Silver nanoparticles/polymethacrylic acid (AgNPs/PMA) hybrid nanocomposites-modified electrodes for the electrochemical detection of nitrate ions

• Synthesis of Ag nanoparticles (AgNPs) embedded in polymethacrylic acid (PMA) nanocomposites.
• Modification of SPCE electrodes by AgNPs/PMA nanocomposites.
• Voltammetric and amperometric sensor based on modified electrodes for detection of nitrate ions.

AgNPs/PMA hybrid nanocomposite materials with different Ag loadings have been synthesized using a simple chemical route assisted by UV irradiation. The hybrid composites were characterized by means of SEM and TEM, UV–vis spectroscopy and XPS. The as synthesized hybrid samples, composed of small Ag nanoparticles (AgNPs) embedded within the PMA (poly-methacrylic-acid) matrix, have been used to modify the working electrode of disposable screen printed carbon electrodes (SPCEs). It has been observed that hybrid composite with the lowest Ag loading forms dendritic silver structures on the surface of working electrode, whereas at higher loadings massive structures were formed. The electrocatalytic properties of the AgNPs/PMA/SPCEs were investigated toward the reduction of nitrate at neutral pH. Based on these modified electrodes, both voltammetric and amperometric sensors were developed for the electrochemical sensing of nitrate. Voltammetric sensor showed a wide linear range (0–20 mM) and high sensitivity (130 μA mM−1 cm−2).

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