Adsorption of 2,6-di-t-butyl-p-hydroxytoluene (BHT) on gold nanoparticles: Assignment and interpretation of surface-enhanced Raman scattering

2,6-Di-t-butyl-p-hydroxytoluene (BHT), a common antioxidant, has been implicated in oil foods and food packaging materials as a substance that could migrate into the food supply chain and cause suppression of human respiratory enzymes. In this study, BHT solutions in different solvents were measured by surface enhanced Raman spectroscopy (SERS) in combination with SERS-active substrates: gold colloidal nanoparticles. The limit of detection of BHT can reach the level of 10 μg/mL with SERS in methanol. The Raman peak at 766 cm−1 was used as the index of quantitative analysis and the correlation coefficient was 0.9761. These results demonstrated the applicability of utilizing SERS to detect low concentrations of BHT. By comparing the features of SERS peaks with the density functional theory (DFT)-calculated Raman spectrum, the adsorption behavior of BHT on the surface of gold nanoparticles was analyzed in detail and it was determined that the dominant contribution to the SERS signal in this case should be the electromagnetic enhancement mechanism. A charge-transfer mechanism also contributed to the SERS signal for BHT adsorbed on gold nanoparticles by the Phsingle bondO(H) (Ph = phenyl) coalescent format.