Enzyme mimetics have been widely applied on H2O2 assay, but it is still challenging and interesting to realize the sensitive detection for ultra-trace H2O2. Here, an ultrasensitive Raman assay method based on novel WO3@IP6-Fe3+ enzyme mimetics with peroxidase-like activity was established. WO3 microspheres (MSs) were found to have weak peroxidase-like activity, and the combination of IP6-Fe3+ and WO3 can produce stronger activity. WO3@IP6-Fe3+ MSs showed polyhedron-like structure, uniform size, and smooth surface. Although WO3@IP6-Fe3+ enzyme mimetics have low catalytic efficiency and high absorbance background, the proposed Raman method can bypass the above problems. In Raman method, high concentration of WO3@IP6-Fe3+ can be used to overcome low catalytic efficiency without high absorbance background. Moreover, 3,3',5,5'-tetramethylbenzidine oxide has prominent characteristic Raman peak at 1608 cm-1, greatly improving the sensitivity and eliminating interference of impurities. Due to the high sensitivity and low background, Raman assay showed the ultra-low limit of detection (5.49 × 10-15 M), which was 4-7 orders of magnitude lower than other detection methods. The ultrasensitive Raman assay not only provided the possibility for the enzyme mimetics-based detection of ultra-trace H2O2, but also enable the enzyme mimetics with low activity to be applied.
Keywords: Enzyme mimetics; H(2)O(2); Raman; WO(3)@IP6-Fe(3+) MSs.
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