Figure 5: In situ inspection of pesticide residues on food/fruit. (a) Normal Raman spectra on fresh citrus fruits. Curve I, with clean pericarps. Curve II, contaminated by parathion. Curve III, Shiners spectrum of contaminated orange modified by Au/SiO2 nanoparticles. Curve IV, Raman spectrum of solid methyl parathion. Laser power on the sample was 0.5 mW, and the collected times were 30s. (b) Schematic of the Shiners experiment. Reprinted with permission from reference 81. Copyright 2010 Nature Publishing Group.