We also noticed that the previous report had done similar researches on silver TNPs, however, the sensitivity for iodide detection was only at 1 M [36]. The distinct difference in sensitivity could be ascribed to the different silver TNPs preparation methods by which produced silver TNPs with different thickness. A recentreport by Xia and co-workers [61] indicated that the thickness of silver TNPs depends on the capping agents used in the preparation. When citrate was added as capping agent, lateral growth was more favorable and thus the formation of thin silver plates withlarge lateral dimensions. In contrast, thicker silver nanoplates were obtained because of vertical growth if citrate was substituted bypoly (vinylpyrrolidone) (PVP) [61]. In this paper, preparation of silver TNPs was different from others, in which PVP was excluded and only citrate was added as capping agent [50]. Compared with other silver TNPs with thicker plate and polymer caps, thin silver TNPs are favourble to interact with low concentration of iodide.