Adsorptive stripping voltammetric determination of podophyllotoxin, an antitumour herbal drug, at multi-walled carbon nanotube paste electrode

Abstract

Adsorption stripping voltammetry, a very sensitive electroanalytical method, was employed to determine podophyllotoxin, a kind of antitumour herbal drug at a multiwall carbon nanotube (MWCNT)-modified carbon paste electrode (CPE) surface. In the following anodic sweep from 0.5 to 1.5 V, podophyllotoxin, adsorbed at the MWCNTmodified CPE surface, was oxidized and yielded a sensitive oxidation peak with E 1/2 /E p approximately 1.16 V/1.18 V over the scan rates of 10-120 mV s -1 . From CV and SWV studies of podophyllotoxin in the acetate buffers of various pH values, it was found that protons were involved in the oxidation of the drug at the H ? /e -ratio of one (DE p / pH = 56 mV at 25°C). Its electrochemical behaviour was irreversible. The experimental conditions, such as supporting electrolyte, pH value, accumulation time, ionic strength and scan rate, were optimized for the measurement of podophyllotoxin. The best results were obtained in 0.02 M acetate/acetic acid buffer (pH 4.6) containing 0.04 M KCl (1:49, v/v) for 60 s accumulation. The oxidation peak current varies linearly with the concentration of podophyllotoxin over the range of 199-1796 pg mL -1 . The limits of detection and quantification of the pure drug are 4.5 and 14.96 pg mL -1 , with the correlation coefficient, r = 0.998 and the relative standard deviation, RSD = 1.3% (n = 5). This new method was successfully applied to the determination of podophyllotoxin in a plant sample of the rhizome of Podophyllum hexandrum. Recoveries were 99.173-101.231%. The relative standard deviations of intraday and interday analyses for podophyllotoxin were 0.55 and 0.61%, respectively (n = 3).

WITHDRAWN: Electrochemical behavior of kaempferol and its determination in presence of quercetin employing multi-walled carbon nanotube modified carbon paste electrode

“…Hence, CMEs have been successfully utilized for M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 determination of various drug molecules in our laboratory [10][11][12][13]. Carbon nanotubes (CNTs) have become the subject of intense researches in the last decades because of their unique properties and the promising applications in any aspect of nanotechnology.…”

MWCNT-Chitosan-ZrO2 Nanocomposite Modified Sensor for Sensitive and Selective Electrochemical Determination of Serotonin

“…A sequential shift of the anodic peak potential with the augmentation of solution pH was also observed (Fig. 5), indicating that the protons participate in the electrode reaction process of 5-HT [30,31]. A linear dependence of peak potential on pH of the supporting electrolyte was obtained following a linear equation: E/mV = 787.4 -62.64 pH; R 2 = 0.997.…”

Electrocatalytic oxidative determination of reserpine at electrochemically functionalized single walled carbon nanotube with polyaniline

“…A linear For finding the adsorptive character of the drug at the electrode surface, a cyclic voltammogram was recorded after 60 s pre-concentration time at −0.15 V and second cycle at the same electrode. A substantial decrease in the peak current value in subsequent scans was observed, which reached a steady state, indicating that reserpine shows also adsorptive characteristics at electrode surface [30,31]. This finding is confirmed by plotting log i p against log (Fig.…”