The invention discloses an electrochemical sensor, a preparation method thereof, a detection
system and application. The preparation method of the electrochemical sensor comprises the following steps: step 1, modifying a
glassy carbon electrode with carbon nano onion; step 2, putting the
glassy carbon electrode modified in the step 1 into a prepolymerization solution containing
metoprolol for cyclic electropolymerization treatment; 3, the
glassy carbon electrode treated in the step 2 is placed in a
hydrochloric acid solution to be subjected to
elution treatment, and the electrochemical sensor is obtained after
elution is completed. Aiming at the technical
bottleneck of
rapid detection of
metoprolol, the invention provides the electrochemical sensor, the electrochemical sensor shows excellent selectivity,
repeatability and stability on
metoprolol, the measurement has a wide
linear range, the limit of detection (LOD) value is extremely low, and the electrochemical sensor can be used for detecting the concentration of metoprolol in metoprolol tablets or
urine.