Fabrication of carbon nanotube-polylactic acid composite electrode by melt compounding for capillary electrophoretic determination of tectoridin and irigenin in Belamcandae Rhizoma

A carbon nanotube-polylactic acid composite electrode was facilely fabricated by melt compounding for enhanced amperometric detection and capillary electrophoretic measurement of tectoridin and irigenin in Belamcandae Rhizoma. [Display omitted] •Carbon nanotube-polylactic acid composite was prepared by melt compounding.•The composite was packed in capillary under heat to fabricate detection electrode.•Belamcandae Rhizoma was examined by the electrode and capillary electrophoresis.•Tectoridin and irigenin in the herbal were determined with satisfactory results.•The sensitivity and stability of the electrode were enhanced by carbon nanotubes. A sensitive detection electrode based on the composite of carbon nanotubes (CNTs) and polylactic acid (PLA) was fabricated for measuring the bioactive constituents in Belamcandae Rhizoma by capillary electrophoresis (CE). The composite was facilely fabricated by packing a blend of CNTs and melted PLA into a fused silica capillary under heat. The prepared CNT-PLA composite was characterized by scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry. The results indicated that PLA bound electrically conductive CNTs to form a well-dispersed composite network for electrochemical sensing. The electrode was employed to the off-line detection of tectoridin and irigenin in Belamcandae Rhizoma to demonstrate its performance in capillary electrophoresis. At a separation voltage of 12 kV, the two isoflavones were well separated and detected within 8 min in a 40-cm fused silica capillary in a borate buffer at pH 9.8. The detection limits for tectoridin and irigenin were measured to be 0.24 and 0.21 μM, respectively.