Glycerol determination by chronoamperometry using Ni(OH)2/RGO on carbon paste electrode

Abstract

Glycerol is a by-product obtained in the transesterification reaction together with biodiesel, a necessary renewable fuel. The presence of glycerol in fuel can bring up environmental harm and engine damage, making fuel quality control important. In this context, composite electrodes (CE) were developed with low-cost materials like syringes, copper wire, graphite, and paraffin. The surface of composite electrodes was modified with reduced graphene oxide (RGO) and hydroxide nickel (Ni(OH)2). SEM, EDX, Raman, and FT-IR ATR characterized the developed material. The electrooxidation of glycerol in an alkaline medium containing 0.10 M of NaOH was investigated by CV. In the presence of glycerol, the modified electrode increased the anodic and cathodic peak current with an anodic peak potential shift to 0.54 V. The electrodes were employed in a study of the determination of glycerol in real biodiesel samples by a chronoamperometric technique. The modified electrode showed a sensitivity of 1.63 × 103 µA mM and a LOD for glycerol of 2.24 × 10–5 M (R = 0.996). The mean response time of the modified electrodes to glycerol was 1.85 s. These electrodes show good reproducibility and competitive detection limit compared to the literature. The proposed method presented satisfactory results, with 94.98 and 100.39% sample recoveries. Graphical abstract: [Figure not available: see fulltext.]