Towards electrochemical surface plasmon resonance sensor based on the molecularly imprinted polypyrrole for glyphosate sensing

In this research the molecular imprinting technology was applied for the formation of glyphosate-sensitive layer. The glyphosate imprinted conducting polymer polypyrrole (MIPpy) was deposited on a gold chip/electrode and used as an electrochemical surface plasmon resonance (ESPR) sensor. The results described in this study disclose some restrictions and challenges, which arise during the development of glyphosate ESPR sensor based on the molecularly imprinted polymer development stage. It was demonstrated, that glyphosate could significantly affect the electrochemical deposition process of molecularly imprinted polymer on the electrode. The results of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and surface plasmon resonance (SPR) have demonstrated that glyphosate molecules tend to interact with bare gold electrode and thus hinder the polypyrrole deposition. As a possible solution, the formation of a self-assembled monolayer (SAM) of 11-(1H-Pyrrol-1-yl)undecane-1-thiol (PUT) before electrochemical deposition of MIPpy and NIPpy was applied. Dissociation constant (K-D) and free energy of Gibbs (Delta G(0)) values of glyphosate on MIPpy and Ppy without glyphosate imprints (NIPpy) were calculated. For the interaction of glyphosate with MIPpy the K-D was determined as 38.18 +/- 2.33.10(-5) and Delta G(0) as -19.51 +/- 0.15 kJ/mol.

Automated summary

This research utilized molecular imprinting technology to create a glyphosate-sensitive layer for an electrochemical surface plasmon resonance (ESPR) sensor. The study revealed the restrictions and challenges encountered during the development of glyphosate ESPR sensor using molecularly imprinted polymer. It was found that glyphosate interfered with the deposition process of the polymer, but the problem was partially overcome by using a self-assembled monolayer before deposition. The dissociation constant and free energy of Gibbs values for the glyphosate-MIPpy interaction were calculated.