Figure 1.

UV–Vis absorption spectra of different colloidal solutions.

Notes: (A) UV–Vis absorption spectra of AuNP solutions synthesized using 0.25 mL (a), 0.5 mL (b), 1 mL (c), 1.5 mL (d) and 2 mL (e) OH extracts. (B) UV–Vis absorption spectra of AuNP solutions synthesized using 0.5 mL (a), 1 mL (b) and 1.5 mL (c) OF extracts. The insets present two optical images of the colloidal solutions synthesized using the two types of extracts. The colloids were diluted 1:1 with double distilled water prior to the measurements.

Abbreviations: UV, ultraviolet; Vis, visible; AuNP, gold nanoparticle; OH, Origanum herba; OF, Origanum folium.