Determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin based on SERS substrates composited of Au nanoparticles supported on twice-oxidized graphene oxide.

A surface-enhanced Raman spectroscopy (SERS) substrate consisting of Au nanoparticles supported on twice-oxidized graphene oxide (ro-GO) for the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was prepared. The Raman shift at △v = 779, 993, and 1203 cm was collected on the excitation condition of λ = 785 nm for the qualitative identification of 2,3,7,8-TCDD in milk. The peak at △v = 1203 cm was selected as the characteristic peak for quantitation. The quantitation calculation was realized in the concentration range 10 to 100 ng mL with a limit of detection of 3.24 ng mL in milk samples. The average recoveries of 2,3,7,8-TCDD in milk were 60.6-68.6% with relative standard deviations less than 6.4%. The long-term stability of the substrates was approximately 180 days at 4 °C. Further, the SERS method for the determination of 2,3,7,8-TCDD in milk samples based on the optimized hybrid SERS substrate and corresponding pre-treatment procedure is proposed. Graphical abstract Schematic representation of surface-enhanced Raman spectroscopy (SERS) determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in milk samples by Au nanoparticles supported on twice-oxidized graphene oxide (ro-GO/AuNP) as a substrate.