A certain concentration of silver TNPs was mixed with 100 LBritton–Robinson (B–R) buffer solution (20 mM, pH, 6.8) and a cer-tain concentration of KI in 1.5 mL clear centrifugal tube and then diluted to 1.0 mL. The mixture in the clear centrifugal tube was vortexed vigorously at once after each addition of the interacting additives. After standing for 30 min, the mixtures were directly used for spectrometric detection or picture capturing.