Au-Ag Core-Shell Nanospheres for Surface-Enhanced Raman Scattering Detection of Sudan I and Sudan II in Chili Powder

Figure 5

IR and Raman spectra for Sudan I and Sudan II; representative SERS spectra of 1 mg/L Sudan II solution adsorbed on Au@Ag substrates synthesized with 1 mmol/L AgNO₃ solution and various amounts of Au seeds including (a) 0.45 mL, (b) 0.9 mL, (c) 1.5 mL, and (d) 4.5 mL, as well as with 0.9 mL Au seeds and different concentrations of AgNO₃ solutions including (e) 0.5 and (f) 2 mmol/L.