Electrochemical determination of 10-hydroxycamptothecin using a multi-wall carbon nanotube-modified electrode

We report a sensitive and convenient voltammetric method for the direct determination of 10-hydroxycamptothecin (HCPT). At a multi-wall carbon nanotube (MWNT)-modified electrode, HCPT yields a very sensitive and well-shaped oxidation peak, which can be used as analytical signal for HCPT determination. Compared with the poor electrochemical signal at the unmodified GCE, the electrochemical response of HCPT at the MWNT-modified GCE was greatly improved, as confirmed by the significant peak current enhancement. This result indicates that the MWNT-modified GCE has great potential in the sensitive determination of HCPT. Based on this, a very sensitive and simple electrochemical method was proposed for HCPT determination after all the experimental parameters were optimized. The newly-proposed method possesses very low detection limit (2 x 10(-9) mol L-1) and wider linear range (from 1 x 10(-8) to 4 x 10(-6) mol L-1). Rapid and simple sample analysis is another advantage. Finally, this method was successfully demonstrated using HCPT drugs.