ABSTRACT
In this paper, Fe3O4/MnO2doped graphene molecularly imprinted hybrid material ( Fe3O4/MnO2-MIP@ RGO ) was successfully synthesized via reversible addition fragmentation chain transfer ( RAFT ) molecularly imprinting technique by using methacrylic acid as functional monomer, divinylbenzene as cross-linker, Fe3O4/MnO2@ RGO as carrier, and 17β-estradiol ( 17β-E2 ) as template molecule. A novel molecularly imprinting electrochemical sensor by using Fe3O4/MnO2-MIP@ RGO modified electrode was constructed to specifically detect trace 17β-E2 in water. The experimental results showed that the Fe3O4/MnO2-MIP@ RGO electrochemical sensor exhibited rapid and linear current response to 17β-E2 in water samples with a linear range of 4 nmol/L to 0. 8 μmol/L ( R=0. 9852) , the detection limit was 47. 2 pmol/L (3σ) and the relative standard deviation (RSD) was from 2. 1% to 2. 5% . This study provides a simple and efficient, economical and reliable method for the monitoring of 17β-estradiol in the complex water environment.
ABSTRACT
A colorimetric method was developed for detection of mercury based on the inhibition of oxidation of peroxidase substrates. The as-prepared gold nanoclusters ( Au NCs), which has been stabilized and reduced by Glutathione (GSH), can effectively catalyze the H2 O2-TMB to generate a blue color signal. It is interestingly that Hg2+ can inhibit the oxidation of peroxidase substrates, thus causing a color diminished. Taking advantage of the inhibitive effect of Hg2+, a novel Hg2+ sensor has been developed. In this system, sensing conditions, including pH of the buffer solution, substrate concentration and time, were optimized. Under the optimal conditions, the probe showed a linear range of 10 - 300 nmol/ L ( R2 = 0. 997) with a detection limit of 6. 26 nmol/ L. In addition, this sensor exhibited good selectivity and sensitivity for Hg2+against other common environmental mental ions, providing a new method for water analysis.