Development of an electrochemical sensor based on ternary oxide SiO 2 /Al 2 O 3 /SnO 2 modified with carbon black for direct determination of clothianidin in environmental and food samples.

This study presents the development of an electrochemical sensor, denoted as GCE/CB/SiAlSn, based on the modification of a glassy carbon electrode surface with the ternary oxide SiO 2 /Al 2 O 3 /SnO 2 associated with carbon black, for direct determination of the neonicotinoid pesticide clothianidin in different matrices, such as environmental and food samples. Morphological characterization by the scanning electron microscopy technique, electroanalytical analyses using the cyclic voltammetry technique and differential pulse voltammetry are presented which demonstrated that the developed electrochemical platform presents high sensitivity in the electroanalytical clothianidin determination. The linear range studied was from 2.99 × 10 -7 to 6.04 × 10 -5 mol L -1 , with an LOD of 2.47 nmol L -1 . This high sensitivity was explained using the synergistic relationship between carbon black and ternary oxide that maximized the electroactive surface area of the GCE/CB/SiAlSn sensor. Interferent studies were performed that showed high selectivity of the sensor to the pesticide in the presence of Ca 2+ , K + , Na + , and Mg 2+ and carbendazim, glyphosate, imidacloprid and thiamethoxam pesticides. The sensor was applied to real samples of tap water and apple juice obtaining recoveries from 91.0% to 103.0%.