Ultrasensitive fluorescent nanosensor for arsenate assay and removal using oligonucleotide-functionalized CuInS2 quantum dot@magnetic Fe3O4 nanoparticles composite

Herein, a novel oligonucleotide functionalized CuInS2 quantum dots@magnetic Fe3O4 nanocompositebased fluorescence turn off-on nanosensor for arsenate detection was reported. Amino terminal oligonucleotides were firstly covalent linked to the carboxyl on the surface of CuInS2 quantum dots (QDs), forming oligonucleotide functionalized CuInS2 QDs (55DNA-CuInS2 QDs). Then, Fe3O4 nanopartides adsorbed onto ssDNA-CuInS2 QDs, leading the fluorescence to turn off. Arsenate could displace the adsorbed ssDNA-CuInS2 QDs, and as a result the fluorescence turned on. The detection limit was down to 0.13 nmol L-1. The present approach had been successfully employed to detect arsenate in three kinds of water samples with satisfactory results. (C) 2015 Elsevier B.V. All rights reserved.