The Novel Carbon Nanomaterials Electrochemical Sensor for Determination of Trace Aluminum in Human Body Fluids With 8-Hydroxyquinoline

The novel carbon materials modified electrodes are prepared by multi-walled carbon nanotubes (MWNTs) and chemical reduced graphene (CRG) nanosheets. The modified electrodes can detect aluminum(III) in biological samples using 8-hydroxyquinoline (8-HQ) as a sequestering agent. The modified electrodes are characterized by cyclic voltammetry, transmission electron microscopy, and infrared spectrum. The electrochemical behaviors of 8-HQ with and without aluminum at the modified electrodes are investigated by linear scan voltammetry (LSV). The experimental results show the electrochemical activities of the new carbon material modified electrode that are improved greatly and compared with the bare glassy carbon electrode. This novel method is based on the property that LSV anodic peak current of 8-HQ decreases linearly when the concentration of aluminum increases. Under the optimum experimental conditions (pH7.5, 0.1 mol/L Tris-HCl buffer solution, and 2×10^-4 mol/L 8-HQ), the linear range and detection limit are 7×10^-7 mol/L-8×10^-6 mol/L, 3.1×10^-7 mol/L for CRG and 7×10^-7 mol/L-8×10^-6 mol/L, 1.7×10^-7 mol/L for MWNT, with 5×10^-6 mol/L Al(III). Eight measurements are carried out for each modified electrode, and the relative standard deviation of the results is found to be 2.4% (MWNT) and 3.2% (CRG), respectively. The modified electrode exhibits good stability and is used to detect aluminum concentration in biological fluids, including human serum and cerebrospinal fluid. The recoveries are 87.5%-90.0% for CRG and 92.5%-95.0% for MWNT, respectively.