A homogeneous capillary fluorescence imprinted nanozyme intelligent sensing platform for high sensitivity and visual detection of triclocarban

A homogeneous capillary fluorescence imprinted nanozyme intelligent sensor based on a dual-function metalorganic framework (NH2-MIL-101(Fe)) has been developed for highly sensitive and visual determination of triclocarban (TCC). The NH2-MIL-101(Fe) exhibited peroxidase-like properties to oxidize o-phenylenediamine to 2,3-diaminophenazine with yellow fluorescence (570 nm), which in turn suppresses the intrinsic fluorescence peak (445 nm) owing to the inner filter effect. The capillary fluorescence detection system was constructed by inhaling molecularly imprinted polymers solution with H2O2 and o-phenylenediamine into the capillary, which realized the homogeneous distribution of molecularly imprinted polymers in the capillary without the tedious operation of coating the inner wall of the capillary. TCC restored the fluorescence at 445 nm while quenching the fluorescence at 570 nm, resulting in a color shift from yellow to green to blue. The linear range of the fluorescence capillary imprinted sensor was determined to be 10 pM- 3.5 nM with the detection limit of 8.5 pM. The fluorescence color was converted to RGB value by using the smartphone to calculate TCC concentration with the detection limit of 9.8 pM, which provided a novel method for the determination of environmental pollutants with the microvolume consumption (18 mu L/time).