关键词: Fe₃O₄, 过氧化物酶, 核酸, 重金属, 生物传感器

Abstract: Excessive heavy metal residues is one of the major food safety issues. To quickly and accurately determine the amount of heavy metals, this paper reported a colorimetric sensor for the quantification of Cd²⁺ and Pb²⁺. The peroxidase activity of Fe₃O₄ was used as the signal output tool and aptamer as the target specific recognition element. First, the detection method was determined by the feasibility analysis and the condition optimization, and the sensor performance was evaluated by sensitivity and specificity experiments. Under the optimum conditions, the sensor has a high selectivity over other competitive ions with the detection limits as low as 0.108 μmol/L for Cd²⁺ and 0.117 μmol/L for Pb²⁺. The method has the advantages of low cost, fast and simple detection process, visible to the naked eye, and the quantitative analysis can be realized by hand-held photometer. The establishment of the sensor would make it possible to detect heavy metals in real time and quickly, and provide a strong guarantee for food safety detection in China.

Key words: Fe₃O₄, peroxidase, nucleic acid, heavy metal, biosensor