Abstract:A new colorimetric method for the detection of tiopronin, a drug used to treat liver disease, was developed based on the morphological changes of triangular silver nanoprisms (AgNPRs) to modulate their local surface plasmon resonance (LSPR) absorption. Due to the high surface energy of the sharp corners of AgNPRs, they are easily etched by a certain concentration of Cl-. As a result, the morphology of AgNPRs changes from triangular flakes to smaller circular flakes, and the corresponding LSPR absorption bands are significantly blueshifted. When thiopronin coexists with AgNPRs, due to the special interaction between the thiol group of thiopronin and Ag, thiopronin plays an important role in protecting AgNPRs from Cl-etching, thus controlling the LSPR absorption bands of AgNPRs from being shifted. Based on this principle, a new colorimetric method for the visual detection of thiopronin was developed with a detection range of 001~05 μmol·L-1, which has been applied to the detection of thiopronin in injections and entericcoated tablets, and the results showed that there was no significant difference from the labeled amount with the recoveries of 953%~1025%.