Antioxidants detection in aviation biokerosene by high-performance liquid chromatography using gold nanoparticles anchored in reduced graphene oxide

This paper report the development of a new HPLC-pulsed amperometric detector (HPLC-PAD) for the determination of antioxidants using glass carbon electrode (GCE) modified with reduced graphene oxide (rGO) and gold nanoparticles (AuNPs). The modified electrode exhibited efficient electro-oxidation when it was applied in the analysis of three important antioxidants: N, N'-di-sec-butyl paraphenylenediamine (BPA), 2,6-Di-tert-butyl-phenol (TBP) and 2,6-Di-tert-butyl-4-methylphenol (BHT). The chromatographic separation was performed with an isocratic elution composed of acetonitrile/water (90:10% v/v) and 1% acetic acid. The chromatograms showed good separation of all components in periods of time less than 10 min. The developed method presented linear ranges of 5.0 x 10(-6) -1.3 x 10(-4) mol L-1 (BPA), 2.5 x 10(-6) -1.0 x 10(-4) mol L-1 (TBP) and 7.5 x 10(-7) -1.3 x 10(-4) mol L-1 (BHT), and the analytical curves presented limits of detection of 1.2 x 10(-7), 1.7 x 10(-7) and 7.8 x 10(-8) mol L-1 for BPA, TBP and BHT, respectively. The values obtained for the recovery studies conducted ranged from 97.3 +/- 1.5% to 101.5 +/- 2.1%. The results showed that the method is reliable, since it presented high sensitivity, precision and accuracy. The developed method was successfully applied for the determination of antioxidants in a sample of biokerosene, consisting of isoparaffins synthesized from fermented and hydroprocessed sugars. The determined concentrations were TBP 3.1 x 10(-5) +/- 5.5 x 10(-6) mol L-1 and BHT 3.3 x 10(-5) +/- 2.9 x 10(-6) mol L-1.