AbstractA molecularly imprinted polymer microsensor was synthesized onto the surface of a carbon fiber microelectrode (CFME) by cyclic voltammetry between −0.1 V and +1.35 V at a scan rate of 50 mV s−1. The monomers aniline and o‐phenylenediamine (o‐PD) were electrocopolymerized in the presence of the template (metamitron) in an aqueous medium of 0.1 M H2SO4. In order to obtain a sensor with the highest number of imprinted sites as possible, different experiments related to the polymerization process were carried out. The response of the synthesized microsensor was linear to the metamitron in the range between 10−6 and 10−4 with sensitivity of 0.143 nA μM−1 with good repeatability (<9% RSD). Employing these experimental conditions, the microsensor was able to distinguish the metamitron from other closely related triazines like metribuzin or isomethiozin.