Electrochemical sensor based on molecularly imprinted poly(ortho-phenylenediamine) for determination of hexahydrofarnesol in aviation biokerosene

Abstract

In this work, the first electrochemical sensor for determination of hexahydrofarnesol in aviation biokerosene was developed by electropolymerization of a molecularly imprinted ortho-phenylenediamine film on a glassy carbon electrode. The modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, RAMAN spectroscopy and atomic force microscopy. Parameters that influence the performance of the imprinted sensor, such as the molar ratio between functional monomer and template molecule, number of cycles and pH used in the electropolymerization, extraction time of the template molecule, and time of rebinding of the hexahydrofarnesol molecules in the imprinted cavities were optimized. The developed sensor presented the following linear ranges: 4.0 × 10−8 to 1.5 × 10-7 mol L-1 and 1.5 × 10-7 to 1.5 × 10-6 mol L-1. The apparent dissociation constant (KD) for the first linear range of this device calculated by the isothermal Langmuir adsorption model was 4.8 × 10-7 mol L-1. The limit of detection, limit of quantification and sensitivity were 1.2 × 10−8 mol L-1, 4.1 × 10−8 mol L-1 and 67 A L mol-1 (n = 3) respectively. The sensor showed considerable inter-day and intra-day repeatability, with RSD values ≤ 4.8%, and had 96% of its initial current preserved after being stored for 10 days in contact with air at room temperature. The developed method was successfully applied toward the determination of hexahydrofarnesol in aviation biokerosene. Mean recoveries ranged from 97.6% to 105.8%, with RSDs within the interval of 1.7% to 3.9%. These results indicate that the method developed has a good accuracy for the determination of hexahydrofarnesol.