LYP/6-31G(base group) level based on the density functional theory(DFT) to calculate the charge distribution of 6-BA.Furthermore,the reaction mechanism and the main reasons for the enhancement of RRS of the Lissamine green system were preliminarily discussed.