Molar absorptivities of 2,4-D, cymoxanil, fenpropidin, isoproturon and pyrimethanil in aqueous solution in the near-UV.

摘要: Abstract The absorption spectra of five pesticides, namely 2,4-dichloro-phenoxy acetic acid (2,4-D), cymoxanil, fenpropidin, isoproturon and pyrimethanil, have been measured in aqueous solution using a set-up consisting two parallel cells coupled to CCD detector. absolute values their molar absorptivity coefficients ɛ were determined the wavelength-range 240–344 nm with deuterium-lamp at room temperature (298 ± 2 K). Using Beer–Lambert law, also 253.7 nm Hg-Lamp:  = 145 ± 14 for 2,4-D,  = 7940 ± 920  = 196 ± 14  = 7330 ± 880 isoproturon,  = 13200 ± 1400 pyrimethanil (in units M −1  cm ). quoted errors correspond 2 σ obtained from least square fit analysis estimated systematic error 5% due uncertainties concentrations. For all studied compounds, absorbances lower than 2.3 did not exhibit any deviation Beer–Lambert's law. Our experimental data are discussed compared UV similar molecules when such available literature. Based on calculated fractions these pesticides phase, direct photolysis under sunlight environment could occur, except may be either water surfaces or droplets contained atmospheric clouds.