Studies On The Detection Of Antioxidants Of BHA And BHT By Surface-Enhanced Raman Scatteirng

Butylated hydroxyanisole （BHA） and2,6-Di-t-butyl-p-hydroxytoluene （BHT） are commonantioxidants used in foods and food packaging materials as necessary additive to protect theprimary properties and nutrients of the materials. However, they have been questioned due to itspotential risk. Therefore, the presence of this synthetic antioxidant in foods should be carefullymonitored. Surface-enhanced Raman spectroscopy （SERS） could provide a more rapid andcost-effective method. Nowadays, SERS is being extensively applied in various food-relatedareas, such as food additives. The objective of this study was to investigate the feasibility ofusing SERS method for rapid detection of BHA and BHT.First, after optimized the structure and calculated the theory Raman spectra of BHA andBHT using Density Functional Theory （DFT） and software Gaussian03, we got the peak resultswith high match quality between theoretical and experimental Raman spectra. We identified thevibration assignments of all peaks, analyzed the enhanced mechanism and adsorbed behavior ofBHA and BHT on the surface of Au nanoparticles. Then we demonstrate that the enhancedmechanism of BHA and BHT both contain electromagnetic enhancement mechanism andcharge-transfer mechanism, BHA and BHT adsorbed on the surface of Au nanoparticles byAu-O.Second, we confirmed the experimental condition of the detection of BHA and BHT usingSERS.1) After compared the enhanced effects of Au colloidal nanoparticles, Silver colloidalnanoparticles, Au-filter membrane complex substrates and Au-collumn complex substrates, wefound the Au colloidal nanoparticles could create best enhanced result;2) compared withdifferent Au size, we choose the Au colloidal nanoparticles of50nm as the SERS substrate inthis study;3) compared with four solvent’s SERS effects and choose methanol as the solvent ofBHA and BHT;4) compared with different detect carrier, different mixed ratio and adsorptiontime of Au and determinand, confirmed the best choices are tin foil, Au:determinand=10:2,adsorption time=14min.Finally, we confirmed the qualified peaks of BHA are420and480cm^-1, BHT are464,556and766cm^-1. Established SERS detection method and the standard curve using on realisticsample detection, choose480cm-1and766cm-1as the quantitative peaks of BHA and BHTrespectively, the limit of detection of them are both10μg/mL, linear equation are BHA:y=4.3254x+374.41, R²=0.9803; BHT: y=236.06x-220.3, R²=0.9761. In addition, compared withthe SERS and HPLC result of realistic sample and got the consistent between them, the relatedcoefficient （r） were0.9993and0.9997respectively. It demonstrates that SERS has a potentialapplication for rapid qualified and preliminary quantitative detection of BHA and BHT in foodsand food packaging materials.