A novel electrochemical Pb2+sensor with low background response has been constructed based on the specific affinity between the electroactive Alcian blue(AB)and G-quadruplex-Pb2+(G4-Pb2+).First,the G4 sequence with terminal thiol modification was assembled onto the gold electrode surface through Au-S bonding.When the target analyte(Pb2+)does not exist,AB does not interact with the G4 molecule,and no Faraday signal is observed on the electrode surface.Nevertheless,in the presence of Pb2+,it specifically induces the conformational change of the G4 from free coil situa-tion to a rigid G4-Pb2+structure,which can adsorb AB onto the electrode surface through π-π conju-gation,thereby generating a measurable Faraday signal.Based on this,the sensor can realize the low background electrochemical detection of Pb2+.The quantitative analysis results under optimal experi-mental conditions indicate that the sensor,using AB as a signal probe,can detect Pb2+within a con-centration range of 4.9 to 39 μmol/L.The detection limit,based on a signal-to-noise ratio of 3,is 0.13 μmol/L.The method has good specificity and can be used for the detection of Pb2+in tap and riv-er water samples.
关键词
电化学传感器/G-四联体/铅离子/核酸适体/阿尔新蓝
Key words
electrochemical sensor/G-quadruplex/Pb2+/aptamer/Alcian blue
万方数据