A versatile sensing platform based on FeOOH nanorod/expanded graphite for electrochemical quantification of bioanalytes

Quantitative analysis of biologically important compounds plays extraordinary roles in diagnostic studies of human health. In this study, a versatile electrochemical sensing platform is proposed for selective quantification of ascorbic acid (AA), dopamine (DA), uric acid (UA), acetaminophen (AC) and l -tryptophan (Trp). Such a platform is based on a nanocomposite of FeOOH nanorod and expanded graphite (FeOOH nanorod/EG), prepared through a hydrothermal process. The characterization of its morphology and electrochemical properties by means of microscopic methods and electrochemical techniques reveals that this nanocomposite exhibits outstanding electrocatalytic activity and sensing performance toward these bioanalytes. A combined action between EG and FeOOH is confirmed, where the former provides a huge electroactive surface area as well as a fast electron transfer rate, while the latter features strong electrical catalytic ability. This platform exhibits high sensitivity toward voltammetric quantitation of AA, DA, UA, AC and Trp, and their detection limits are 3.28, 0.22, 0.02, 0.0014 and 0.03 μM (S/N = 3), respectively. Beyond that, the proposed FeOOH nanorod/EG electrochemical sensing platform shows good selectivity, high reproducibility and stability in the quantitative analysis of these bioanalytes. The established sensing platform has been also successfully adopted in analyzing these bioanalytes in real biological serum and urine samples or commercial drugs. Consequently, the fabricated FeOOH nanorod/EG nanocomposite is a promising electrode material in the applications of sensing different bioanalytes.