A Non-Enzymatic Electrochemical Sensor for Glyphosate Adopting Surface Modified Screen-Printed Electrodes

In this study, a lab-on-chip electrochemical sensor was developed for ultratrace determination of glyphosate. A single-step approach was adopted for the surface modification of screen-printed electrodes using reduced graphene oxide. Cyclic voltammetry and electrochemical impedance spectroscopy were employed to characterize the electrochemical behavior of the modified electrode. The modified electrode exhibited lowered electron transfer resistance, improved current response, and demonstrated selectivity and sensitivity toward glyphosate. Differential pulse voltammetry was employed to quantify glyphosate. The detection limit for glyphosate was achieved up to 0.144 nmol L-1 for a wide concentration range of 1 to 1000 nM. The proposed sensor presents the advantage of nonenzymatically and specifically determining glyphosate and offers exceptional stability with a relative standard deviation of 3.3% for 10 days. Finally, the applicability of the developed technique was assessed by quantification of glyphosate in tap water and garden soil samples. The ease of fabrication and implementation of the proposed sensor can contribute to the quest for on-site determination of the ecological contaminants.