Colorimetric/photothermal dual-mode sensing detection of ascorbic acid based on a Ag[i] ion/3,3',5,5'-tetramethylbenzidine (TMB) system.

In this work, a novel strategy of colorimetric and photothermal dual-mode sensing determination of ascorbic acid (AA) based on a Ag/3,3',5,5'-tetramethylbenzidine (TMB) system was developed. In this sensing system, Ag could oxidize TMB with a distinct color change from colorless to blue color, strong absorbance at 652 nm and a photothermal effect under 808 nm laser irradiation due to the formation of oxidized TMB (oxTMB). When AA was present, oxTMB was reduced accompanied by a change from blue to colorless, and a decrease in absorption peak intensity and the photothermal effect.