A Cu2(OH)3Cl-CeO2 nanocomposite with peroxidase-like activity, and its application to the determination of hydrogen peroxide, glucose and cholesterol

A nanomaterial of the chemical composition Cu-2(OH)(3)Cl-CeO2 and with a large surface area is shown to be a viable peroxidase mimetic. It was synthesized by co-precipitation of an aqueous solution containing Ce(III) chloride, Cu(II) chloride and hexamethylenetetramine by adding an ionic liquid. The material was characterized by scanning electron microscopy and X-ray powder diffractometry. The composite possesses peroxidase-like activity and catalyzes the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine by H2O2 to produce a blue product. Based on this finding, a simple, rapid and selective colorimetric method was worked out for the determination of glucose and cholesterol by using the respective oxidases and by quantifying the H2O2 formed. Both glucose and cholesterol can be determined by this method at levels as low as 50 A mu M.