Fast detection of triazine herbicides on a microfluidic chip using capillary electrophoresis pulse amperometric detection

We report simple and rapid capillary electrophoresis (CE) separation followed by in-channel pulsed amperometric detection (PAD) of three common triazine herbicides: simazine, atrazine and ametryn that are used to control broad leaf weeds and annual grasses. For their detection in soil and groundwater samples, a CE–PAD microfluidic chip was fabricated using standard photolithography methods. Cyclic voltammetry was conducted on these herbicides that exhibited a characteristic cathodic peak at −0.70 V for simazine or atrazine and −0.80 V for ametryn, without any anodic peak at reverse scan, indicating that the cathodic peaks were irreversible electron transfer processes. For effective CE–PAD separation of triazine complex, the capillary was filled with 1.5% agarose. The pulsed amperometric detection of these chemicals ensured better sensor response and low electrode fouling. The average electropherogram of simazine, atrazine and ametryn showed single peaks at 58, 66 and 74 s, respectively at 20 V/cm separation potential. A mixture of all three herbicides showed similar separated peaks. HPLC was also conducted in a soil spiked with these pollutants to compare the method. The results hold the promise of detecting triazines within a very short time.

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► Atrazine, simazine and ametryn were separated and detected by CE-PAD.
► A microfluidic chip was fabricated for this method.
► Soil spiked with these triazines was satisfactorily validated using HPLC.
► Its application demonstrates potential for pesticide detection at shorter migration time.