Fe3O4 Magnetic Nanoparticles as Peroxidase Mimetics Used in Colorimetric Determination of 2,4-Dinitrotoluene

Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) were prepared by co-precipitation method, which possessed intrinsic peroxidase-like activity. It was found that the as-prepared Fe3O4 MNPs could not only catalyze the oxidation of peroxidase substrate, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate acid) (ABTS) by H2O2 to produce the colored product with maximum absorbance at 417 nm, but also catalyze the oxidation of 2,4-dinitrotoluene (DNT) by H2O2 and thus consume H2O2 in the reaction system. On the basis of the reaction mechanism described above, a novel colorimetric reaction system of Fe3O4 MNPs-ABTS-H2O2-DNT was established for the determination of trace amount of DNT. Some key influencing factors of the proposed Fe3O4 MNPs-ABTS-H2O2-DNT system were systematically discussed and optimized. Under the optimal conditions, the absorbance of the system at 417 nm displayed a good linear relationship with DNT concentration in the range from 5.0 × 10−7 M to 2.0 × 10−5 M with a detection limit of 1.5 × 10−7 M (S/N = 3). These results demonstrated that the constructed colorimetric method was simple, rapid and sensitive enough for the detection of DNT, which would have a great potential in the application of on-line monitoring of DNT in environmental water samples

Fe3O4 MNPs could not only catalyze the oxidation of ABTS by H2O2 to produce colored product, but also catalyze the oxidation of DNT and thus consume H2O2 in the reaction system. Based on this mechanism, a novel colorimetric reaction system of Fe3O4 MNPs-ABTS-H2O2-DNT was established for the determination of DNT.Figure optionsDownload as PowerPoint slide