| Summary: | 碩士 === 國立臺灣海洋大學 === 生物科技研究所 === 102 === In this study, we have prepared amorphous iron hydroxide/oxide immobilized reduced graphene oxide nanocomposites (FeOXH-rGO) with peroxidase-mimic activity for detection of sulfide (S2) ions. FeOXH-rGO nanocomposites were prepared by react with UV-partial-reduced GO (size~300 nm) with Fe2+ in Tris-borate solution (5.0 mM, pH 7.0). The amorphous FeO(OH) and Fe(OH)2 were self-assembly on the GO to form the FeOXH-rGO nanocomposites. The as-prepared FeOXH-rGO nanocomposites exhibit peroxidase-mimicking catalytic activity in the H2O2-mediated oxidation of Amplex Red (AR) to fluorescent resorufin. Our AR/FeOXH-rGO probe allows detection of H2O2 down to 50 nM within 10 min under microwave irradiation (170 W). The catalytic activity of FeOXH-rGO is significantly suppressed in the presence of S2 because of the formation of FeS on the FeOXH-rGO nanocomposites’ surfaces. The H2O2/AR–FeOXH-rGO probe provides a limit of detection (LOD; S/N = 3) of 50 nM for S2 with high selectivity (>100-fold) with respect to other anions. Taking advantages of their high stability and selectivity, we employed our H2O2/AR–FeOXH-rGO probe for the detection of S2 in hot spring samples (75.1–619.5 μM) and the results show good correlation (r = 0.98) with inductively coupled plasma mass spectrometry (ICP-MS) method. This label-free, rapid, and simple sensing system shows great potential for the detection of S2 ions in real samples.
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