The Electroanalytical Detection of Triglyceride Concentrations in Olive Oil using Modified Screen Printed Electrodes with Ionic Liquid [1-(2-Ethoxyethyl)-1-Methylpyrrolidinium Bis(Trifluoromethylsulfonyl)Imide]-Lipase

Abstract

The electroanalytical detection of triglyceride concentrations in olive oil using modified screen printed electrodes with Ionic Liquid [1-(2-ethoxyethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide]-lipase was reported for the first time. In this study, 1-(2-ethoxy-ethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C2OC2C1pyrr][N(Tf)2] was used as an ionic liquid due to the high ionic conductivity and good biocompatibility to enhance the electrochemical response. The mixture of [C2OC2C1pyrr][N(Tf)2]-GA-Lipase was immobilized on the surface of the screen printed carbon electrodes (SPCE) by drop casting technique. The electrochemical performance and mechanism of C/[C2OC2C1pyrr][N(Tf)2]-GA-Lipase modified electrode was investigated using cyclic voltammetry (CV). The surface morphology of the modified SPCE was also studied using SEM. The optimization parameters of C/[C2OC2C1pyrr][N(Tf)2]-GA-Lipase electrodes were carried out, and shows that pH 7, 30°C and 5 % of lipase enzyme loading resulted in optimum performance. The electroanalytical methodology proposed in this manuscript was successfully applied in the determination of triglyceride concentrations in olive oil. The limit of detection (LOD) and response time were 0.68 mM and 46 seconds respectively. A linear calibration range from 0.67 to 2.68 mM was also obtained. Common interfering compounds on the sensor were investigated using cyclic voltammetry. Furthermore, the biosensor was effectively validated using gas chromatography analysis.