The electrochemical behavior of methylparathion under UV irradiation was mo
nitored by polarography in an aqueous medium (pH 6.5) at 254 and 366 nm, an
d the effects of atmospheric oxygen and TiO2 On methylparathion were also l
ooked at. Dissapearance of the methylparathion and appearance of two major
electroactive degradation products were observed. The reaction rate constan
ts for the process ranged from 3.55 x 10(-5) to 5.69 x 10(-5) s(-1), and th
e reaction showed pseudo-first-order kinetics. The methylparathion transfor
mation did not depend on the experimental conditions. Spectroscopic and ele
ctrochemical data suggest the presence of p-nitrobenzoic acid as a common e
lectroactive product.