β−cyclodextrins-based inclusion complexes of CoFe 2O 4 magnetic nanoparticles as catalyst for the luminol chemiluminescence system and their applications in hydrogen peroxide detection

Abstract

β−cyclodextrins ( β−CD)-based inclusion complexes of CoFe 2O 4 magnetic nanoparticles (MNPs) were prepared and used as catalysts for chemiluminescence (CL) system using the luminol–hydrogen peroxide CL reaction as a model. The as-prepared inclusion complexes were characterized by XRD (X-ray diffraction), TGA (thermal gravimetric analysis) and FT-IR. The oxidation reaction between luminol and hydrogen peroxide in basic media initiated CL. The effect of β−CD-based inclusion complexes of CoFe 2O 4 magnetic nanoparticles and naked CoFe 2O 4 magnetic nanoparticles on the luminol–hydrogen peroxide CL system was investigated. It was found that inclusion complexes between β−CD and CoFe 2O 4 magnetic nanoparticles could greatly enhance the CL of the luminol–hydrogen peroxide system. Investigation on the kinetic curves and the chemiluminescence spectra of the luminol–hydrogen peroxide system demonstrates that addition of CoFe 2O 4 MNPs or inclusion complexes between β−CD and CoFe 2O 4 MNPs does not produce a new luminophor of the chemiluminescent reaction. The luminophor for the CL system was still the excited-state 3-aminophthalate anions (3-APA*). The enhanced CL signals were thus ascribed to the possible catalysis from CoFe 2O 4 MNPs or inclusion complexes between β−CD and CoFe 2O 4 nanoparticles. The feasibility of employing the proposed system for hydrogen peroxide sensing was also investigated. Experimental results showed that the CL emission intensity was linear with hydrogen peroxide concentration in the range of 1.0 × 10 −7 to 4.0 × 10 −6 mol L −1 with a detection limit of 2.0 × 10 −8 mol L −1 under optimized conditions. The proposed method has been used to determine hydrogen peroxide in water samples successfully.