"The biosensors based on carbon paste electrode modified with the crude tissues of banana, apple, mushroom, potato, pear plant as polyphenol oxidase source for quantification of phenolic compounds were studied. The ratio between components (carbon - tissue - paraffin), was investigated to optimize the electrode material with better electro analytical performance usingSCV (Stare Case Voltametry)techniques in 0.1 M sodium phosphate buffer, pH 7, scan rate 50 mV/s. The best results of CPEB sensor regarding the background current, sensitivity and correlation coefficients were obtained when the mixture of 1g graphite powder/ 300 μl paraffin and 0.1 gr tissue was used. The electrochemical behavior of carbon paste electrode modified with different kind of crude tissues is compared with electrochemical behavior of unmodified electrode.  Relative response of biosensor modified with crude tissue of banana (CPEB) and apple (CPEA) to different phenolic compounds is studied. The CPEB biosensor shows high sensitivity to hydroquinone (S=3.25mA/ppm) and lowest detection limit (1.02 ppm) to phenol. CPEA biosensor shows better sensitivity for 4-clorphenol (S=1.35mA/ppm) and lowest detection limit (0.13ppm) to phenol substrate." [...]

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