Study of nimesulide and its determination using multiwalled carbon nanotubes modified glassy carbon electrodes

A new method for the determination of nimesulide was established based on the multiwalled carbon nanotubes (MWCNTs) modified glassy carbon electrode (MWCNTs/GCE). In 0.2 M PBS (pH 6.6) buffer solution, the MWCNTs/GCE showed a remarkable catalytic and enhancement effect on reduction of the nimesulide. The reduction peak potential of nimesulide shifted positively from -0.665 V at bare GCE to -0.553 V at MWCNTs/GCE, and the sensitivity increased ca. 7 times. A linear dynamic range of 3.2 x 10(-7) -6.5 x 10(-5) M (R = 0.9992) with a detection limit of 1.6 x 10(-7) M was obtained. The electrochemical behaviors of nimesulide were studied and electron-transfer coefficient (alpha = 0.45), proton number(X = 1)and electron-transfer number (n = 2) have been determined. This method has been used to determine the content of nimesulide in medical tablets. The recovery was determined to be 93.2-106.2% by means of standard addition method. Compared with UV-vis spectrometry, the method was not remarkable difference. (C) 2009 Elsevier Ltd. All rights reserved.