Improvement of peroxidase-like activity and application for detection of H 2 O 2 and dopamine for SDBS-Cu-CuFe 2 O 4

Cu-CuFe 2 O 4 exhibited excellent activity as a peroxidase, which the affinity to H 2 O 2 was significantly enhanced. However, the affinity to 3, 3’, 5, 5’- tetramethylbenzidine (TMB, another substrate) was weaker than Horseradish enzyme (HRP, a natural enzyme). At the present, Cu-CuFe 2 O 4 was modified by an anionic surfactant (sodium dodecyl benzene sulfonate, SDBS) through a one-step method, which was named as SDBS-Cu-CuFe 2 O 4. More negative zeta potential was found for SDBS-Cu-CuFe 2 O 4, and the affinity to positive charged TMB was enhanced. The peroxidase-like activity and the peroxidase-like activity of per unit concentration were also improved. The catalytic efficiency was increased for TMB as the substrate. Effects on peroxidase-like activity of SDBS-Cu-CuFe 2 O 4, such as zeta potential, redox ability, electron transfer and order of the addition of TMB and H 2 O 2 in the system, were studied in detail. The peroxidase-like mechanism was proposed. SDBS-Cu-CuFe 2 O 4 was used to rapidly detect H 2 O 2 and dopamine (DA) with the smallest limit than reported.