Electrochemical sensor based on in situ polymerized ion-imprinted membranes at graphene modified electrode for palladium determination

Abstract

In this work, an amperometric sensor was developed for the selective recognition and sensitive determination of palladium in complex matrices using a glassy carbon electrode (GCE) modified with a novel ion-imprinted membrane (IIM) and graphene. Graphene enhanced the sensor's electron transfer and sensitivity. The electrode surface was first directly modified with graphene through the electrodeposition of graphene oxide. An ion-imprinted polymer membrane was subsequently synthesized on this modified surface via in situ polymerization in acetonitrile using allylurea (NAU) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linking agent, and azobisisobutyronitrile as an initiator at a molar ratio of template (PdCl2) to NAU to EGDMA of 1:4:40. Amperometric i-t curves were measured for the determination of palladium. The designed modified electrode was shown a linear response to Pd(II) ions in the range of 2.0×10−8–2.0×10−4molL−1 of Pd(II) ion with a detection limit of 6.4×10−9molL−1. Metal ions present at concentrations 15 times higher than that of Pd(II) did not interfere with the determination of Pd(II). The sensor was successfully applied to determine palladium in catalyst and plant samples with a relative standard deviation (RSD) of less than 3.3% (n=5) and recoveries in the range of 99.2–106.5%.