Detection Of Bpa By Surface-enhanced Raman Scattering

Bisphenol A(BPA) is an important crude material in chemical industry. It is an essential intermediate for producing polycarbonate, epoxy resin, polysulfone, modified phenolic resin, and other polymers. However, BPA has been identified as a type of Endocrine Disrupting Chemicals (ECD) that can penetrate and cause damages to human bodies during handling. As a result, the safety of BPA becomes a public concern and draws increasing attentions. This paper studied the Surface-Enhanced Raman Spectroscopy(SERS) of BPA and developed a new detecting method for this compound. The following part is the summary of this study.1,In order to show the structure and raman spectroscopy of BPA, density functional theory calculations were performed with Gaussian 03 at the RB3LYP level and with the 6-311G(d) basis set, which also attribute to detail the assignment of all vibrations.2,The gold nanoparticles were prepared as the substrate of Surface Enhanced-Raman Spectroscopy through citrate reduction method. Transmission Electron Microscopy (TEM) is employed to investigate the morphologies of the substrate. The optical properties of the nanoparticles were examined by the UV-vis spectra. In order to maximize the signal from BPA, selection of available solvent and acid or base, orthogonal trial design, and optimization of the ratio of reagents have been employed in our study. Enhanced, Normal, and Theoretical Raman were compared to investigate the mechanism of BPA enhancement: the nanoparticles will aggregate and the gap between those molecules will shrink in acidic conditions, which can improve the surface-enhanced Raman scattering signal of BPA through the physical electromagnetic; at the same time, The Hydrogen atom break away from Oxygen atoms ,BPA was absorbed to gold nanoparticle with =CO- and benzene ring stands perpendicularly upright against the surface of golden gel, which will lead to the enhancement of the benzene ring skeleton vibration.3,The method for detecting the BPA in packaging material (PC) has a good linear relationship between 0.5mg/L and 50mg/mL. The content of BPA in baby's bottle made of PC was detected and chosen for the recovery test with three levels BPA additives: 4ug/g, 8ug/g, and 15ug/g. The recoveries of three level tests were 88.00%~ 101.40% and their relative standard deviations were between 1.18%~3.92%. The results from our study were very close to the one of HPLC-UV detecting method, so the detecting method we developed has proved to be validated and reliable and can be used for many applications.