Electrochemical determination of atropine at multi-wall carbon nanotube electrode based on the enhancement effect of sodium dodecyl benzene sulfonate

Herein, a new electrochemical method was described for the determination of atropine based on the enhancement effect of an anionic surfactant: sodium dodecyl benzene sulfonate (SDBS). In pH 10.5 tetramethyl ammonium hydroxide as supporting electrolyte and in the presence of 0.4 x 10(-4) M SOBS, atropine yields a well-defined and sensitive oxidation peak at the multi-wall carbon nanotube electrode (MWCNTE). Compared with that in the absence of SOBS, the oxidation peak current of atropine remarkably increases in the presence of SOBS. The experimental parameters, such as supporting electrolyte, concentration of SOBS, and accumulation time, were optimized for atropine determination. The oxidation peak current is proportional to the concentration of atropine over the range from 3.98 ng/ml to 27.23 ng/ml. The detection limit is 0.449 ng/ml after 2 min of accumulation. This new voltammetric method was successfully used to determine atropine in Indian traditional medicine (seeds and leaves of Datura stramonium) with satisfactory recoveries. The developed method was also used for the analysis of atropine in pharmaceutical formulation of ophthalmic solution (eye drop). The relative standard deviations of intraday and interday analyses for atropine were 0.67% and 0.86% respectively (n = 3) for the accumulation time of 120 s. (C) 2011 Elsevier B.V. All rights reserved.