Figure 1. Optical characterization of TPEARG. (A) Structure and identification mechanism of TPEARG. The fluorescence intensity of TPEARG enhanced with the increasing of the solution (B) polarity and (C) viscosity. (D) When interacted with arginase, the TPEARG emitted fluorescence and the intensity increased with the concentrations of arginase. (E) Linearship between the fluorescence intensity of TPEARG and concentrations of arginase. (F, G) Selectivity of TPEARG to several interferential factors. 1 μM TPEARG was introduced in these experiments. λex= 390 nm. The data are expressed as mean ± SD.