High-quality carbon dots: synthesis, peroxidase-like activity and their application in the detection of H sub(2)O sub(2), Ag super(+) and Fe super(3+)

In this paper, bright and high-quality carbon dots (CDs) were prepared by refluxing a membranous carbonized beta -cyclodextrin in nitric acid. The structure and optical properties of the CDs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), fluorescence spectrophotometry (FL), X-ray diffraction (XRD) and Raman spectroscopy. The mechanism for the formation of the CDs is also discussed. As-prepared CDs could be used as peroxidase mimics for the detection of H sub(2)O sub(2). The results indicate that the CDs are capable of rapid and sensitive detection of H sub(2)O sub(2) in the linear range from 2 10 super(-6) to 5 10 super(-4) mol L super(-1) and the limit of detection of H sub(2)O sub(2) is as low as 1 10 super(-6) mol L super(-1). More importantly, the peroxidase-like activity of the CDs is expanded to the detection of some oxidative ions (such as Fe super(3+) and Ag super(+)). The linear ranges for Fe super(3+) and Ag super(+) were 8 10 super(-6) to 1 10 super(-4) mol L super(-1) and 5 10 super(-6) to 1 10 super(-4) mol L super(-1) respectively, with corresponding detection limits of 8 10 super(-7) mol L super(-1) and 5 10 super(-7) mol L super(-1) respectively.