DETERMINATION OF DINOSEB BY ADSORPTIVE STRIPPING VOLTAMMETRY USING A MERCURY FILM ELECTRODE

An adsorptive stripping voltammetric method for the determination of t he pesticide dinoseb (2-sec.-butyl-4,6-dinitrophenol) at the mercury f ilm electrode is described. The deposition of the mercury film on a gl assy carbon disk electrode was optimized. The temperature, at which th e mercury film was deposited, was demonstrated to have a strong influe nce on the stripping peaks, the first one being much more intense than the second. A systematic study of the variables affecting the strippi ng response was carried out by differential pulse voltammetry. The res ults obtained have been compared with those at the HMDE; a significant improvement in the sensitivity of the method developed with the MFE w as observed. Using a 300 s accumulation time, the limits of determinat ion and detection were 3.6 x 10(-10) and 1.1 x 10(-10) mol L-1, respec tively. The effect of the presence of several herbicides on the dinose b response was also tested. The method has been applied to the determi nation of the pesticide in spiked apple juice at two concentration lev els: 12.0 and 1.2 mug L-1 of juice.