Highly efficient electrochemical detection of lead ion using metal-organic framework and graphene as platform based on DNAzyme

Based on the electrode modified by the carboxyl-functionalized graphene, a highly sensitive electrochemical sensor for Pb 2+ detection was proposed by using 8–17 DNAzyme as the recognition element and the reaction of H 2 O 2 catalyzed by Fe-MIL-101 as the signal probe. Due to the high selectivity of the 8–17 DNAzyme to Pb 2+ , the excellent catalytic ability of Fe-MIL-101 and the advantages of graphene, the proposed electrochemical sensor exhibited an excellent sensing performance with a wide linear range of 10 −13 to10 −7 mol·L −1 , a lower detection limit of 1.74 × 10 −14 mol·L −1 and high selectivity to Pb 2+ . Tap water and river water were analyzed by the developed sensor with satisfying recoveries and RSD, demonstrating a promising practicability for the determination of Pb 2+ in the real sample analysis. Furthermore, the proposed strategy could be extended to the determination of other metal ions just by changing the specific DNAzymes.