Electroanalytical determination of eugenol in clove oil by voltammetry of immobilized microdroplets.

The determination of eugenol employing voltammetry of immobilized microdroplets (VIM) is reported in this work. The construction of the electrode was based on a glassy carbon substrate modified with carbon black nanoparticles and eugenol standard or clove oil sample within a dihexadecyl hydrogen phosphate (DHP) film. The different experimental parameters related to this proposed procedure, i.e., supporting electrolyte composition, pH, ionic strength, and square-wave voltammetry (SWV) parameters (amplitude, frequency, and step potential) were optimized. By doing that, the SWV measurements were performed on the following optimum experimental conditions: 0.2 mol L−1 phosphate buffer solution (pH 2.0), amplitude 90 mV, frequency 30 Hz, and step potential 5 mV. The analytical curve for eugenol was linear in the wide range from 0.03 to 26 μg (r = 0.999) with limits of detection (LOD) and quantification (LOQ) of 0.13 and 0.42 ng, respectively. Three commercial clove oil samples were successfully immobilized and analyzed using the proposed VIM procedure showing eugenol concentrations ranging from 14.0 to 68.3%. Comparing the results obtained by the proposed and comparative procedure (spectrophotometric), relative standard deviations (RSDs) lower than 5.0% were verified, demonstrating the concordance of the results obtained by both methods. [ABSTRACT FROM AUTHOR]