Determinação eletroanalítica de eugenol em óleo de cravo usando a Voltametria de Micropartículas Imobilizadas.

Eugenol (4-allyl-2-methoxyphenol) is the major phenolic component of clove oil and it can be extracted from cloves, cinnamon and other aromatic compounds [1]. It has been used in the pharmaceutical, agricultural, cosmetic and food industries [2]. In electroanalytical chemistry, the determination of eugenol employing Voltammetry of Immobilized Microparticles (VIM) is reported for the first time in this work. The construction of the electrode was based on glassy carbon substrate modified with dihexadecyl hydrogenphosphate(DHP)film containing carbon black nanoparticles and eugenol standard or clove oil sample immobilized. Electrochemical experiments were performed using a Potentiostat/Galvanostat Autolab PGSTAT204 (Metrohm-Autolab, Utrecht, Netherlands) controlled by NOVA 2.0 software (Eco Chemie) fitted with an electrochemical cell containing three electrodes (15 mL): Ag/AgCl (3.0 mol L−1 KCl) reference electrode, Pt foilas the counter electrode and GCE modified with a DHP film containing immobilized carbon blackparticles and the eugenol standard or sample as the working electrode. The operating condition sand the parameters influence(involving several chemical and instrumental parameters) were optimized by Square-Wave Voltammetry(SWV). Therefore, the effects of supporting electrolyte (Britton-Robinson buffer and phosphate buffer solution), pH (2-9), ionic strength (0.1, 0.2 and 0.4 mol L-1) and parameters of SWV, amplitude (10-170mV), frequency (10-45 Hz) and step (1-9 mV) were optimized. SWV measurements were performed in 0.2 mol L−1 phosphate buffer solution (pH = 2.0). The experimental conditions were: Estart: 0.25V, Eend: 0.9V, amplitude: 90 mV, frequency: 30 Hz and step: 5mV. The analytical curve for eugenol was constructed in the linear range of 2.9 x 10-8to 2.6 x 10-5g (correlation coefficient of 0.999) with LOD and LOQ of 8.7 and 29ng, respectively.Three commercial clove oil samples were successfully immobilized and analysed using the proposed VIM procedure for eugenol determination, showed concentrations ranging from 14 to 68.3%. Comparing the results obtained by the proposed and comparative procedures (spectrophotometric), RSD values between 0.08 to 3.54% were calculated, demonstrating the concordance of the results obtained by both methods.Therefore, the results reported in this work represent an exciting novelty in the scenario of electroanalytical chemistry and different new applications can be performed.