"Light-on"Colorimetric Assay for Ascorbic Acid Detection via Boosting the Peroxidase-like Activity of Fe-MIL-88

A label-free"light-on"colorimetric assay for ascorbic acid(AA)determination is unprecedentedly devised by regulating the intrinsic peroxidase-mimetic activity of the Fe-MIL-88.AA can reduce Fe(Ⅲ)presented in Fe-MIL-88 to Fe(Ⅱ),which will dramatically promote the hydroxyl radicals(·OH)conversion efficiency of H_(2)O_(2)through a Fenton reaction,and effectually accelerate the Fe-MIL-88 catalyzed chromogenic reaction of 3,3′,5,5′-tetramethylbenzidine(TMB)-H_(2)O_(2).Redox reaction between AA and H_(2)O_(2)also can produce·OH and promote this chromogenic reaction.Thus,quantification of AA is real-ized via determining the enhanced colorimetric signals.The linear range is 0.5−40μM with a detection limit of 0.12μM.Furthermore,the straightforward yet effective colorimetric strategy with the merits of simplicity,cost-effectiveness,high accuracy,specificity,and sensitivity is widely utilized to determine the concentrations of AA in serological tests.