Highly sensitive nanoplatform based on green gold sononanoparticles for phenol determination in olive oil

Abstract

Here, we describe a novel, fast, simple and green method for synthesis of gold sononanoparticles (AuSNPs) employing three different parts of Geranium (Pelargonium graveolens) extracts such as stems (AuSNPs-G.S), leaves (AuSNPs-G.L) and the mixture of both (AuSNPs-G.M), in which plant biomaterials were used as reducing and capping agents using a high energy ultrasound. The resulting AuSNPs were characterized using a wide range of instrumental techniques including UV–Vis spectrophotometry, FTIR, STEM, TEM, SEM, and EDS. The formation of AuSNPs was confirmed by UV–Vis, showing an absorption peak in the range of 532–540 nm. The FTIR analysis identifies the interactions between gold and the bioactive molecules implicated in nanoparticle synthesis. The STEM, TEM and SEM results determine the morphology of the AuSNPs responsible for the three different extracts in the synthesis process. Biosynthesized AuSNPs have an average size of 16–33 nm with varied morphology. Then, for the first time we have demonstrated an eco-friendly sensor based on Sonogel-Carbon electrode (SNGCE) modified with biosynthesized AuSNPs-G.M for phenol determination. This sensor was showing a lower limit of detection of 67 nM (n = 3), excellent sensitivity, reproducibility, repeatability and high selectivity; thanks to the AuSNPs as cost-effective nanomaterials. Finally, the analytical sensor was applied successfully for the determination of phenol in real sample olive oil with a satsisfactory recoveries.