Ultrasensitive voltammetric detection of an antimalarial drug (amodiaquine) at a disposable and low cost electrode

In this study, an ultrasensitive electrochemical determination of an antimalarial drug, amodiaquine (ADQ), was described at a cheap and disposable pencil graphite electrode (PGE) which offers a renewable sensing surface for each measurement. The electrochemical behavior of ADQ was investigated on various carboneous electrodes. Cyclic voltammograms showed that ADQ gives reversible peaks at all electrodes. However, the highest currents for oxidation of ADQ and reduction of the oxidized form of ADQ (ADQ((Ox))) among the carboneous electrodes were obtained in the case of using PGE and these redox couple become more reversible and sharper at PGE than the other electrodes. DP voltammograms also showed that the oxidation peak current of ADQ at PGE is about five times higher than at other electrodes. All these results indicate that bare PGE without any modification exhibits an excellent electrocatalytic activity towards oxidation of ADQ. DP voltammetric studies show a wide linear dynamic range from 1.0 to 200 nM with a detection limit and sensitivity of 0.30 nM and 50 mu A mu M-1, respectively. The recovery of ADQ spiked into some different samples was studied. Obtained recovery values (99.2-102.0%) confirmed that non-modified PGE can be used for the ultrasensitive and accurate electrochemical quantification of ADQ in different samples.