Surface enhancement of porous alumina microfibers toward electrochemical sensing of chlorogenic acid

Abstract Porous alumina microfibers with a diameter of 125 nm were prepared through hydrothermal reaction in urea solution using aluminium nitrate as the precursor, and characterized using transmission electron microscopy and scanning electron microscopy. The mechanism of oxidation of chlorogenic acid was examined using cyclic voltammetry, indicating a reversible two-electron process. Compared with the bare carbon paste electrode (CPE), the oxidation signals of chlorogenic acid were greatly enhanced with the alumina microfiber-modified CPE. Chronocoulometry experiments indicated that the accumulation of chlorogenic acid on the surface of the alumina microfibers was obviously improved relative to that on the bare electrode, which is attributed to the numerous micropores and regular fiber-like structures. Based on the signal amplification ability of the porous alumina microfibers, a novel electrochemical sensing platform was developed for chlorogenic acid. The linear range was 10–2000 μg L −1 , and the limit of detection was evaluated to be 5.0 μg L −1 . The practical application of this new method was demonstrated using honeysuckle and soft drink samples. The results were consistent with the values obtained by high-performance liquid chromatography.