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 Pb2+ detection was proposed by using 8-17 DNAzyme as the recognition element and the reaction of H2O2 catalyzed by Fe-MIL-101 as the signal probe. Due to the high selectivity of the 8-17 DNAzyme to Pb2+, 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) to 10(-7 )mol.L-1, a lower detection limit of 1.74 x 10(-14) mol.L-1 and high selectivity to Pb2+. Tap water and river water were analyzed by the developed sensor with satisfying recoveries and RSD, demonstrating a promising practicability for the determination of Pb2+ 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.