Three Different Spectrophotometric Methods for Simultaneous Determination of Pyriproxyfen and Chlorothalonil Residues in Cucumber and Cabbage Samples

Figure 9

Ratio spectra (a) and first derivative ratio spectra (b) of pyriproxyfen (1, 2, 3, 5, 7, 10, 15, 20, 25, and 30 μg·mL⁻¹) when 1.5 μg·mL⁻¹ of chlorothalonil was used as the divisor in methanol (∆λ = 4 nm).

(a)

(b)