Generation IV ionic liquids and nanomaterials to develop innovative electrochemical biosensing platforms

Different types of modified electrodes have been prepared and tested to assembly and construct portable sensing devices, useful to analyze, in a simple, fast and economic way, many analytes. Bare glassy carbon electrodes (GCE) of the screen-printed type (SPE), with silver electrode as reference, have been modified, via drop casting on the working electrode surface, with a mixture of generation IV room temperature ionic liquids (RTILs) and nanomaterials. The ionic liquids choline-amino acids, were synthetized in our laboratory following the methodology known in literature1. These RTILs differ from the previous generation ones because they are nontoxic and completely biodegradable2,3. Like those of the previous generations, the RTILs used in this work have interesting properties regarding low volatility, low flammability, high ionic conductivity, high chemical and electrochemical stability4. Furthermore, these compounds allow to significantly increase the work potential range (V), electroactive area (Aea) and electron transfer constant (k0), so that anode or cathode peaks can be detected even for extremely low concentration of analytes. The nanomaterials used in this work were Multi-Walled Carbon Nanotubes (MWCNT) and Titanium Dioxide nanoparticles (anatase form). These two nanomaterials have been used both alone and together in different proportions with the chosen RTIL [Ch] [Phe]. All the so developed electrodes have been studied by means of cyclic voltammetry measurements to calculate the electroactive area (Aea) of the working electrode, in order to find the best combination of nanomaterials/ionic liquid/water for the drop casting mixture. All the proposed combinations have also been studied for stability: cyclic voltammetry measurements have been carried out at various time intervals after the preparation to investigate variations of the Aea of the modified electrodes. The electrochemical platform so developed has been used, after functionalization with the proper enzyme, as a biosensor. In particular, it has been tested for measuring glucose in food matrices and antioxidants in olive oils using Glucose Oxidase5 and Lipase6 respectively. References 1. S. De Santis, G. Masci, F. Casciotta, et al.; Phys. Chem., 2015, 17,20687. 2. J. Arning, S. Stolte, A. Böschen, F. Stock, W.R. Pitner et al.; Green Chem., 2008, 10, 47-58. 3. A. Romero, A. Santos, J. Tojo, A. Rodriguez; J. Hazard Matter, 2008,151,268-273. 4. J.S. Xu, G.C. Zhao;Int. J. Electrochem. Sci., 2008, 4, 519-527. 5. M.L. Antonelli, F. Arduini et al.;Biosensors and Bioelectronics, 2009,24,1382-88. 6. Álvarez G.A., J.A. Rodríguez, J.C. Escamilla, C.A. Galán;J. Mex. Chem. Soc., 2015, 59, 19-23.