Nanomolar Level Determination of Octyl Gallate in Fats and Oils

Monitoring of synthetic phenolic antioxidants in food is very important due to their potential harmfulness to human beings. Octyl gallate (OG) is a commonly used phenolic antioxidant as a preservative in food stuff such as margarine, lard, sunflower oil etc. Herein, a glassy carbon electrode (GCE) chemically modified with gold nanoparticles (AuNPs) followed by self-assembled monolayer of dodecane thiol (DDT) was fabricated and employed for the determination of OG. An anodic peak corresponds to the oxidation of OG was observed at a potential of 0.22 V at DDT/AuNPs/GCE by square wave voltammetry. Based on this, a novel electrochemical sensor was developed for the determination of OG in oils and fats. Linear calibration graph was obtained within the range 1.2 to 0.2 mu M. The detection limit was found to be 8.3 nM which is remarkably lower than those reported previously. The applicability of the method was demonstrated by analyzing OG in commercially available food samples such as margarine, butter and sunflower oil.