A simple and sensitive electrochemical aptasensor for determination of Chloramphenicol in honey based on target-induced strand release

A novel electrochemical aptasensor for highly sensitive detection of Chloramphenicol (CAP) in honey was successfully developed based on target-induced strand release (TISR). CAP aptamer was immobilized on electrode and then hybridized with the complementary biotinylated detection probe to form aptamer/DNA duplex. In the presence of CAP, the TISR resulted in the dissociation of biotinylated detection probe from the electrode. Then the binding of streptavidin–alkaline phosphatase (ST–AP) to the remaining biotinylated detection probe led to enzyme-amplified electrochemical signal, which decreased with the increase of CAP concentration. Under optimal conditions, the electrochemical signal was linear with the logarithm of CAP concentrations in the range from 1 nM to 1000 nM with the detection limit of 0.29 nM of CAP. In addition, the designed strategy allowed the direct analysis of real honey samples and the results showed a good agreement with conventional LC–MS/MS method.