Determination of Sulfamethoxazole with Multi-Walled Carbon Nanotubes-Sodium Dodecyl Benzene Sulfonate Modified Carbon Paste Electrode as Working Electrode

The self-made carbon paste electrode (CPE) was applied with a layer of multi-walled carbon nanotubes (MWCT) by dropping 2 μL of 1 g·L^-1 MWCT suspension onto its surface. After volatilization of the solvent, 2 μL of 1 g·L^-1 SDBS solution were applied to the surface by dropping and thus the modified electrode of MWCT-SDBS-CPE was prepared. It was found that through modification with MWCT and SDBS, change transfer of the electrode was decreased, resulting acceleration of electron transmission. As shown by the results of DPV in an acetate buffer solution of pH 5.0 (containing 0.005 mol·L^-1 NaNO₃ as supporting electrolyte), good electrochemical response of sulfamethoxazole (SMZ) was obtained at MWCT-SDBS-CPE. Linearity ranges of SMZ were found in the ranges of 2.0×10^-9 to 1.0×10^-7mol·L^-1 and 1.0×10^-7 to 1.0×10^-5mol·L^-1, with detection limit of 1.0×10^-9mol·L^-1. Precision was tested at 6.0×10^-6mol·L^-1 of SMZ for 5 determinations, value of RSD found was 4.9%.