A novel N-doped carbon nanotube fiber for selective and reliable electrochemical determination of ascorbic acid in rat brain microdialysates

Selective and reliable method is of great importance for in vivo analysis in the complicated brain. In this work, we developed a new approach for detection of ascorbic acid (AA) based on a new nitrogen-doped nanotube fiber (NCNF) microelectrode. After electrochemical pre-treatment, the NCNF microelectrode (e-NCNF) demonstrated high electrocatalytic capability for AA oxidation with a low working potential, 0 V, resulting in high selectivity for detection of AA level against other biological species in brain, as well as producing high sensitivity. Moreover, the e-NCNF was directly assembled by carbon nanotube bundles, free from the post-modification, thus showing high reproducibility, in which the deviation of anodic current intensity of six electrodes prepared with same method did not exceed 4% (RSD, n = 6). Based on the remarkable analytical performance, the e-NCNF with good biocompatibility was successfully applied to determine the AA level as 134 ± 7 mM, in rat brain microdialysates.